ALBERT

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 188〈/p〉 〈p〉Author(s): Naser Abdi, Yaser Abdi, Zahra Alemipour〈/p〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 188〈/p〉 〈p〉Author(s): Smajil Halilovic, Jamie M. Bright, Wiebke Herzberg, Sven Killinger〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Knowledge of horizontal solar irradiance is crucial for the nowcasting and forecasting of generated photovoltaic (PV) power. High quality irradiance measurement devices, however, are typically not collocated with PV systems. The lack of measurements can be compensated by numerical weather models or satellite-derived products, but they provide only limited temporal and spatial resolutions. Another possibility is to directly use PV systems as irradiance sensors, since the measured PV power is a good indicator of incoming solar irradiance. The challenging part in this procedure is the computation of the global horizontal irradiance 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si233.svg"〉〈mrow〉〈msub〉〈mrow〉〈mi〉G〈/mi〉〈/mrow〉〈mrow〉〈mi〉h〈/mi〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉 from the global tilted irradiance 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si234.svg"〉〈mrow〉〈msub〉〈mrow〉〈mi〉G〈/mi〉〈/mrow〉〈mrow〉〈mi〉c〈/mi〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉, because a combination of decomposition and transposition models is not analytically invertible. Hence, the majority of existing solutions to this problem are numerical procedures. In this paper, an analytical approach to compute 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si235.svg"〉〈mrow〉〈msub〉〈mrow〉〈mi〉G〈/mi〉〈/mrow〉〈mrow〉〈mi〉h〈/mi〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉 from 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si236.svg"〉〈mrow〉〈msub〉〈mrow〉〈mi〉G〈/mi〉〈/mrow〉〈mrow〉〈mi〉c〈/mi〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉 is presented. The comparison of the proposed approach with one of the existing iterative (numerical) approaches shows promising results. When applied to 1-min data at four different locations, the new approach outperforms the iterative procedure by up to 9% in terms of the relative root mean square error (rRMSE) for east/west module’s orientations, and performs slightly better with the south orientation. Moreover, the new approach provides results in less than 1 s, whereas the iterative procedure requires more than 20 min for a one year of data. An open source R-script of the new approach is also publicly available and provided as supplementary material.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 188〈/p〉 〈p〉Author(s): Dazhi Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Previously in “SolarData: An R package for easy access of publicly available solar datasets” [Sol. Energy 171 (2017) A3–A12], the R package 〈code〉SolarData〈/code〉 was built for easy access of five publicly available solar datasets. In this update, code for reading data from the Baseline Surface Radiation Network (BSRN), the largest research-grade solar radiation monitoring network, is added to the package. BSRN comprises 66 stations (as of 2019-02) around the globe, which collect 1-min or 3-min radiation data since 1992. These data are stored in the so-called “station-to-archive” files, each containing records from one month and one station, and can be downloaded via ftp. The functions in 〈code〉SolarData v1.1〈/code〉 directly interact with these station-to-archive files, without using the BSRN-Toolbox. It should however be noted that 〈code〉SolarData〈/code〉 is not a replacement of BSRN-Toolbox. Instead, it gives R users improved accessibility and freedom in BSRN data manipulation. Like the previous release, all contents herein described are made available on GitHub.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 188〈/p〉 〈p〉Author(s): B. Sri Revathi, Prabhakar Mahalingam, Francisco Gonzalez-Longatt〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, a novel non-isolated DC-DC converter topology is proposed for solar photovoltaic (PV) application. The proposed converter is constructed from an interleaved boost converter (IBC) to reduce the input current ripple. Voltage gain is extended by (i) using voltage lift technique, (ii) replacing the conventional inductors of the IBC by coupled inductors (CIs) with appropriate turns ratio and (iii) connecting a voltage multiplier cell (VMC) across the secondary windings of the CIs. As the voltage gain is extended mainly at the secondary side of the CIs, the switches are subjected to low voltage stress which is only 12.63% of the output voltage. The converter yields a high voltage conversion ratio of 15.83. Experimental results obtained from a 24 V/380 V, 225 W prototype converter operating at 91.6% efficiency serves as a proof of the presented concept which has been employed to achieve high voltage conversion ratio (15.83) with low input current ripple (20%).〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 188〈/p〉 〈p〉Author(s): Sebastian Müller, Federico Giovannetti, Rolf Reineke-Koch, Oliver Kastner, Bernd Hafner〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We present a comparative simulative study to evaluate the efficiency and stagnation behavior of commercially available absorber coatings for solar thermal flat-plate collectors. A market survey has revealed different absorber coatings, which exhibit solar absorptances of α 〉 90% and thermal emittances ε of 5–90%. All these coatings can be classified as wet-chemically electroplated coatings on the basis of black chrome, highly selective sputtered PVD coatings, solar paints and novel thermochromic coatings. We calculated the annual solar collector energy output by means of collector simulations with the tool ScenoCalc and compared the collector efficiency of several absorber coatings. We have carried out TRNSYS simulations both with systems for solar domestic hot water preparation and solar-assisted space heating. In a solar domestic hot water system with a daily tapping volume of 100 L we report an increase in the auxiliary energy demand of up to 6% with black chrome, 7% with thermochromic and 21% with solar paint coatings compared to sputtered PVD coatings. In a solar combisystem the increase in the auxiliary energy demand does not exceed 1.4% for thermochromic and black chrome coatings and 6.1% for solar paints. The stagnation period can be reduced from 178 h per year (PVD coatings) to 118 h, 62 h and 11 h for black chrome, thermochromic and solar paint coatings, respectively. The maximum absorber temperatures decrease from 175 °C (PVD coatings) to 165 °C for black chrome, 145 °C for thermochromic and 135 °C for solar paint coatings.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0038092X19306383-ga1.jpg" width="493" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 188〈/p〉 〈p〉Author(s): S. Marikkani, J. Vinoth Kumar, V. Muthuraj〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In past days, the occurrence of toxic heavy metal ions into the water and soil environment causes a major health risk to the living organisms. In this work, we mainly focused on the photoreduction of hexavalent chromium (Cr〈sup〉6+〈/sup〉) using novel sponge-like Fe〈sub〉2〈/sub〉V〈sub〉4〈/sub〉O〈sub〉13〈/sub〉 photocatalyst under visible light irradiation. The sponge-like Fe〈sub〉2〈/sub〉V〈sub〉4〈/sub〉O〈sub〉13〈/sub〉 was tailored through hydrothermal process using ferric chloride and sodium metavanadate precursors without the addition of any templates. The surface morphology, elemental analysis and various physical properties are characterized by numerous spectroscopic techniques. Interestingly, the sponge-like Fe〈sub〉2〈/sub〉V〈sub〉4〈/sub〉O〈sub〉13〈/sub〉 demonstrated proficient photocatalytic performances towards the reduction of Cr〈sup〉6+〈/sup〉 into Cr〈sup〉3+〈/sup〉. The obtained UV–visible spectroscopy results portrayed that sponge-like Fe〈sub〉2〈/sub〉V〈sub〉4〈/sub〉O〈sub〉13〈/sub〉 could reduce above of Cr〈sup〉6+〈/sup〉 solution within 40 min. The effect of operational reaction parameters such as catalyst dosage, initial Cr〈sup〉6+〈/sup〉 concentration and pH of the solution was optimized. Moreover, the sponge-like Fe〈sub〉2〈/sub〉V〈sub〉4〈/sub〉O〈sub〉13〈/sub〉 holds very good stability even after five consecutive cycles. This study could open new insights for the design novel nanostructured binary metal oxides for environmental applications.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 188〈/p〉 〈p〉Author(s): Muhammad Qamaruddin, Ibrahim Khan, Oluwole Olagoke Ajumobi, Saheed Adewale Ganiyu, Ahsanulhaq Qurashi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work the synthesis of sulfur-doped cerium-titania based nanocomposites is carried out for photoelectrochemical (PEC) water splitting applications. Pristine ceria (CeO〈sub〉2〈/sub〉), titania (TiO〈sub〉2〈/sub〉) and S-CeTiO〈sub〉4−x〈/sub〉 nanohybrid have been synthesized via facile hydrothermal technique. Additionally, sulfur doping is performed at 350 °C to achieve sulfidized-CeTiO〈sub〉4−x〈/sub〉 (S-CeTiO〈sub〉4−x〈/sub〉) nanohybrid with improved optoelectronic properties. The energy disperse x-ray spectrometer (EDS) spectra and elemental mapping of S-CeTiO〈sub〉4−x〈/sub〉 showed the presence of sulfur. The X-Ray Photoelectron Spectroscopy (XPS) and X-ray diffraction (XRD) analysis further confirm sulfur doping and composite formation. Additionally, the XRD patterns of S-CeTiO〈sub〉4−x〈/sub〉 suggest the anatase phase of TiO〈sub〉2〈/sub〉, which is slightly mitigated with sulfidation. The Brunauer–Emmett–Teller (BET) isotherms indicate the average pore size decreases from 20.82 nm to 18.35 nm after sulfidation, which confirms successful sulfur incorporation in the pores. The Kubelka-Munk plots acquired from UV/Vis-diffuse reflectance spectroscopy (DRS) displayed a substantial red shift in the bandgap with sulfidization from 3.00 eV to 2.50 eV. The photoelectrochemical (PEC) water splitting of S-CeTiO〈sub〉4−x〈/sub〉 photoanode in terms of photocurrent density suggesting more than 3-times increase as compared to pristine TiO〈sub〉2〈/sub〉 nanoparticles. These results affirm the photoelctrocatalytic nature of ceria-based nanostructures for PEC water splitting.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 188〈/p〉 〈p〉Author(s): Seung-Ho Yoo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The solar architecture is defined as a kind of building integrated photovoltaic (BIPV) which the Photovoltaic (PV) modules are deployed to passive solar concepts, to minimize the heating & cooling load, to upgrade the indoor environmental quality and to be adjustable for regional weather and to continuously succeed architectural culture and history. The most ideal form of a BIPV is a multi-functional and ecological convergence through a passive concept application of a photovoltaic module for a building. The solar architecture needs to consider the architectural culture and history of the region through an ecological convergence which is applicable to a passive concept if the environment, energy and comfort problems will be effectively mitigated. The evaluation standard is needed to fulfill these requirements of solar architecture. The renewable energy sources are getting very hot issues, due to the environmental pollution, global warming, and energy shortage, etc. It is reasonable to disseminate the representative energy systems which could be ecologically convergent with the regional architecture. Most renewable energy systems including PV could not be activate or not be environmentally friendly if the systems are planned simply without multi-functional and ecological convergence. This paper describes the ecological criteria to optimize solar architecture through an ecological convergence of a passive solar architecture and photovoltaic system.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 188〈/p〉 〈p〉Author(s): L. Salgado-Conrado, Areli Lopez-Montelongo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, we identify and describe the barriers that limit the installation of solar water heating (SWH) systems in Mexico and the manner in which the Mexican government has been working toward overcoming these challenges. Data regarding architectural, technical, economic, marketing, social, and political barriers were collected from official governmental publications, Mexican journals, and articles, and compared with results from similar research articles. Our results revealed that the governmental programmes have positively motivated the adoption of SWH systems. However, issues related to the structural conditions of buildings, low income, and access to water limit their use. Therefore, these issues should be included in the governmental strategies.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 188〈/p〉 〈p〉Author(s): Mahmood Mastani Joybari, Fariborz Haghighat, Saeid Seddegh, Yanping Yuan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, a method to track the melting front of phase change materials (PCMs) is developed under simultaneous charging and discharging (SCD) inside horizontal triplex tube heat exchangers. For SCD, the heat transfer mode of internal heating and external cooling is investigated. According to the heat transfer mechanism within the PCMs, two models of pure conduction (PC) and combined conduction and natural convection (CCNC) are developed and solved using ANSYS Fluent (version 17.2). Generally, during charging (i.e. melting), the buoyancy forces induce the liquid PCM to move upwards; therefore, the upper section of the storage is affected. However, this motion is limited during SCD due to the simultaneous cooling from the outer tube. Therefore, a front tracking method is developed assuming that natural convection only contributes melting to the upper section of the storage unit. On the other hand, it is assumed that the melting front for the lower section behaves similar to the PC model. In this study, three PCMs are used in three geometries to develop the correlations using two dimensionless numbers; i.e. liquid fraction of the PC model and the storage radius ratio. Another PCM is then used to verify the method. The correlations can provide results in the range of ±15% discrepancy.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 188〈/p〉 〈p〉Author(s): Mahmoud Samadpour, Hieng Kiat Jun, Parisa Parand, M.N. Najafi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Here we report a general study on the effect of various semiconductor sensitizers i.e. CdS, CdSe, CdS/CdSe, and PbS/CdS on the performance of quantum dot sensitized solar cells (QDSCs). The electron life time in the cells is investigated by applied bias voltage decay method. We clearly indicate that the electron life time could be considerably enhanced by CdS pre-deposition in CdS/CdSe QD sensitized cells.〈/p〉 〈p〉The charge transfer properties of cells are investigated by impedance spectroscopy and it is shown that a clear downward shift in TiO〈sub〉2〈/sub〉 conduction band take place through CdS QDs sensitizer pre-deposition. According to the results, type and the sequence of QDs deposition has a clear effect on the recombination resistance in cells. Here the efficiency of solar cells was improved to 3.63% by CdS pre-deposition which is more than 25% improvement in comparison to CdSe sensitized cells (2.84%). This general study indicates that tuning the sensitizer type can be systematically used in QDSCs to increase the electron life time and consequently the cells’ performance in a simple and cost effective way.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 188〈/p〉 〈p〉Author(s): Yu Xie, Manajit Sengupta, Chenxi Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Fast All-sky Radiation Model for Solar applications with Narrowband Irradiances on Tilted surfaces (FARMS-NIT) reported in Part I of this study is enhanced to include the requirements for cloudy-sky conditions. Surface radiances in 2002 narrow-wavelength bands from 0.28 to 4.0 μm are analytically computed by solving the radiative transfer equation for five independent photon paths accounting for clear-sky absorption, Rayleigh scattering, and cloud absorption and scattering. The Simple Model of the Atmospheric Radiative Transfer of Sunshine (SMARTS) is used to provide the optical thickness of the clear-sky atmosphere. Unlike Part I, which approximates the computation of aerosol scattering using the single-scattering phase function, the cloud transmittance and reflectance are efficiently retrieved from a comprehensive look-up table pre-computed by a 32-stream DIScrete Ordinates Radiative Transfer (DISORT) model for possible cloud conditions as well as solar and viewing geometries. A resolution analysis is performed to assess the optimal balance between the computational efficiency and accuracy in the development of the look-up table. Model simulations by DISORT and TMYSPEC are used to evaluate the performance of FARMS-NIT under cloudy-sky conditions. Compared to DISORT, FARMS-NIT yields 2–3% uncertainties on average, but it substantially reduces the computational time because of the independent computation of cloud properties and the implementation of the look-up table. In contrast to TMYSPEC, which uses successive steps to empirically compute plane-of-array (POA) irradiances and spectral irradiances, FARMS-NIT directly solves spectral radiances from the radiative transfer equation, which profoundly increases the accuracy in surface irradiances, especially over inclined photovoltaics (PV) panels.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 188〈/p〉 〈p〉Author(s): Sebastijan Seme, Klemen Sredenšek, Bojan Štumberger, Miralem Hadžiselimović〈/p〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Fahad Mateen, Mumtaz Ali, Sae Youn Lee, Sung Hoon Jeong, Min Jae Ko, Sung-Kyu Hong〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, we demonstrate the simultaneous use of carbon quantum dots and organic dyes as highly emissive luminescent material in high performance tandem luminescent solar concentrator (LSC). The top LSC layer is based on carbon quantum dots (CQDs), while the bottom one is based on organic dye. The role of förster resonance energy transfer (FRET) is demonstrated in organic dyes in a bottom LSC. Moreover, the CQDs layer which has the capability to harvest ultraviolet (UV) and near-UV photons acts as a protective layer to improve the photo-stability of the organic dyes contained in bottom waveguide. The electrical measurements showed that the optical conversion efficiency (η〈sub〉opt〈/sub〉) and power conversion efficiency (η〈sub〉PCE〈/sub〉) of CQDs based single LSC are 5.62% and 1.03% respectively. While, η〈sub〉opt〈/sub〉, and η〈sub〉PCE〈/sub〉 the dye-LSC are 13.42% and 2.72% respectively. However, in the tandem LSC, overall η〈sub〉opt〈/sub〉 and η〈sub〉PCE〈/sub〉 are 16.32% and 3.2% respectively. Our results showed that tandem structured CQDs and dye based luminescent solar concentrators make the practical use of LSCs more feasible because of the unique properties such as good photostability and high efficiency.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Vladimir Potemkin, Nadezhda Palko, Maria Grishina〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Electronic properties of benzothiadiazole (BTD) unit containing dyes adsorbed on TiO〈sub〉2〈/sub〉 nano-particles have been estimated using Quantum Theory of Atoms in Molecules (QTAIM). We found that short circuit photocurrent density 〈em〉J〈sub〉sc〈/sub〉〈/em〉 and open circuit photovoltage 〈em〉V〈sub〉oc〈/sub〉〈/em〉 of the studied DSSCs are well related to the electronic properties of dyes, namely charges of BTD atomic basins of nitrogens, summary isodensity surface area and summary volume of hydrogen basins. Analysis of deviations of predicted and observed photovoltaic properties allowed to reveal device fabrication details influencing positively and negatively on device efficiency. Found relationships have been used for design of new promising dyes and recommendation of the better fabrication details of DSSCs with significantly higher photovoltaic properties as compared to the studied and published. For newly designed metal-free BTD-unit containing dyes, 〈em〉J〈sub〉sc〈/sub〉〈/em〉 is expected to reach 20.7–25.8 mA/cm〈sup〉2〈/sup〉, 〈em〉V〈sub〉oc〈/sub〉〈/em〉 – 0.858–1.029 V and power conversion efficiency 〈em〉η〈/em〉 – 10.6–16.3%.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0038092X1930828X-ga1.jpg" width="402" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 188〈/p〉 〈p〉Author(s): Christian Camus, Pascal Offermann, Martin Weissmann, Claudia Buerhop, Jens Hauch, Christoph J. Brabec〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This work demonstrates the capability of meteorological reanalysis data for estimating mechanical stresses due to wind gusts on photovoltaic modules. Besides the immediate power loss caused by the inactive solar cell areas within the module, the influence of cracks induced by such mechanical loads on the ageing and degradation behavior of PV modules is in the focus of current PV reliability research. To choose and/or design the optimum module for a given deployment site at the most economical cost, the mechanical loads the module will be exposed to during its service life need to be estimated. Hence, this paper introduces a new methodology for assessing and deducing site-specific mechanical load scenarios which are expected to be imposed on photovoltaic modules by wind gusts for a given location. The approach presented here is based on the linear calibration of meteorological reanalysis data with publicly available and standardized high-quality surface weather station data of local weather services. In this fashion, site-specific mechanical load scenarios can be deduced for virtually any site covered by the respective reanalysis data set. These scenarios can be used for developing site-specific module qualification tests, thereby providing a methodology enabling climate-specific module designs or specifications. This methodology can also be transferred to virtually any location and other climate and weather parameters such as snow loads, UV dose, etc. Hence a complete assessment of all weather-related degradation scenarios could be deduced eventually.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉(a) Comparison of wind gust data collected at a DWD station in Dresden and data obtained from ERA interim and COSMO reanalysis data. (b) Electroluminescence image of a photovoltaic module damaged by mechanical loads. Black areas comprise electrically weakly connected areas which cannot contribute to power production anymore and result from the damage caused by the load. (c) Mechanical load set up at the ZAE Bayern, which can be used for simulating wind and snow loads with simultaneous detection of the generation and evolution of solar cell cracks in-situ by means of electroluminescence.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0038092X19306516-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 188〈/p〉 〈p〉Author(s): A.A. Yousefi, A.R. Mohebbi, S. Falahdoost Moghadam, S.A. Poursamar, L. Hao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present work, reports on combination of precise positioning ability of 3D printers with near field electro spinning (NFES) as a low-cost and scalable approach to generate well-aligned, evenly distributed microfiber mask upon flexible substrates coated with metal thin film. Using a combination of annealing thermal treatment and the wet chemical etching of metal layer a flexible transparent electrode is prepared. Using this high speed and large-area printing technique we can overcome the drawbacks of conventional electrospinning such as fiber structural inhomogeneity, random orientation, and non-reproducible results. In addition, the application of more complicated and expensive methods such as lithography or e-beam lithography or nanoimprint lithography can be avoided using this technique. The most important advantage of the reported fabrication method relative to electro-spinning process is the ability to have a special control on the distribution pattern of the electrodes on the surface which can lead to better control over the ratio of conductivity and transparency of the surface.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0038092X19306619-ga1.jpg" width="359" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): R. Fazai, K. Abodayeh, M. Mansouri, M. Trabelsi, H. Nounou, M. Nounou, G.E. Georghiou〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, we consider a machine learning approach merged with statistical testing hypothesis for enhanced fault detection performance in photovoltaic (PV) systems. The developed method makes use of a machine learning based Gaussian process regression (GPR) technique as a modeling framework, while a generalized likelihood ratio test (GLRT) chart is applied to detect PV system faults. The developed GPR-based GLRT approach is assessed using simulated and real PV data through monitoring the key PV system variables (current, voltage, and power). The computation time, missed detection rate (MDR), and false alarm rate (FAR) are computed to evaluate the fault detection performance of the proposed approach.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Zhiyong Liu, Ning Wang, Weiliang Zheng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉One of the challenges facing the fabrication of high-performance conventional structure polymer solar cells (PSCs) is the development of new interface materials that have better air stability and charge carrier collection and transport ability. In this study, the mixture thin films of polyethylenimine ethoxylated (PEIE) and TiO〈sub〉X〈/sub〉 are developed as the electron extraction layer (EEL) and Ag as the cathode for the application in PSCs, replacing the Ca/Al composite cathode. Ultraviolet photoelectron spectroscopy (UPS) and space-charge-limited current (SCLC) measurements demonstrate that PEIE:TiO〈sub〉X〈/sub〉/Ag shows appropriate energy levels, substantially reduced barrier potential, weakened charge carrier recombination and enhanced electron mobility. As a result, the PEIE:TiO〈sub〉X〈/sub〉-based PSCs demonstrate not only an enhanced power conversion efficiency (PCE) of 10.94% but also the photovoltaic performance insensitive to the storage time, yielding an aged PCE that is 92% of the fresh PCE. This result can be further explained by the dependence of the charge carrier mobility on storage time. Our work suggests exploiting the PEIE:TiO〈sub〉X〈/sub〉/Ag composite thin films as the composite cathode replacing Ca/Al thin films for successfully enhancing the photovoltaic performance and improving the stability of PSCs.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Ahmad Azmin Mohamad〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The electrolyte is a critical component of dye-sensitised solar cells (DSSCs). Among them, quasi-solid state (QSS) electrolytes are considered as one of the most prospective substitutes for liquid electrolytes to DSSCs. To entirely understand and optimise the performance and stability of QSS, comprehensive characterisation is needed to design new materials, comprehend and optimise the QSS. This review summarises the characterisations of QSS beginning from 2010. Emphasis is placed on the physical characterisations such as viscosity, morphology, thermal, infrared spectroscopy, nuclear magnetic resonance, Raman, ultraviolet-visible, and X-ray diffraction. All parts of the characterisation process are divided into the introduction, the objective of testing, main outcomes and finally, the selected examples. A summary of recent and important measurements on QSS are mentioned at the end.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Shuijia Li, Wenyin Gong, Xuesong Yan, Chengyu Hu, Danyu Bai, Ling Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Parameter estimation of photovoltaic (PV) models plays an important role in the simulation, evaluation, and control of PV systems. In the past decade, although many meta-heuristic methods have been devoted to parameter estimation of PV models and achieved satisfactory results, they may suffer from consuming large computational resources to get promising performance. In order to fast and accurately estimate the parameters of PV models, in this paper, a memetic adaptive differential evolution, namely MADE, is developed. The proposed MADE can be featured as: (i) the success-history based adaptive differential evolution is used for the global search; (ii) the Nelder-Mead simplex method is employed for the local search to refine the solution; and (iii) the ranking-based elimination strategy is proposed to maintain the promising solutions in the external archive. To verify the performance of our approach, it is applied to estimate the unknown parameters of different PV models, 〈em〉i.e.,〈/em〉 the single diode model, the double diode model, and the PV module. Experimental results obtained by MADE are compared with several state-of-the-art methods reported in the literature. Comparison analysis demonstrates that the proposed MADE exhibits remarkable performance on accuracy and reliability. It also consumes less computational resources than other compared methods.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 188〈/p〉 〈p〉Author(s): Hyeon-Seok Lee, Bongkoo Kang, Wook-Sung Kim, Sang-Jin Yoon〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper describes a boost half-bridge DC-DC converter for photovoltaic system that reduces the input voltage and current ripples by using a 1:1 transformer and an auxiliary capacitor. The 1:1 transformer replaces the boost inductor in a previous boost half-bridge converter. The auxiliary capacitor is connected serially to the secondary coil of the 1:1 transformer, and resonates with the leakage inductance of the 1:1 transformer. The input voltage and current ripples are reduced by setting the switching frequency equal to the resonance frequency between the auxiliary capacitor and the leakage inductance, and by coupling the resonance current to the primary coil of the 1:1 transformer. The proposed converter had input voltage ripple less than 0.2 V〈sub〉p.p〈/sub〉, input current ripple less than 0.81 A〈sub〉p.p〈/sub〉, and power-conversion efficiency higher than 94.5% when the converter was operated at input voltage of 30–50 V, output voltage of 400 V, output power of 30–300 W, and switching frequency of 46 kHz. These experimental results show that the proposed converter is well suited for photovoltaic micro-inverter applications that require a small input capacitor, low input voltage, high input current, high output voltage, and high power-conversion efficiency.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0038092X19306450-ga1.jpg" width="284" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 188〈/p〉 〈p〉Author(s): Mohammad A. Alim, Zhong Tao, Md Kamrul Hassan, Ataur Rahman, Baolin Wang, Chunwei Zhang, Bijan Samali〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Buildings consume a large quantity of energy. In May 2010, the European Union (EU) reported that around 40% of their energy consumption was related to building sectors, which is similar to the proportion of 39% in the United States. In Australia, buildings count 20% of its total energy consumption. Experts across the globe have been working in the development of new technologies, which not only reduce the building energy consumption but also harness energy from renewable sources. Building integrated photovoltaic (BIPV) system is one of the most popular techniques towards constructing a net-zero energy building through the utilisation of solar energy. In this review, we focus on the BIPV applications in Australia, where BIPV has not been prevailed as widely as might be expected despite the high solar irradiation in the country. This paper discusses recent advancements in BIPV systems and challenges that Australia is facing in order to adopt this technology. In addition, the current carbon emission issues in Australia are presented to build awareness among people, which will contribute towards adopting this technology. A range of experimental and numerical studies have been reviewed to identify the effectiveness of BIPV on building performances. This study also reports on the sustainability and economic feasibility of BIPV systems in terms of energy payback time and economical payback time, respectively. Based on this review, it is argued that BIPV is technically and economically feasible for Australia and its implementation might be started with solar roof tiles.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Yanli Song, Mingyin Zou, Xin Chen, Junyu Deng, Tao Du〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A model that could ensure the lowest energy consumption and optimize all possible performance parameters simultaneously was proposed based on experiments that run the ground source heat pump passive heat supply tower at given conditions. By studying the relationship between the range, approach, tower characteristic ratio, effectiveness, air condensation rate of the passive heat supply tower and water-air ratio, a multi-objective optimization model and its objective function are proposed. With the target of reducing power consumption to the greatest extent, the unconstrained optimization of all objective functions was performed using the Elite Non-dominated Sorting Genetic Algorithm (NSGA-II), in which five performance parameters were adopted to estimate the air flow via decision making at a given water flow rate. The results show that the heat transfer is independent of the water flow. An optimal water-air ratio of 0.48 is determined according to comprehensive analysis of the parameter weights. Under constant water flow rate, the optimal air flow rate and water flow rate is 108.5 g/s and 47.2 g/s, respectively, as observed by comparing the Decision Matrix Score (DMS) value. According to the multi-objective optimization method and the NSGA-II algorithm, optimizations of the performance of supplementary tower are more effective and reasonable as the Decision Making Matrix (DMM) can reasonably allocate parameters expected by users to occupy a larger weight.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Matteo Valentini, Claudia Malerba, Luca Serenelli, Massimo Izzi, Enrico Salza, Mario Tucci, Alberto Mittiga〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Earth abundant Cu〈sub〉2〈/sub〉ZnSnS〈sub〉4〈/sub〉 (CZTS) semiconductor can find a promising application as wide-bandgap top cell absorber in CZTS/Silicon tandem devices. The coupling between the top and the bottom cells in a monolithic device requires the development of a proper intermediate connection able to ensure: (i) high transparency in the infrared region (ii) good electric contacts and (iii) good chemical stability under thermal treatments used for the CZTS growth, in order to prevent elements interdiffusion and silicon degradation. To this purpose, some multilayered structures based on MoS〈sub〉2〈/sub〉 and different Transparent Conductive Oxides (TCOs) were tested as intermediate connection in CZTS/Silicon tandem devices. The first working monolithic tandem cell, with open circuit voltage of about 950 mV and an efficiency of 3.5%, was obtained using a MoS〈sub〉2〈/sub〉/FTO/ZnO trilayer structure as intermediate contact between the top and the bottom cells. Some limiting factors of this device were addressed and investigated in order to increase the tandem cell efficiency.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Yujie Wu, Jérôme H. Kämpf, Jean-Louis Scartezzini〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The bidirectional transmittance distribution function (BTDF), which is used to characterize the light transmission of a complex fenestration system (CFS), commonly involves bulky volume of data that can be a challenge to data storage and transmission in lighting simulation tools and on compact platforms. This paper introduces a compression scheme that is based on planar wavelet transforms with three levels of decomposition to efficiently compress the BTDF data of CFSs and maintain fidelity in daylighting simulation. The root-mean-square error (RMSE) and transmittance error (TE) of compressed medium-resolution BTDF data using three different wavelet bases were evaluated for five different CFS samples at various compression ratio. Based on the results, the generic error from compression did not exceed 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"〉〈mrow〉〈mn〉20〈/mn〉〈mo〉%〈/mo〉〈/mrow〉〈/math〉 with CDF9.7 basis for compression ratio up to 200. In the case of rendering an image of a scene in which a CFS was installed at the upper daylighting section of an unilateral façade, errors began to be noticeable at a compression ratio above 70. The uniformity factor 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.svg"〉〈mrow〉〈mi mathvariant="normal"〉g〈/mi〉〈mn〉1〈/mn〉〈/mrow〉〈/math〉 was discovered to be relatively sensitive to compression (below 15% error), while the average horizontal illuminance and daylight glare probability (below 10% error) were immune to compression ratio below 100. Compression was also evaluated for a high-resolution BTDF data of external Venetian blinds in the simulation of work-plane illuminance (WPI). With a HDR imaging technique based sky luminance map, the WPI simulation had unnoticeable errors for compressed BTDF data within a compression ratio of 100.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Rok Stropnik, Rok Koželj, Eva Zavrl, Uroš Stritih〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Prudent and efficient utilization of renewable energy sources is needed in order to achieve clean energy transition. Since energy use in buildings represents around 40% of total energy use in European Union the reduction of energy use in this sector is most definitely needed. One of the great challenges in this sector represents retrofit of residential buildings where 〈sup〉3〈/sup〉/〈sub〉4〈/sub〉 of buildings in Europe are residential. To reduce energy consumption and increase the use of renewables in existing residential buildings to achieve nearly zero energy buildings (nZEB) a holistic approach of retrofit with interconnected technological system is needed. In the first part of this paper the nZEB and thermal energy storage are introduced for further implementation of the phase change material (PCM) into storage tank. Furthermore energy toolkit based on the synergetic interaction between technologies integrated in the system for holistic retrofit of residential buildings, which is under development within HEART project (HORIZON 2020), is presented. In this project step towards self-sufficient heating and cooling of building is made with increase in on-site consumption of self-produced energy from solar energy and interconnection between PV, electrical storage, heat pump, thermal energy storage, fan coil heat pump, cloud based decision support and building energy management system. With such a smart energy system the almost zero-energy buildings will be possible to decrease energy use in residential sector. Improvement of sensible thermal energy storage with implemented cylindrical modules filled with PCM is investigated experimentally. The results from experiment show that thermal energy storage unit with integrated modules filled with PCM can supply desired level of water temperature for longer period of time. The advantage of PCM in thermal energy storage is in applications that needs narrow temperature range of supplying and storing thermal energy what is the subject matter of consideration in the case of HEART project.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 189〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Magd N. DinAli, Ibrahim Dincer〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A novel renewable energy based integrated system for dimethyl-ether (DME) production and electricity generation is proposed, analyzed thermodynamically and evaluated energetically and exergetically. The DME is produced in a unique way through carbon hydrogenation process to produce pure methanol, and then DME is synthesized from methanol through methanol dehydration process. The hydrogen required for the process is produced using solid oxide steam electrolyzer (SOSE) which is powered by the thermal energy provided by solar heliostat field to generate steam and generate electricity through a steam turbine. The carbon dioxide is captured from steel furnace exhaust gas using chemical absorption method. The present system is modeled and simulated using both Aspen plus process simulation software and Engineering Equation Solver (EES), and assessed according to energy and exergy performance evaluations. The overall system energy and exergy efficiencies are then found to be 28.75% and 32.54% respectively.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 188〈/p〉 〈p〉Author(s): Y. Chaibi, A. Allouhi, M. Malvoni, M. Salhi, R. Saadani〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Various works investigated different photovoltaic (PV) cell equivalent-circuit models and several techniques were proposed to extract their unknown parameters. The present paper analyzes the current/voltage (I-V) characteristics for Si-crystalline PV modules under non-standard conditions of irradiance and temperature, by using single-diode and double-diode models. The Chaibi and Ishaque methods are employed to determine the parameters for each equivalent-circuit model. Then, the I-V curves provided by the manufacturers and the calculated I-V characteristics are compared at different levels of irradiance and temperature. The comparison suggests prioritizing one of the two equivalent-circuit models according to the prevailing meteorological inputs. As such, a hybrid approach is proposed in order to select the most appropriate model depending on the relevant climatic conditions. The presented approach accuracy is evaluated using real weather data of two PV plants located in two different climatic zones (Mediterranean and Semi-Continental). Results show that the double-diode model is more reliable for low-irradiance levels; however, the single-diode model performs well with low-temperature fluctuations. An error reduction of 53.93% and 21.04% can be reached for the cloudy weather and for the sunny days, respectively. Accordingly, this approach can be easily implemented as a computing tool to achieve more accurate prediction in the PV systems simulations.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 188〈/p〉 〈p〉Author(s): K. Murugaperumal, P. Ajay D Vimal Raj〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper validates the optimal design and techno-economic feasibility of hybrid renewable energy system (HRES) for rural area electrifying applications. Plan to a design of improved performance electrification system through village owned renewable resources, such as solar irradiations, wind speed and bio mass etc. The selected HRE system has to meet out electrical needs in optimum performance manner. Hear conducted a case study on remote village Korkadu is located in Union Territory of Pondicherry, India. The expected village demand of 179.32 Kwh/day and peak of 19.56 Kw was met with proposed HRE structure, which is consists of solar PV array, wind turbine, Bio mass power generator and Battery backup system in effectively. Load growth of the village was predicted through artificial neural network (ANN-BP) feed-back propagation and Levenberg-Marguardt (LM) data training optimum technique. Encounter the optimum performance of different HRE configuration was evaluated over by HOMER software. System’s economic dispatch was analysed through various dispatch strategy and come across the proposing companied dispatch strategy has more economical and performance benefits as total NPC of system as INR 1.21 million, one unit energy generation cost as INR 13.71 and annual battery throughput as 36.648 KWh/yr. This study also expresses the comparison analysis between proposed HRES structure performance with basic utility grid extension. The consequence of the proposed work shows the HRES in remote location can be a cost effective solution for sustainable development of rural regions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Mustapha Errouha, Aziz Derouich, Babak Nahid-Mobarakeh, Saad Motahhir, Abdelaziz El Ghzizal〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper presents a simple standalone photovoltaic (PV) water pumping system (PVWPS) based on an induction motor (IM) without the use of chemical energy storage. The aim of this paper is improving the control performance of pumping system. The proposed method is based on an indirect field-oriented control (IFOC) which consists of operating the motor at optimum flux by minimizing the induction motor losses. Perturb ad observe (P&O) algorithm is used to extract the maximum possible power from the PV panel. The performance of the proposed approach is proved by real time implementation using a dSpace DS1005 system and compared with conventional IFOC without losses minimization. Results show that using the proposed method, the losses are reduced and the efficiency is increased by 12%, 2.5% and 5% under 375 W/m〈sup〉2〈/sup〉, 750 W/m〈sup〉2〈/sup〉 and daily profile respectively.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Miroslav Kocifaj, Jaromír Petržala〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Light diffusing modules with improved optical properties could usefully facilitate the quest to achieve smart daylight harvesting in office buildings without detrimentally affecting visual comfort in building interiors. However, direct sunlight and sky light may cause discomfort glare. And a use of optically dense diffusers to reduce this effect and produce more uniform indoor light fields is not an efficient solution because of a concomitant loss of luminous energy. Hence, the need for more environment and people sensitive solutions is pressing in order to improve combined optical efficiency, efficacy and ergonomy of work-place luminance.〈/p〉 〈p〉That design aspiration is addressed and involves semitransparent apertures with the directional distribution of luminous intensity approaching that required. Methods for targeted shaping of an illuminance pattern are certainly advantageous for visual comfort, while supporting more demanding visual work and more flexible visual orientation. The numerical experiments we have conducted have proved that retrieval of optimum optical properties of a diffusing medium is possible through minimizing the differences between theoretical and required illuminance patterns. The inverse transform has been successfully validated for sensitivity, specificity and convergence. Our solution is augmented by the proposal for a possible realization of the diffusing aperture in the form of a particle-doped transparent medium which mimics, thus can personalize, the illuminance patterns desired.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Jitendra Bahadur, Amir H. Ghahremani, Sunil Gupta, Thad Druffel, Mahendra K. Sunkara, Kaushik Pal〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Rapid growth within performance and stability of organic-inorganic halide-based perovskite solar cells (PSCs) has made this emerging photovoltaics a great potential for further research towards successful commercialization. However, two major issues of: (i) 〈em〉Structural ambient stability〈/em〉, and (ii) 〈em〉Toxicity〈/em〉, caused by the presence of Pb content, are the pivotal obstacles for the commercialization of environmental friendly PSC. In this regard, we are introducing a highly ambient stable PSC through the incorporation of barium (Ba) with successful ultrashort annealing through intense pulsed light (IPL). The ambient stability of Ba doped perovskite thin films was explored in the humidity range of 35–68%. The power conversion efficiency (PCE) of fabricated devices were found to be 8.99, 7.39, 6.94, 6.60, 5.98 and 3.82% for pristine, 1, 2, 5, 10, and 20 mol% Ba doping, respectively. Afterwards, fabricated devices were kept in ambient environment under dark for 20 days. With systematic photovoltaic analysis, it was observed that the 2.0 mol% Ba doped PSC exhibited 8.0% efficiency drop (from 6.94 to 6.38%), whereas the PCE of pristine based devices decreased from 8.99 to 2.60%, demonstrating an almost 71.0% drop. Our photovoltaic results demonstrated a great improvement within the ambient stability of PSC without any encapsulation which can indicate Ba doping as highly promising approach for the fabrication of PSC with higher ambient stability.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0038092X19308138-ga1.jpg" width="476" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): A. Vega, V. Valiño, E. Conde, A. Ramos, P. Reina〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The good performance of solar photovoltaic energy facilities implies the previous evaluation of the electrical behaviour of the solar modules used. Among other ways, this evaluation can be done by means of the static voltage-current characteristic (I-V curve), but also through a real-time electrical parameters monitoring. This paper proposes the design of an I-V curve tracer with electronic load. The main advantages of the prototype are its reduced cost, scalability, wireless control and sampling rate. A PIC18F46K80 microprocessor was used for the design and construction of the prototype. The development of an Android app allows the control of the prototype and the data acquisition from any mobile or tablet device. Additionally, the tracer can be configured for a continuous monitoring of the electrical parameters, temperature and irradiance.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Mi Zhong, Wei Zeng, Hua Tang, Long-Xiang Wang, Fu-Sheng Liu, Bin Tang, Qi-Jun Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Using first- principles calculations, we investigate the electronic properties of the inorganic-organic hybrid perovskite CH〈sub〉3〈/sub〉NH〈sub〉3〈/sub〉PbI〈sub〉3〈/sub〉, covering band structures, effective masses and exciton binding energies. For the first time, this study offers a comparison between perovskite polymorphs of CH〈sub〉3〈/sub〉NH〈sub〉3〈/sub〉PbI〈sub〉3〈/sub〉 with GGA and HSE06 functionals. It is verified that the standard DFT-GGA is a reliable methodology for calculating the band gaps of Pb-based perovskites. Effective masses of cubic CH〈sub〉3〈/sub〉NH〈sub〉3〈/sub〉PbI〈sub〉3〈/sub〉 are rather lighter than that of the orthorhombic and tetragonal polymorphs. And this characteristic echoes the lightest effective masses in the cubic CH〈sub〉3〈/sub〉NH〈sub〉3〈/sub〉PbI〈sub〉3〈/sub〉. The reduced mass (0.05 〈em〉m〈/em〉〈sub〉0〈/sub〉) and binding energy (15.9 meV) are obtained for the cubic phase, providing direct evidence for the high efficiency of cubic polymorphs in solar energy applications. Besides, it is found that the phase transformation from orthorhombic to tetragonal phase leads to the reduction of the band gap.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Mohamed Dardir, Mohamed El Mankibi, Fariborz Haghighat, Lubomir Klimes〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Earlier applications of phase change material (PCM)-to-air heat exchangers (PAHXs) reported the insufficient cooling charging energy needed for complete solidification of the PCM in free cooling systems. Also, the prediction of PAHX performance under low airflow regimes is a system limitation for free cooling applications. Besides, the implementation of the long wave thermal radiation cooling concept has not gained much attention in the free cooling design of PAHX units. This paper reports the development of PAHX system for building envelope applications that promotes the thermal radiation loss to the sky during night-time to maximize the cooling potential. A 2D numerical model has been developed considering the PCM thermal behavior, short and long wave radiation, and convection phenomena. New thermal boundaries of long-wave radiation have been proposed between system elements and the sky temperature. In addition, the model considered various forms of convective heat transfer phenomena. The apparent heat capacity method was used to simulate the thermal storage process. Experimentally obtained data and inter-model comparison were used to validate the proposed model. Two full-scale prototypes of the developed PAHX system were designed and tested under real conditions using two different types of PCMs. A parametric analysis was conducted to investigate the system thermal behavior under various air velocity profiles in the air channel and various inlet air temperature conditions. The results indicate that the building envelope integrated PAHX can use the sky radiation as a cooling source.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): P.D. Sreedevi, R. Vidya, P. Ravindran〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Direct band gap semiconductors with high optical absorption, high electrical conductivity, high carrier mobility, low reflectance and low recombination rate of charge carriers are needed for a variety of applications in solar energy conversion and optoelectronics. We have identified three ternary semiconductors Ca〈sub〉3〈/sub〉PN, NaBaP and ZrOS which have direct-band gap and other promising properties for solar energy applications. The prime novelty of this work mainly projects a detailed information on the electronic structure and optical properties for the three materials. From the first principles computational work and analysis, we have found that all the three materials with optimum band gap (~1.52 eV) value are having suitable absorption coefficient, extinction coefficient, optical conductivity and low reflectance in the visible region. Moreover, these materials are found to have low charge carrier effective masses and low recombination rates which can enhance carrier mobility and electrical conductivity. As a result, we will have three best non-silicon based direct band gap materials consisting of earth-abundant and non-toxic elements in the photovoltaic (PV) industry.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Yanqing Wang, Xingze Chen, Junjie Shao, Shihao Pang, Xinlai Xing, Ziyu Dong, Shuang Liu, Zhendong Cui, Xinlian Deng, Chengwu Shi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The synthesis and characterization of a series of hole transporting materials (HTMs) based on carbazole core and dimethoxytriphenylamine (TPA) groups are reported. By modifying the number of TPA components in the HTMs, the influence of the structure of HTMs molecules on the photovoltaic performance of CH〈sub〉3〈/sub〉NH〈sub〉3〈/sub〉PbI〈sub〉3〈/sub〉 perovskite solar cells are investigated. 〈strong〉TPA〈sub〉2〈/sub〉C〈/strong〉, in which two TPA units are incorporated onto the carbazole core, exhibited higher photovoltaic performance than 〈strong〉TPA〈sub〉1〈/sub〉C〈/strong〉, 〈strong〉TPA〈sub〉3〈/sub〉C〈/strong〉 and 〈strong〉TPA〈sub〉4〈/sub〉C〈/strong〉, which contain one, three and four TPAs, respectively. The introduction of TPA group from one to two can improve the device result, however, additional branches introduced to the carbazole core did not led to higher efficiency.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0038092X19308151-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Sabrina N. Rabelo, Tiago F. Paulino, Willian M. Duarte, Antônio A.T. Maia, Luiz Machado〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In a Direct Expansion Solar Assisted Heat Pump (DX-SAHP), a valuable part of the energy is provided from solar radiation. The solar radiation can fluctuate during the day affecting the performance of the system. The impact of a fixed opening in the expansion device on the system performance is not well known, especially for a small-size solar assisted heat pump. In this context, it is presented an experimental analysis of the influence of the expansion valve opening on the performance of a CO〈sub〉2〈/sub〉 DX-SAHP. Experimental tests were carried out considering different solar radiations conditions. The value of the expansion device opening that leads to the maximum COP was almost the same, regardless of solar radiation. In consequence, it was concluded that, for a small CO〈sub〉2〈/sub〉 DX-SAHP, using a basic cycle configuration a static expansion device as a capillary tube would be suitable, reducing the costs of this equipment.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Vikash Kumar〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Thermal and thermohydraulic performance characteristics for 3-sides concave dimple roughened collector has been investigated and presented here. The geometrical parameter of roughness element covers relative dimple pitch, height and depth 8–15, 0.018–0.045 and 1–2 respectively along with flow Reynolds number 2500–13,500. Thermal performance of artificially roughened SAH doesn’t include a frictional loss that is generated while the air is propelled through the roughened ducts. Three sides roughened ducts have high thermal efficiency compared to 1-side roughened duct but that hike should not come at the cost of tremendous rise in frictional losses. The present investigation is aimed at determining the optimum roughness parameters at which maximum possible efficiency is obtained at minimum frictional losses. The optimum roughness parameter yielding the maximum thermal efficiency is ‘p/e’ = 12, ‘e/D〈sub〉h〈/sub〉’ = 0.036 & ‘e/d’ = 1.5 for both ducts. 3-sides concave dimple roughened SAH were having 44–67% more thermal efficiency than 1-side roughened duct under similar flow condition. Maximum effective (thermohydraulic) efficiency at varying ‘e/D〈sub〉h〈/sub〉’ obtained was 0.78 and 0.49 and that at varying ‘p/e’ obtained was 0.74 and 0.47 in the case of 3-sides and 1-side roughened ducts respectively.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Hai Yang, Jingge Song, Boshu He, Guangchao Ding〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The charging characteristics of a cylindrical Encapsulated Phase Change Material (EPCM) capsule with embedded heat pipe (HP) is investigated numerically for latent heat storage. For the heat pipe-assisted capsule, called EPCM-HP unit, a 3-D transient thermal storage model is implemented combining Lumped Thermal Resistance Network (LTRN) as the heat pipe model with conventional enthalpy-porosity approach as phase change model. The effects of flow conditions (laminar and turbulent), heat pipe condenser length and types of HTFs (Therminol/VP-1 and air) on thermal characteristics of the EPCM-HP unit are simulated, respectively. Results show that embedding heat pipe can reduce the total charging time by 11.26%. The charging process under turbulent flow is more than 10 times faster than that under laminar flow. Increasing the condenser length of heat pipe cannot effectively reduce the charging time of ECPM-HP unit since the thermal resistance also increases and the starting time of convection is delayed. The results also reveal that Therminol/VP-1 (high 〈em〉Pr〈/em〉 HTFs) can charge thermal energy faster than air (low 〈em〉Pr〈/em〉 HTFs), while the enhancement effect of heat pipe is more significant when using air (low 〈em〉Pr〈/em〉 HTFs).〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Thomas Baumann, Hartmut Nussbaumer, Markus Klenk, Andreas Dreisiebner, Fabian Carigiet, Franz Baumgartner〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Dependent on the specific conditions flat roofs can be well suited for the installation of large photovoltaic systems in urban areas. For urban designers also other aspects, such as the insulation of buildings, cooling, air purification and water retention play an important role besides the ecological energy generation. The combination of photovoltaics and roof greening can therefore be an interesting fusion. It combines the advantages of a green roof with the local electrical energy production at the place of consumption.〈/p〉 〈p〉However, using a conventional photovoltaic system with tilted modules in south or east-west direction on a green roof causes problems, as typical low tilt angels and high ground coverage rates result in an almost complete coverage of the roof surface. Plants, growing in between the covered areas provoke undesirable shading of the collector surface. Only a frequent maintenance procedure, complicated by dense PV system layouts, can avoid a reduction of the energy yield in the course of time.〈/p〉 〈p〉Vertically mounted specially designed bifacial modules are an option to realize photovoltaic power generation in combination with a functional green roof at low maintenance costs. In this paper, we report on the layout and the energy yield of a corresponding system. Custom-made bifacial modules with 20 cells were produced and vertically installed in landscape orientation. The narrow layout of the modules lowers the wind load and reduces the visibility. The enhanced power in the morning and evening of vertically east-west installed modules can additionally lead to higher self-consumptions rates.〈/p〉 〈p〉Despite having some shading and undergrounds with albedo factors of less than 0.2, the bifacial installation with a rated power of 9.09 kWp achieved a specific yield of the 942 kWh/kWp in one year (11.08.2017–10.08.2018). This is close to typical values of 1000 kWh/kWp achieved for south-facing PV systems in the same region.〈/p〉 〈p〉The impact of the greening on the albedo and the system performance is investigated in more detail with two smaller sub-systems. The energy yields of the two bifacial sub-systems are compared to a monofacial, south-facing reference module. The use of silver-leaved plants in this system resulted in higher albedo values and a more resilient roof greening.〈/p〉 〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0038092X19307844-ga1.jpg" width="300" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Hanbing Ling, Rui Zhang, Xiaoqin Ye, Zhiyue Wen, Jiangbin Xia, Xing Lu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Here, an organic-inorganic hybrid thin film of PEDOT/V〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 complex was successfully obtained via an in-situ synthesis method. In detail, PEDOT buffer layer was prepared by in-situ oxidative polymerization. Then, a layer of V〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 nanoparticles was deposited on it. V〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 nanoparticles can closely combine with PEDOT and modifying the surface defects of PEDOT. For the control polymer solar cells (PSCs) with a PEDOT:PSS hole transport layer (HTL), a power conversion efficiency (PCE) of 3.50% is obtained. Encouragingly, a higher PCE of 3.76% is achieved for the cell using the as-prepared PEDOT/V〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 as the HTL, which increased by 8% than that of the control device. Furthermore, the devices with PEDOT/V〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 show a better stability than the control devices using PEDOT:PSS as HTL. The results indicate that PEDOT/V〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 is an excellent HTL for efficient and stable PSCs.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Nelson Sommerfeldt, Hatef Madani〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The electrification of buildings is a promising pathway to the decarbonization of cities. This is a parametric study of the technical and economic performance of ground source heat pump (GSHP) systems with series connected solar PV/thermal (PVT) collectors. The focus is on multi-family houses (MFH) in the heating dominated climate of Sweden, where land restrictions for boreholes or noise restrictions on air heat exchangers limit the heat pump market. System efficiency and lifecycle cost results are generated using a holistic and detailed systems model in TRNSYS with 20 year simulations. The results show that PVT can reduce borehole length by 18% or spacing by 50% while maintaining an equivalent seasonal performance factor to systems without PVT. The cost for PVT+GSHP systems is higher than a traditionally designed PV+GSHP, however this does not take into account the value of the land area saved by PVT, which can be up to 89%. The reduction in land enabled by PVT has the potential to increase penetration of GSHP in MFH and promote solar energy diffusion in high latitude markets.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0038092X19307510-ga1.jpg" width="334" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 189〈/p〉 〈p〉Author(s): Jamie M. Bright〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Solcast (〈a href="https://solcast.com/" target="_blank"〉https://solcast.com/〈/a〉) is a global solar forecasting and historical solar irradiance data company. Their datasets are important to the scientific community as substantial amounts of historical data is made freely available to researchers. Solcast’s hourly averages and sub-hourly instantaneous (10/15-min) global horizontal irradiance (GHI) estimates are validated at 48 BSRN ground stations that contain 1,014,792 valid hourly average measurements and 2,932,976 valid instantaneous measurements. The data are validated globally and across four climates under clear-sky, clouded-sky and all-sky periods, repeated for ‘all zenith angles’ (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si17.svg"〉〈mrow〉〈mi〉θ〈/mi〉〈mo〉_〈/mo〉〈mi〉z〈/mi〉〈mo〉〈〈/mo〉〈mn〉85〈/mn〉〈mi〉°〈/mi〉〈/mrow〉〈/math〉) and high-sun zenith angles (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si18.svg"〉〈mrow〉〈mi〉θ〈/mi〉〈mo〉_〈/mo〉〈mi〉z〈/mi〉〈mo〉〈〈/mo〉〈mn〉50〈/mn〉〈mi〉°〈/mi〉〈/mrow〉〈/math〉). A site-by-site validation is also performed for both hourly and instantaneous datasets. All validations and recommendations are impartial and unbiased.〈/p〉 〈p〉The hourly dataset validated similarly for both zenith angle scenarios, which is remarkable due to the added complexities at low-sun angles. In terms of rRMSE, the global performances of hourly GHI under clear-sky, clouded-sky and all-sky were 3.4%, 25.6% and 16.9%, respectively. With each ground station equally weighted, the overall bias was 0.33%, and standard deviation of biases at 1.7%. Solcast’s instantaneous GHI product validations were at times similar to the hourly validations though is naturally harder with increasing temporal resolution.〈/p〉 〈p〉The historical datasets from Solcast are found to be of good quality, thus, they are recommended for use by researchers. Identified areas for improvement herein will guide future developments of Solcast’s methodology.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 189〈/p〉 〈p〉Author(s): Riyas Subair, Diego Di Girolamo, Michal Bodik, Vojtech Nadazdy, Bo Li, Peter Nadazdy, Zoran Markovic, Monika Benkovicova, Juraj Chlpik, Mario Kotlar, Yuriy Halahovets, Peter Siffalovic, Matej Jergel, Jianjun Tian, Francesca Brunetti, Eva Majkova〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The doping effect of carbon nanodots (CNDs) in the PC〈sub〉61〈/sub〉BM electron-transport layer on the performance of inverted planar MAPbI〈sub〉3〈/sub〉 perovskite solar cells (PSCs) having two different kinds of the hole-transport layer, namely organic PEDOT:PSS and inorganic NiO〈sub〉x〈/sub〉, was investigated. The CH〈sub〉3〈/sub〉NH〈sub〉3〈/sub〉PbI〈sub〉3〈/sub〉 perovskite layer was deposited in air at 35% humidity. An average 11% and 12% enhancement of the power conversion efficiency (〈em〉PCE〈/em〉) was achieved for 1 wt% CNDs doping in the PSCs with PEDOT:PSS and NiO〈sub〉x〈/sub〉, respectively. This improvement is attributed to high electron density of CNDs resulting in a triple increase of the electrical conductivity of the PC〈sub〉61〈/sub〉BM layer and passivation of the perovskite/PC〈sub〉61〈/sub〉BM interface that is reflected by an increase of the open-circuit voltage. In line with this, parallel resistance and fill factor of the PSCs are also improved. Moreover, the energy-resolved electrochemical impedance spectroscopy revealed additional free-charge carriers in the PC〈sub〉61〈/sub〉BM layer generated under illumination that were detected via the polaron states formation in the band gap with positive effect on the short-circuit current. All these factors contribute to the PCE improvement. Stability tests of the PSC with PEDOT:PSS under a continuous 24 hour 1.5 AM illumination showed a five times smaller final PCE decrease for the 1 wt% CNDs doping of the PC〈sub〉61〈/sub〉BM layer comparing to the undoped counterpart. The passivation effect of CNDs, namely electron filling the traps formed by the photo-dimerization and photo-oxidation of PC〈sub〉61〈/sub〉BM molecules, is responsible for this remarkable improvement of the short-term stability.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 189〈/p〉 〈p〉Author(s): Gilberto Figueiredo, Marcelo Pinho Almeida, Alex R.A. Manito, Roberto Zilles〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The detection and the analysis of in field early degradation of a grid connected photovoltaic system located at the Institute of Energy and Environment of the University of São Paulo (IEE-USP) are presented. The PV generator is composed by 260 W photovoltaic (PV) modules made of N-type monocrystalline silicon PV cells. Loss of generation capability during the second year of operation was revealed by the PV system’s SCADA. Subsequent measurements showed similarities with strong ageing degradation mechanisms and Potential Induced Degradation (PID) was also detected.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 189〈/p〉 〈p〉Author(s): Xiao-Lin Wang, Jia-Ming Zhao, Nuo Chen, Na-Qing Cai, Xiao Zhang, Xiao-Lei Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The reliable periodic density functional theory calculations have been carried out to investigate the diverse sensitization effects of five different additives, Guanidinium thiocyanate (GNCS), 3-Methoxypropionitrile (MPN), 〈em〉N〈/em〉-Butylbenzimidazole (NBB), 〈em〉N〈/em〉-Methylbenzimidazole (NMB) and 4-〈em〉tert〈/em〉-butylpyridine (TBP), on the electronic structures of TiO〈sub〉2〈/sub〉 anatase (1 0 1), (1 0 0) and (0 0 1) surfaces in vacuum and acetonitrile conditions, respectively. The complex microscopic essence of sensitization effect induced by additive can be revealed successfully by an in-depth interpretation on the inherent relations of the open-circuit photovoltage with fundamental electronic properties, i.e. Fermi energy, molecular orbital, dipole moment, electrostatic potential and work function. There is an explicit inverse correlation between the change of energy gap (〈em〉E〈/em〉〈sub〉△(LUMO-HOMO)〈/sub〉) and Fermi energy shift (〈em〉E〈/em〉〈sub〉△Fermi〈/sub〉) through the comparison among different additives adsorption under the same conditions of surface and solvent, namely, the smaller 〈em〉E〈/em〉〈sub〉△(LUMO-HOMO)〈/sub〉 corresponds to the bigger 〈em〉E〈/em〉〈sub〉△Fermi〈/sub〉. The more positive 〈em〉E〈/em〉〈sub〉△Fermi〈/sub〉 (i.e. negative potential shift) results in the higher open-circuit photovoltage of dye-sensitized solar cells. Moreover, the 〈em〉E〈/em〉〈sub〉△(LUMO-HOMO)〈/sub〉 is in the order TiO〈sub〉2〈/sub〉 (1 0 1) 〈 (1 0 0) 〈 (0 0 1) for every additive adsorption, exactly opposite to the order of surface stability. Total dipole moment is more suitable than its component normal to the TiO〈sub〉2〈/sub〉 surface for measuring the sensitization performances of different species of additives. The smaller work function contributes to the bigger 〈em〉E〈/em〉〈sub〉△Fermi〈/sub〉 of the sensitized nanocrystalline TiO〈sub〉2〈/sub〉. The influences of acetonitrile on the sensitization performances of five additives are diversified, better for MPN, NBB and NMB, general for GNCS, and the worst for TBP.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0038092X19307352-ga1.jpg" width="276" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 189〈/p〉 〈p〉Author(s): Meruyert Sovetova, Shazim Ali Memon, Jong Kim〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Researchers have used phase change materials to reduce energy cost, dependency on fossil fuels and make the buildings energy efficient. However, the following issues have not been addressed yet. (a) How PCM influence the thermal performance and energy efficiency of PCM integrated buildings with local construction details in hot desert climate? (b) How energy savings in PCM integrated buildings are related to meteorological factors such as wind speed, temperature and relative humidity? (c) What is the economic and environmental impact of PCM integrated buildings located in BWh climate? Hence, the thermal performance and energy efficiency performance of PCM integrated residential building located in eight different cities (Abu-Dhabi, Dubai, Faisalabad, Mecca, Jodhpur, Nouakchott, Cairo and Biskra) from hot desert climate zone was evaluated with thirteen different PCMs in EnergyPlus. Test results showed that the optimum PCMs were able to reduce the temperature fluctuations and the maximum temperature reduced by up to 2.04 °C. Except for Cairo and Biskra, the best PCM were close to the cooling set point suggesting that in hot desert climate, PCM with higher melting points perform better. For selected cities, the energy consumption reduction varied from 17.97 to 34.26% while for a given volume of PCM, energy efficiency increased with the increase in the surface area and decrease in the thickness of PCM layer. From multiple regression analysis, the equation describing the dependency of energy saving on meteorological parameters was obtained. Conclusively, economical and environmental aspects of the incorporation of PCM in a residential building located in a hot desert climate were discussed.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 189〈/p〉 〈p〉Author(s): E. Saloux, M. Sorin, A. Teyssedou〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper tackles the exergo-economic assessment of two integrated energy systems that allow the building heating demand to be achieved; a solar assisted heat pump using ice storage and an ambient air heat pump with photovoltaic panels. These systems are firstly described and their performance is discussed for various surfaces of solar collectors and photovoltaic panels. To this purpose, the total electrical energy consumption and the total cost are estimated while the total exergy destruction is divided according to renewable and non-renewable energy flows. This latter, which is really paid by the user, then serves as the exergy performance indicator. The ambient air heat pump with photovoltaic panels is found as the optimal solution from energy and economic perspectives while the solar assisted heat pump using ice storage provides the best exergy performance. To help analyze results, the system performance is illustrated by using an exergy diagram, where energy terms are shown on the abscise axis and energy quality factors are on the ordinate axis. This 2-D graphical representation, which can consider the results from dynamic analyses, helps understand the system operation and performance, and reveals the sources (components), the reasons (energy loss and/or energy potential factor degradation) and the nature (renewable, non-renewable flows) of irreversibility.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Yong Tang, Jihua Zhang, Xiangli Zhong, Qianjin Wang, Heng Zhang, Chuanlai Ren, Jinbin Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Over the past few years, the excellent photoelectric properties of perovskite materials have stimulated the interests of researchers to search for new perovskites and derivatives, possessing the properties of environment-friendly and good stability, as promising solar light harvester. In this work, we have mainly studied the geometric structures, electronic and optical properties of the three stable lead-free perovskite derivatives Rb〈sub〉2〈/sub〉SnX〈sub〉6〈/sub〉(X = Cl, Br and I) by employing the first principles method based on the Density Functional Theory. The consequences reveal that all the three compounds possess direct band gap. Thereinto, Rb〈sub〉2〈/sub〉SnX〈sub〉6〈/sub〉 exhibits superior photovoltaic performance in terms of high optical absorption coefficients compared with Cs〈sub〉2〈/sub〉SnI〈sub〉6〈/sub〉 and CH〈sub〉3〈/sub〉NH〈sub〉3〈/sub〉PbI〈sub〉3〈/sub〉, which reach over 10〈sup〉5〈/sup〉 cm〈sup〉−1〈/sup〉. Particularly, Rb〈sub〉2〈/sub〉SnI〈sub〉6〈/sub〉 exhibits an appropriate band gap of 1.1 eV and small effective mass. These results demonstrated that perovskite derivatives Rb〈sub〉2〈/sub〉SnX〈sub〉6〈/sub〉 may be potential candidate for excellent light absorbing material.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Dominic Davis, Maurizio Troiano, Alfonso Chinnici, Woei L. Saw, Timothy Lau, Roberto Solimene, Piero Salatino, Graham J. Nathan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We present the first experimental assessment of the influence of receiver tilt angle on the particle residence time distribution (RTD) of a two-phase solar particle receiver. The tracer pulse response method is used to measure the particle RTD within a laboratory-scale vortex-based solar particle receiver, with the particle phase itself used as the tracer. The experimental parameters of particle size, transporting gas inlet velocity and a range of receiver tilt angles – spanning 180° from vertically upward to downward facing – were systematically varied to determine the influence of key controlling parameters on the particle RTD within the receiver. It was found that the Stokes number of the two-phase flow evaluated at the receiver outlet, 〈em〉Sk〈sub〉out〈/sub〉〈/em〉, has a controlling influence on the residence time and that the influence of the receiver tilt angle is significant for large particles (〈em〉Sk〈sub〉out〈/sub〉〈/em〉 〉 10) but weak for small particles (〈em〉Sk〈sub〉out〈/sub〉〈/em〉 ~ 1). This implies that it is preferable to operate tower-mounted systems (i.e. with downward facing receiver tilt angles) with 〈em〉Sk〈sub〉out〈/sub〉〈/em〉 ~ 1. Furthermore, a preliminary scale-up assessment suggests that the influence of tilt angle on the residence time of particles 200 µm and smaller will be insignificant for a nominal 50 MW-scale receiver, which will provide flexibility in the design of industrial-scale devices. Finally, the residence time behaviour for the range of tilt angles assessed can be well described by an analytical compartment model consisting of a small plug flow reactor, followed by two continuously-stirred tank reactors in parallel with a second plug flow reactor.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Walid El Huni, Soufiane Karrakchou, Yacine Halfaya, Muhammad Arif, Matthew B. Jordan, Renaud Puybaret, Taha Ayari, Houda Ennakrachi, Chris Bishop, Simon Gautier, Ali Ahaitouf, Paul L. Voss, Jean Paul Salvestrini, Abdallah Ougazzaden〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉InGaN nano-structures, grown using nano selective area growth, have been shown to exhibit high crystalline quality, even for high In content InGaN alloy, and reduced polarization charge effect. They are thus very attractive for the realization of high efficiency solar cells. Compared to planar InGaN absorbers, nanopyramid-based absorbers are shown to relax the usual challenging constraint on the doping of the p-GaN layer, which would be needed to overcome the polarization-induced electric field. NP-based solar cells maintain the same performance with ten times lower p-GaN doping. Furthermore, the SiO〈sub〉2〈/sub〉 mask used for selective area growth of the nanopyramids is shown to help trap light into the nanopyramids, leading to increased optical absorption and thus efficiency. Last, InGaN nanopyramid absorber-based solar cells can allow for a higher InGaN residual donor concentration than that of the planar InGaN solar cells. Overall, an optimized In〈sub〉0.3〈/sub〉Ga〈sub〉0.7〈/sub〉N nanopyramid-based solar cell can lead to an efficiency twice than that of a planar InGaN-based solar cells with standard p- and n-GaN doping level. As a proof of concept, an In〈sub〉0.09〈/sub〉Ga〈sub〉0.91〈/sub〉N nanopyramid-based solar cell has been fabricated and is shown to have larger short circuit photocurrent and open circuit voltage than a state of the art In〈sub〉0.08〈/sub〉Ga〈sub〉0.92〈/sub〉N-based planar solar cell.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): D. Kishore Kumar, Srinivasa R. Popuri, Sanjay Kumar Swami, Obinna R. Onuoha, Jan-Willem G. Bos, Baixin Chen, Nick Bennett, H.M. Upadhyaya〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, the scalable screen printing process has been adopted to prepare low-cost and earth-abundant tin selenide (SnSe) films to study as the counter electrode in dye-sensitized solar cells (DSSCs). The SnSe powder was synthesized by solid state reaction method and corresponding films were fabricated by screen printing technique. The electrocatalytic activity of SnSe for redox iodide/triiodide (I〈sup〉−〈/sup〉/I〈sub〉3〈/sub〉〈sup〉−〈/sup〉) couple and charge transfer resistance at the CE/electrolyte interface were characterized by cyclic voltammetry and electrochemical impedance spectroscopy. The DSSC with SnSe counter electrode exhibited with power conversion efficiency (PCE) of ~5.76% with open-circuit voltage of 0.63 V and short circuit current density of 12.39 mA/cm〈sup〉2〈/sup〉 whereas the DSSC with platinum counter electrode showed PCE of 8.09% with open-circuit voltage of 0.68 V and short circuit current density of 14.77 mA/cm〈sup〉2〈/sup〉. Thus, earth abundant and low cost SnSe films fabricated by screen printing technique could be an alternative to costly platinum counter electrode in DSSC.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0038092X19307388-ga1.jpg" width="175" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Ricardo Salazar, Juan Gallardo-Arriaza, Jorge Vidal, Camilo Rivera-Vera, Carla Toledo-Neira, Miguel A. Sandoval, Lorena Cornejo-Ponce, Abdoulaye Thiam〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉This work addresses the removal of Acid Blue 29 (AB29) textile dye by a solar photo-electro-Fenton (SPEF) process. Ten liter AB29 solutions containing 100 mg L〈sup〉−1〈/sup〉 total organic carbon (TOC), 0.5 mM Fe〈sup〉2+〈/sup〉 and 0.05 M Na〈sub〉2〈/sub〉SO〈sub〉4〈/sub〉 at a pH of 3.0 were electrolyzed by applying current densities of 25 and 50 mA cm〈sup〉−2〈/sup〉 in a pilot plant built in our laboratory. The pilot plant was composed of an electrochemical filter press cell with a dimensionally stable anode (DSA-type) and an air-diffusion cathode coupled to a solar photo-reactor.〈/p〉 〈p〉AB29 was completely mineralized by SPEF at the end of electrolysis, while the solution achieved decolorization in short periods of time on sunny days. Reaction intermediates, such as aromatic compounds, carboxylic acids and inorganic ions, were found during the oxidation process. Solar irradiation favors the mineralization of the dye in cost and efficiency compared to other electrochemical methods. Moreover, the treatment of an industrial textile effluent containing AB29 by SPEF produced mineralization greater than 90% on sunny days.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Kamran Ali Khan Niazi, Wajahat Akhtar, Hassan A. Khan, Yongheng Yang, Shahrukh Athar〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Monitoring and maintenance of photovoltaic (PV) modules are critical for 〈del〉a〈/del〉 reliable and efficient operation. Hotspots in PV modules due to various defects and operational conditions may challenge the reliability, and in turn, the entire PV system. From the monitoring standpoint, hotspots should be detected and categorized for subsequent maintenance. In this paper, hotspots are detected, evaluated, and categorized uniquely by using a machine learning technique on thermal images of PV modules. To achieve so, the texture and histogram of gradient (HOG) features of thermal images of PV modules are used for classification. The categorized hotspots are detected by training the machine learning algorithm, i.e., a Naive Bayes (〈em〉n〈/em〉Bayes) classifier. Experimental results are performed on a 42.24-kWp PV system, which demonstrates that a mean recognition rate of around 94.1% is achieved for the set of 375 samples.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Raquel Simón-Allué, Isabel Guedea, Raúl Villén, Gonzalo Brun〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉In this work we evaluate the experimental behaviour of several photovoltaic-thermal panels (PVT) and its energy performance after adding a layer of phase change material (PCM) inside the panel. In order to assess the energy dependency with the heat absorber, different materials and geometries have been considered, whose results were compared to a traditional sheet-and-tube copper absorber. Glazed and unglazed configurations were also explored in each model.〈/p〉 〈p〉PVT panels were exposed to exposed to the sun during the hours of maximum irradiance and subjected to different working conditions to properly evaluate their thermal performance. Results showed a slightly variation in the electrical generation but a great difference in the thermal performance between glazed and unglazed configuration. Regarding the heat absorber, higher thermal performance was found in the aluminum configuration rather than the polymeric case, but similar production with regard to the electrical generation. Attending to the PCM, results did not show a significant thermal improvement but a better distribution of the heat production, reaching to generate up to 30% of maximum thermal power after removing sun exposure.〈/p〉 〈p〉Although further works are needed to analyze the long-term effect of the PCM on photovoltaic-thermal units, this study provides experimental information of the PCM and its real performance when working with different heat absorber units.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 189〈/p〉 〈p〉Author(s): Hamid Heidarzadeh〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The main purpose of this work is to investigate the efficiency dependence of a thin silicon solar cell on non-uniformity in size of the rectangle back gratings. Here, efficiency enhancement is done using a rectangular back grating with a Gaussian random distribution. The grating is one of the main optical trapping strategies. A rectangle grating is placed at the rear as a mirror that reflects and scatters light into absorber to increase the light traveling length inside the active region. DBR and horizontal grating is used in the rear side and we focus on non-uniformity of rectangle grating sizes to govern the light inside the cell. The results show using this structure, we can manage the absorption spectra and the photocurrent significantly is increased. The efficiency of a 3 µm Si-type solar cell is increased near to 20%. In addition, when the angle of incidence is considered between 5–20°, the efficiency of the proposed structure is higher than the normal incidence. It is believed that the obtained results are helpful in the design of a thin film silicon solar cell.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 189〈/p〉 〈p〉Author(s): Weitao Shao, Yueqiu Liu, Ke Li, Siyu Zhao, Guang Shao, Jing-Kun Fang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Small molecule organic dyes (SMODs) 〈strong〉FWD7〈/strong〉 and 〈strong〉FWD8〈/strong〉 featuring novel donor bis(arylvinyl)phenyl amino (BAPA) were designed for dye-sensitized solar cells (DSSCs). Absorption spectra of 〈strong〉FWD7〈/strong〉 featuring furanyl groups and 〈strong〉FWD8〈/strong〉 featuring thiophenyl groups showed about 20 nm bathochromic shifts and obviously bigger molar extinction coefficients (〈em〉ε〈/em〉) compared with 〈strong〉FWD5〈/strong〉 featuring phenyl groups. The DSSCs sensitized by 〈strong〉FWD7〈/strong〉 and 〈strong〉FWD8〈/strong〉 exhibited good photovoltaic parameters: short-circuit current density (〈em〉J〈/em〉〈sub〉sc〈/sub〉) 9.88 and 11.59 mA cm〈sup〉−2〈/sup〉, open-circuit voltage (〈em〉V〈/em〉〈sub〉oc〈/sub〉) 0.69 and 0.75 V, and power conversion efficiency (〈em〉η〈/em〉) 4.89% and 6.01%, respectively. The bigger R〈sub〉rec〈/sub〉 and 〈em〉τ〈/em〉〈sub〉e〈/sub〉 values of 〈strong〉FWD8〈/strong〉 (R〈sub〉rec〈/sub〉 = 88.53 Ω cm〈sup〉−2〈/sup〉 and 〈em〉τ〈/em〉〈sub〉e〈/sub〉 = 10.76 ms) compared with 〈strong〉FWD7〈/strong〉 (R〈sub〉rec〈/sub〉 = 59.06 Ω cm〈sup〉−2〈/sup〉 and 〈em〉τ〈/em〉〈sub〉e〈/sub〉 = 6.80 ms) gave a good explanation of the former’s bigger 〈em〉V〈/em〉〈sub〉oc〈/sub〉. The results showed that both bis(furanylvinyl)phenyl amino and bis(thiophenylvinyl)phenyl amino groups are good donor groups, while the latter is more efficient.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 189〈/p〉 〈p〉Author(s): Mohamed Alhaj, Sami G. Al-Ghamdi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Concentrated solar power (CSP) technology has the potential to reduce the environmental impacts of thermal desalination processes and supply freshwater in remote areas, but it still has not been demonstrated in a commercial project. This problem raises concerns about the long-term reliability and economic feasibility of this technology, particularly when implemented at a large scale, which is the niche market for desalination. In this study, we obtained further insights into the economics of concentrated solar thermal desalination based on a representative calculation of the levelized cost of water (LCOW) and a cost sensitivity analysis. In addition, we compared our cost estimations with those of previous studies and evaluated the reasons for their significant variation. Moreover, we discuss market commercialization barriers from a policy perspective. We found that the LCOW for solar-driven thermal desalination ranges from $0.94–4.31 per m〈sup〉3〈/sup〉 of freshwater, where the cost is affected mainly by the capital expenditure on the solar field and the operating expenditure of the desalination plant. Little empirical evidence from previous studies supports the economies of scale argument for concentrated solar thermal desalination. Several policies are suggested to improve the competitiveness of large-scale concentrated solar thermal desalination.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 189〈/p〉 〈p〉Author(s): M. Saadat, O. Amiri, A. Rahdar〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The conventional CdS layer in Cu(In〈sub〉1−x〈/sub〉,Ga〈sub〉x〈/sub〉)Se〈sub〉2〈/sub〉 based solar cells replaced by (Zn〈sub〉1−y〈/sub〉,Sn〈sub〉y〈/sub〉)O as a buffer layer and the solar performance analyzed. An initial model based on an experimental device has been established. The dependence of solar cells performance on the change of Ga concentrations in CIGS absorber and Sn concentrations ZnSnO (band gap of ZnSnO) buffer layer was investigated. The optimum values of Ga and Sn concentrations were found at x = 1 and y = 0.2, leading to a conversion efficiency of 25.36%.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0038092X19307649-ga1.jpg" width="349" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 189〈/p〉 〈p〉Author(s): Ubaid Khan, Yu Zhinong, Abbas Ahmad Khan, Almas Zulfiqar, Qudrat Ullah khan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Photovoltaic research has recently attracted great attention. Photovoltaic energy with the solution of methylimine incorporating with lead halide perovskite absorbent has reached the efficiency of almost 21% in configurations of solid state devices, which has replaced traditional dye-sensitized solar cells and evaporated organic solar cells as well as several thin-film photovoltaic films. Due to development in photovoltaic devices and its promising results, interest in this research has been increased. Consequently, it is essential to explain the operational mechanism of solar cells based on perovskite for further development. In this article, we present the structure and the method preparation of methylamine lead halide of organic-inorganic hybrid perovskite and review its current research on the application of solar cells. Meanwhile, the comparative analysis has been made between different points of view and key issues such as the choice of materials, the architecture of the device etc.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 189〈/p〉 〈p〉Author(s): Craig H. Swartz, Sadia R. Rab, Sanjoy Paul, Maikel F.A.M. van Hest, Benjia Dou, Joseph M. Luther, Gregory F. Pach, Corey R. Grice, Dengbing Li, Sandip S. Bista, Elizabeth G. LeBlanc, Matthew O. Reese, Mark W. Holtz, Thomas H. Myers, Yanfa Yan, Jian V. Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Band offsets at the back contact and front window layer in CdTe-based solar cells affect photovoltaic performance and challenge standard characterization methods. By analyzing the temperature and excitation dependence of both open circuit voltage and absolute photoluminescence intensity, we show that the effects band offsets can be separated from the effects of recombination and shunting. Solar cells were grown with MgZnO window layers and compared to cells with CdS window layers containing varying amounts of oxygen. It was demonstrated that band alignment rather than reduced recombination velocity is the reason for the success of MgZnO as a front interface contact. An assortment of thin back contact interlayers were also deposited, and a PbTe interlayer showed some promise as an Ohmic contact to the CdTe, though it appears to induce a photoconductive shunt. Finally, we show that the shunting resistance given by a standard current-voltage curve technique generally does not represent a physically meaningful quantity unless it is well below one kiloOhm square cm.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 189〈/p〉 〈p〉Author(s): Shuang Lu, Yinglin Wang, Chunxia Wu, Yichun Liu, Xintong Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Searching for large-scale, non-Pt, efficient counter electrode (CE) materials is still a key challenge to realize the applications of high-performance dye-sensitized solar cells (DSSCs). Herein, we report the spray fabrication of stable, uniform and efficient CoS counter electrode at temperature no higher than 100 °C from CoS nanoparticles prepared by the ultrasonic spray pyrolysis (USP) method. The as-fabricated USP-assisted CoS CEs exhibit comparable electrocatalytic activity to the traditional thermolyzed Pt CE, generating a power conversion efficiency of 8.6% for unoptimized DSSCs. This CoS CEs also exhibited prominent electrochemical and mechanical stability, uniform electrocatalytic activity at the size of 10 × 10 cm, and good bending durability when deposited on flexible ITO/PEN conductive substrates, manifesting the merits of this USP-based strategy for the development of high-performance non-Pt electrocatalysts.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 189〈/p〉 〈p〉Author(s): Esmaeil Sheibani, Mahsa Heydari, Hosein Ahangar, Hajar Mohammadi, Hossein Taherian Fard, Nima Taghavinia, Mahmoud Samadpour, Fariba Tajabadi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Carbazole compounds are p-type hole-transporting materials (HTMs) useful for perovskite solar cells (PSCs). In this work, we developed a new class of carbazol based HTMs; non-fused 3-D asymmetric structures (〈strong〉S14〈/strong〉 and 〈strong〉S12〈/strong〉) as HTM of PSCs. To the best of our knowledge, there is no report on non-fused HTMs with a high glass transition temperature (T〈sub〉g〈/sub〉 = 165 °C), which reduces crystallization and suppresses grain boundaries in glassy film, resulting in long-term durability. Experimental results show that tuning the carbazole moiety in 〈strong〉S14〈/strong〉 structure has a constructive influence on geometrical alignment, hole mobility, hydrophobicity, stability as well as efficiency. The resultant power conversion efficiency (PCE) of devices were 15.31% and 11.85% for 〈strong〉S14〈/strong〉 and 〈strong〉S12〈/strong〉, respectively. Cell efficiency decreases during the first day for all devices. But after this time, the cell efficiency of the device fabricated with 〈strong〉S14〈/strong〉 remains constant until 1000 h at atmospheric condition without encapsulation while for devices fabricated by 〈strong〉S12〈/strong〉 and Spiro-OMeTAD the cell efficiency decreases to 75% and 69%.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0038092X19307625-ga1.jpg" width="485" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 189〈/p〉 〈p〉Author(s): Yinglin Wang, Chao Ma, Chen Wang, Pengfei Cheng, Luping Xu, Li Lv, Hua Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The hierarchical double-hollow SnO〈sub〉2〈/sub〉@Air@TiO〈sub〉2〈/sub〉 microspheres (SATS) have been successfully synthesized by coating of SiO〈sub〉2〈/sub〉 and TiO〈sub〉2〈/sub〉 on the SnO〈sub〉2〈/sub〉 templates layer by layer, and its detailed performances for dye-sensitized solar cells (DSSCs) application also have been studied. SATS microspheres have an average diameter of about 600 nm while the sizes of SnO〈sub〉2〈/sub〉 hollow spheres are about 250 nm. The urchin-like SnO〈sub〉2〈/sub〉/TiO〈sub〉2〈/sub〉 composite microspheres with a large specific surface area of 96.1 m〈sup〉2〈/sup〉/g promote dye adsorption and efficient electron transport so as to increase short-circuit photocurrent density to 13.69 mA/cm〈sup〉2〈/sup〉. Compared to the traditional simple hollow structure, the double-hollow structure can ulteriorly improve light scattering ability. Hence, it reveals that the DSSC made from SATS nanospheres and P25 exhibits a higher photo conversion efficiency of 6.77%, a 33% improvement compared to the DSSC made from pure P25. The results indicate that the improved photovoltaic performance of SATS DSSCs can mainly attribute to the unique urchin-like double-hollow microstructure and the synergistic effect of SnO〈sub〉2〈/sub〉/TiO〈sub〉2〈/sub〉 composite material.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 189〈/p〉 〈p〉Author(s): Mojtaba Shivaie, Mohammad Mokhayeri, Mohammad Kiani-Moghaddam, Alireza Ashouri-Zadeh〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉During recent years, the optimal sizing of an autonomous hybrid energy system for microgrids operation management has been extensively explored. In this paper, with a new point of view, a reliability-constrained cost-effective model is developed to identify optimal sizing of an autonomous hybrid renewable system (AHRS). The significant aims of the proposed model are not only to address an exhaustive model for the AHRS by incorporating solar panel, wind turbine, diesel generator, and battery storage components, but also to implement practical considerations on the AHRS by considering its probabilistic characteristics. To do so, the proposed model takes into account total investment cost, the total fuel cost of the diesel generator, total maintenance cost and total expected load shedding cost in the optimization as four problem objectives subject to technical and operational constraints. A modified discrete bat search algorithm is widely employed to obtain the final optimal solution and followed by a Monte Carlo simulation method to handle non-deterministic characteristics pertaining to load demand, solar and wind generations. The obtained results of the proposed model are given and meticulously evaluated. These results show the feasibility and capabilities of the newly proposed model in the optimal sizing of an AHRS when compared with other approaches.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Elias M. Salilih, Yilma T. Birhane〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper proposes a method for the analysis and simulation of solar energy driven vapor compression refrigeration system with variable speed compressor under the real weather condition using the data sheets (of the PV panel and compressor) available from the manufacturers. The solar refrigeration system considered in this research study includes a non-tracking PV power source directly-coupled with a variable speed DC compressor. The operating point of the compressor of the considered solar refrigeration system is determined on the current versus voltage (I-V) plane, by intersecting the I-V curve of the PV panel with the I-V curve of the compressor. The operating speed of the compressor is determined to model the hourly variation of the performance of the refrigeration system. The analysis and simulation result show that the COP of the refrigeration cycle for the selected days is around 2.25 when the compressor runs at low speed, and the COP drops to its lowest value of 1.85 when the compressor operates at the highest speed. Furthermore, the simulation results indicated that an estimated radiation intensity 315 W/m〈sup〉2〈/sup〉 is required to be received on the tilted panel to run the considered compressor at its minimum rotational speed of 1800 rpm. To drive the compressor at its maximum rotational speed (4200 rpm), an estimated radiation intensity of 700 W/m〈sup〉2〈/sup〉 is required to fall on the PV panel. Finally, the proposed method can be used to estimate the performance of a directly coupled solar PV refrigeration system with variable speed compressor under specific weather condition.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Meysam Tayebi, Morteza Kolaei, Ahmad Tayyebi, Zohreh Masoumi, Zeynab Belbasi, Byeong-Kyu Lee〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, TiO〈sub〉2〈/sub〉 nanoparticles (NPs) /reduced graphene oxide (RGO) composites were prepared by hydrothermal process and physiochemical, optical, photocatalytic and photoelectrochemical properties of prepared materials was investigated. Photocatalytic activity measurement showed that methylene blue (MB) photodegraded faster by TiO〈sub〉2〈/sub〉-RGO composites compared to bare TiO〈sub〉2〈/sub〉. Furthermore, photoelectrochemical (PEC) properties of TiO〈sub〉2〈/sub〉 and TiO〈sub〉2〈/sub〉-RGO electrodes were investigated under the illumination of a 150 W Xe lamp in 1M aqueous solution of KOH as the electrolyte. Moreover, TiO〈sub〉2〈/sub〉-RGO electrodes showed greatly improved photocurrent density which is 3.3-fold higher than pure TiO〈sub〉2〈/sub〉. Combined analyses of Mott-Schottky plots and electrochemical impedance spectroscopy (EIS) confirmed that RGO in the TiO〈sub〉2〈/sub〉-RGO nanocomposite increased the donor concentration (N〈sub〉D〈/sub〉), decreased recombination process of charge carriers (τ〈sub〉D〈/sub〉), thinner the space charge layer (W〈sub〉SCL〈/sub〉) and reduced flat band potential (V〈sub〉Fb〈/sub〉) of the TiO〈sub〉2〈/sub〉, thereby greatly enhancing the PEC performances of the TiO〈sub〉2〈/sub〉 photoanodes. The improved PEC performance of the TiO〈sub〉2〈/sub〉-RGO nanocomposite compared to TiO〈sub〉2〈/sub〉 NPs attributed to great enhancement of electron transport through the RGO in the TiO〈sub〉2〈/sub〉- RGO film and consequently charge separation.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0038092X1930790X-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Saeed Mehran, Mohammad Nikian, Mehrangiz Ghazi, Hemad Zareiforoush, Iraj Bagheri〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉During drying process of paddy grains, as one of the major operations of rice milling process, a considerable amount of fossil fuel is consumed. The air pollutants emitted by combustion of fossil fuels are great threat to human health which strongly contribute to environmental problems. In the present study, to reduce the share of fossil fuels in drying process of paddy grains, a new type solar-assisted fluidized-bed dryer was used with the ability of thermal energy recovery. The drying system mainly consisted of a solar water heater, a solar-powered infrared lamp, a gas water heater, and a desiccant wheel. Two general conditions were considered for conducting the experiments: Natural gas drying (NGD), and Solar-assisted drying (SAD). The results of evaluations showed that the highest total energy consumption of the dryer was equal to 1.163 kWh which was obtained in NGD test mode, while the lowest amount of total energy consumption was obtained in SAD mode which was 0.314 kWh. The specific energy consumption of the drying system in SAD and NGD modes was in the range of 8.30–22.12 and 16.73–32.62 kWh/kg water evaporated, respectively. The highest value of solar fraction index was equal to 0.538 which was obtained at drying air temperature of 45 °C, drying air velocity of 8 m/s, while the lowest solar fraction value (0.179) was attributed to drying air temperature of 35 °C and air velocity of 7 m/s. Although applying the infrared lamp caused the solar energy fraction to increase to 0.741, however, the use of infrared lamp in the fluidizing chamber did not have a significant effect on the dehydration rate of the product. At two levels of the applied drying temperatures (35 °C and 45 °C), the required thermal energy during the drying process was completely supplied only by solar energy and without the need for fossil fuel.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): R. Jeyakumar, Atanu Bag, Reza Nekovei, R. Radhakrishnan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Perovskite solar cells gained importance in the recent years due to high power conversion efficiency and low-cost fabrication methods. Suitable solar cell properties can be obtained by fine tuning process parameters. Charge transport, optical band gap of perovskite absorber and energy band discontinuity on either side of absorber are an important factor in determining cell efficiency. In this work, theoretical studies on cell efficiency were performed as a function of absorber band gap since it determines band discontinuity. Band alignment investigation was performed to minimize band discontinuity between interfaces. Our results show that, valance band discontinuity at HTL/absorber interface (ΔE〈sub〉v1〈/sub〉) increases from 0.01 eV to 0.42 eV as the absorber band gap increases from 1.20 eV to 1.65 eV. On the other hand, valance band discontinuity at absorber/ETL interface (ΔE〈sub〉v2〈/sub〉) decreases from 2.07 eV to 1.62 eV. Conduction band discontinuity on both sides of absorber interface is almost constant and independent of absorber band gap. The increase in ΔE〈sub〉v1〈/sub〉 restricts holes collection which in turn affects cell efficiency. Depending upon ΔE〈sub〉v1〈/sub〉, cell efficiency increased from 24.96% to 29.40% and then decreased to 26.27%. This is due to the fact that maximum acceptable limit for ΔE〈sub〉v1〈/sub〉 is 0.20 eV and holes can reach back electrode when ΔE〈sub〉v1〈/sub〉 ≤ 0.20 eV. For the absorber band gap of 1.40 eV with ΔE〈sub〉v1〈/sub〉 of 0.17 eV, a high efficiency of 29.40% has been obtained with J〈sub〉sc〈/sub〉 of 28.70 mA/cm〈sup〉2〈/sup〉, V〈sub〉oc〈/sub〉 of 1.24 V, and FF of 82.60%.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0038092X19307650-ga1.jpg" width="292" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 190〈/p〉 〈p〉Author(s): Sebastijan Seme, Klemen Sredenšek, Bojan Štumberger, Miralem Hadžiselimović〈/p〉

Description: 〈p〉Publication date: 1 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 189〈/p〉 〈p〉Author(s): Ruwini D. Rajapaksha, Paul A. Fuierer, Mahinda I. Ranasinghe〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This research article is presenting photovoltaic performance of a sensitized solar cell with CuZnInS〈sub〉3〈/sub〉 as the sensitizer. The as-prepared nanocrystals were tested for the Cu:Zn composition dependent performance of photovoltaic solar cells. Out of all the tested nanocrystals with various compositions, a power conversion efficiency as high as 1.1% was observed with Cu:Zn 1:2 composition. A simple, low temperature method was employed to synthesize highly luminescent CuZnInS〈sub〉3〈/sub〉 quaternary nanocrystals using chloride salts of metal precursors. The synthesis was done by heating metal precursors followed by injection of elemental sulfur. The size and the elemental composition of the nanocrystals were investigated using transmission electron microscopy (TEM) and X-ray energy dispersive spectroscopy (EDS) The nanocrystals showed a uniform size distribution with average particle size of 5 nm with the exception of Cu:Zn 1:1 sample. The findings showed that the optical properties of these nanocrystals can be tuned by varying Cu:Zn metal precursor ratio. The as-synthesized nanocrystals showed photoluminescence quantum yield as high as 68%.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0038092X19307662-ga1.jpg" width="296" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy〈/p〉 〈p〉Author(s): Ayşe Ozdogan Dolcek, James M. Tinjum〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Within the heating, ventilation, and air conditioning (HVAC) sectors, ground coupled heat pumps (GCHPs) offer a potentially economical, low-carbon energy approach to lowering of the global energy budget. This study investigates the performance of a conventional vertical GCHP configuration with three boreholes (VERT), a conventional horizontal GCHP (HORZ), an unconventionally deep (300 m) single borehole GCHP (SING) system, and a conventional split natural gas air conditioning unit (NGAC). This study also compares potential for reduced greenhouse gas (GHG) emissions via the GCHP systems in Wisconsin, USA, using a comprehensive “cradle-to-grave” life-cycle analysis (LCA), which is implemented using SimaPro. Assuming the current Wisconsin electrical grid of 5.5% renewables, heating and cooling loads of a 186 m〈sup〉2〈/sup〉 residence, a coefficient of performance (COP) of 4 and a 25-year lifetime, an average of 272 metric ton CO〈sub〉2〈/sub〉 equivalent emissions is calculated for SING. Top contributors are heat-exchanger operation (93.3%), borehole drilling (2.4%), and circulation pump operation (1.5%). This amounts to GHG emissions savings of 10% and 19% over VERT and HORZ GCHPs, respectively, and 27% over NGAC. Sensitivity analyses determine that a grid with renewables penetration of 50% could save 68% GHG emissions over natural gas. As the use of fossil fuel decreases and the grid becomes cleaner, GCHP systems become even more beneficial from the perspective of lifetime GHG emissions. A COP of 5 could further reduce GHG emissions by 38%, indicating that the COP is a significant factor of GCHP environmental impacts.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 May 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 183〈/p〉 〈p〉Author(s): Rafael A. M. Ferreira, Daniel L.F. Pottie, Leonardo H. C. Dias, Braz J. Cardoso Filho, Matheus P. Porto〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Infrared Thermography (IRT) is a technique widely used to investigate thermal behavior of electrical components, and a representative number of papers is dedicated to applications of IRT in photovoltaics (PV). Despite this fact, few scientific publications discuss the challenges of measuring PV panels temperature outdoor, by means of IRT. From the back side, PV panels are opaque and diffuse surfaces, and IRT temperature measurement is straightforward, however, inspections are commonly made from the front side. From this latter perspective, PV panels are specular surfaces, highly directional-spectral dependent in the long wavelength infrared (LWIR) spectrum. Besides that, spectrum of incident LWIR thermal radiation, notably the sky and clouds, is discontinuous. Then, the conditions to assume PV surface gray are not sustained. To deal with this problem, we propose a post processing methodology. We use the full response of an IR camera, which is made considering that emissivity and transmissivity are equal to one, and consider the directional-spectral quantities to separate the target object signal from the other thermal radiation components. We applied the proposed methodology for outdoor PV panels in different sky conditions, resulting in a maximum absolute deviation of less then 3 °C, compared to a surface RTD.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 May 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 183〈/p〉 〈p〉Author(s): Lifeng Li, Bo Wang, Johannes Pottas, Wojciech Lipiński〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A three-dimensional compound parabolic concentrator (CPC) is designed for high-temperature solar thermochemical applications driven by radiation from a multi-source high-flux solar simulator. The basic geometrical parameters of the CPC including the acceptance angle and the entry aperture radius are determined using optical simulations. A cooling system for overheating protection is designed using engineering heat transfer correlations. A prototype CPC is manufactured using additive manufacturing and single point diamond turning techniques. The optical simulations show that the CPC increases the concentration ratio by a factor of 4.1 at an optical efficiency of 85.4%, reduces spillage loss from 78.9% to 32.1%, and reduces the flux non-uniformity on the target surface.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 May 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 184〈/p〉 〈p〉Author(s): Ahmad Modarresi Ghazvini, Javad Olamaei〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Hybrid energy systems such as PV-battery-diesel have been identified as an effective option to solve the power-supply problem and, therefore, the optimal sizing of such hybrid PV systems becomes important. Also, activities related to the demand side of the power system such as demand response programs are interested and, electric vehicle to grid (V2G) parking lot as a controllable load unit is recently used with demand response potential through charging and discharging V2Gs according to electricity price variations. The goal of this study is to develop and examine a heuristic optimization algorithm to solve the optimal sizing for hybrid PV-battery-diesel system with considerations for V2G parking lot as a controllable load. Simulation results show that utilization of V2G parking lot can reduce total cost for optimal sizing of hybrid PV-battery-diesel system by 5.21%.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 May 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 184〈/p〉 〈p〉Author(s): Fabrizio Ascione, Martina Borrelli, Rosa Francesca De Masi, Filippo de Rossi, Giuseppe Peter Vanoli〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Nowadays, the Nearly Zero Energy Buildings (NZEBs) represent the new target from 2019 onwards. The present study is focused on a single-family house (called BNZEB), placed in south Italy and specifically designed for a Mediterranean climate. The “Benevento” Nearly Zero Energy Building (that is why the name is “BNZEB”) is built with the purpose to be, at the same time, a research laboratory, suitable for testing and measuring energy demands, renewable energy conversion, indoor environmental quality and other aspects of performances in a realistic context.〈/p〉 〈p〉More in detail, firstly the BNZEB is presented and described; then, the early results of a monitoring campaign are shown with the purpose to characterise the energy performance of this building during the summer season and verify the effectiveness of chosen design solutions. For this reason, the daily energy balance is proposed with the aim to evidence the impact of solar production and electric storage on building energy consumptions. It is really important the presentation and the discussion about the monitoring results because, very often, the real performance does not coincide with the expected one and further optimizations are needed.〈/p〉 〈p〉Subsequently, a numerical model of the case study building, suitable for performing transient energy simulations, is used to compare the BNZEB building with other buildings: (a) one representative of the constructive standard established by Italian law; (b) a second one typical of the not-refurbished buildings stock of the city. The aim of this last part is to understand how much the BNZEB's energy performances are better compared to reference buildings during the summer season. Finally, the replicability of BNZEB design in Mediterranean cities, like Lisbon, Montpellier, Madrid, Seville and Athens is evaluated.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 May 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 184〈/p〉 〈p〉Author(s): Hamid-Reza Alizadeh, Hamid Mortezapour, Hamid-Reza Akhavan, Mohammad Balvardi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A closed-loop solar juice concentration system equipped with a liquid desiccant bed was investigated for barberry juice concentration and compared with the conventional evaporation processes. An unglazed flat plate solar collector was used for simultaneous regeneration of the desiccant solution. Experimental evaluation of the designed system was carried out at different flow rates of moving air as the circulating gas. The results showed that concentration time decreased from 480 to 360 min when the flow rate increased from 0.006 to 0.014 kg/s. Furthermore, raising the flow rate caused a decrease of 40% in effectiveness of dehumidification and an improvement of 33% in moisture evaporation rate. A minimum specific energy consumption of 3.33 MJ/kg was achieved at the air flow rate of 0.006 kg/s. The results indicated that all concentration methods significantly (p 〈 0.05) changed the color indices (〈em〉L*〈/em〉, 〈em〉a*〈/em〉, 〈em〉b*〈/em〉, hue angle, chroma and total color difference) of barberry juice. Although color quality of the concentrated juice by the rotary evaporator was better than the other methods, the solar juice concentration system at the lowest flow rate can be proposed for fruit juice processing industries with regard to energy consumption and acceptable and competitive color quality of the processed juices.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 23 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy〈/p〉 〈p〉Author(s): Merve Ozturk, Ibrahim Dincer, Nader Javani〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the current study, a combined system which consists of gas and steam turbines supported by concentrating solar receiver is studied through a thermodynamic approach using energy and exergy methods. Because of the intermittent nature of solar energy, a rock bed thermal energy storage system is incorporated into the system. The rock bed storage allows the secondary cycle to operate independently in order to generate electricity at night or once the solar energy is not available. Charging capacity of the rock bed is 9 MW for an 8 h period of time. The rock bed stores thermal energy for 4 h and thereafter, discharges it to run the steam cycle for 12 h. The energy and exergy efficiencies of the system are investigated through specific parametric studies to examine the effects of changing state properties and working conditions on energy and exergy efficiencies. According to the performance evaluation, the gas turbine could generate 3.87 MW〈sub〉e〈/sub〉 power while 1.76 MW〈sub〉e〈/sub〉 power is generated by the steam turbine. The overall energy and exergy efficiencies are obtained to be 69.2% and 37.3%, respectively.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 May 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 183〈/p〉 〈p〉Author(s): Reza Bakhshi–Jafarabadi, Javad Sadeh, Adel Soheili〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nowadays, grid–connected photovoltaic (GCPV) system is known as a top leading technology among all resources. However, it still suffers from drastic investment costs. Detailed economic studies should be conducted in this regard to make this technology as gainful as possible. A practical approach is the “optimum economic design”, trying to find an electrically possible layout, i.e. number of series modules and parallel strings as well as the inverter number with the highest profit. This problem is inherently an quadratic integer programming owing to the multiplication of two integer variables in its objective function and some technical constraints. This nonlinear problem should be solved by exhaustive search methods, including comparative and evolutionary algorithms (EAs) such as particle swarm optimization (PSO) and genetic algorithm (GA). In this paper, a new formulation based on the definition of new binary variables has been proposed to convert this problem to the binary linear programming (BLP). The provided method finds the global optimum solution in a scale of seconds while EAs have to be run numerous times in a scale of hours to reach a sufficiently good answer. Moreover, although current methodologies are rarely covered GCPV systems with multiple inverter types, this formulation can be easily developed for systems with several inverter types. The simulations of a 1.1 MW power plant system endorse that the output design provided by the proposed method assures 95,000 $ (1.94%) higher profit compared with those presented by GA. The sensitivity analysis, provided for the prototype system by the efficient new algorithm, also unveils it is economically viable for even 52% of the current feed–in tariff, 40% energy generation lower than the estimated value and 1.1 $/W price rise for the initial investment.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 May 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 183〈/p〉 〈p〉Author(s): Dimitrij Chudinzow, Jannik Haas, Gustavo Díaz-Ferrán, Simón Moreno-Leiva, Ludger Eltrop〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Bifacial photovoltaics (bifacial PV) offer higher energy yields as compared to monofacial PV. The development of appropriate models for simulating the energy yield of bifacial PV power plants is a major topic in both research and industry. In particular, the adequate calculation of the energy yield from ground-reflected irradiance (GRI) is challenging. The purpose of this work is to investigate the currently available energy yield models and suggest areas for improvement. A new model with the proposed enhancements is used to investigate the behaviour of bifacial PV power plants in more detail. The model calculates the absorbed irradiation originating from eight irradiance contributions for the front and rear of each cell string: DNI, DHI, GRI from DHI (GRI〈sub〉DHI〈/sub〉) and GRI from DNI (GRI〈sub〉DNI〈/sub〉). The model was tested using a defined case study power plant. The breakdown of absorbed irradiation (subscript “ab”) into its contributions revealed that while in summer months GRI〈sub〉DNI-ab-rear〈/sub〉 is significantly larger than GRI〈sub〉DHI-ab-rear〈/sub〉, both are roughly the same in winter months. Furthermore, for the calculation of GRI the common simplification of infinitely long module rows was avoided by implementing an algorithm for the view factor calculation for a three-dimensional space. This procedure allowed for the assessment of impact of the ground size on the annual energy yield. In a sensitivity analysis, it has been shown that the extension of the relevant ground area resulted in an asymptotical increase of the energy yield. Additionally, the impact of ground shadows on the power plant’s performance was quantified. The presence of ground shadows reduced the annual electricity generation by almost 4%, compared to a hypothetical scenario where no ground shadows existed. Finally, five different ground surfaces and the resulting bifacial gains were analysed. The results show that while dry asphalt (12% reflectivity) gave less than 6% of bifacial gain related to generated electricity (BG〈sub〉el〈/sub〉), the use of a white membrane (70%) would result in 29% of BG〈sub〉el〈/sub〉.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0038092X19302993-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 May 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 183〈/p〉 〈p〉Author(s): Prashant Upadhyay, Rajneesh Kumar〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This Paper proposes a high voltage gain dc-dc lift-up converter for photovoltaic based power generation especially used for microgrid applications. Proposed converter has two stage boosting with effective overall gain in form of quadratic-quadrupler boost (QQB) factor. The converter achieves high voltage gain with low duty ratio operation which is necessary for efficient operation of boost converter. Here, a lower value of winding turns ratio in coupled inductor was selected to reduce leakage inductance and voltage stress across switching devices. To analyze the converter operation, simulation was carried out using PSIM software and results were validated using experiments conducted on a 200 W hardware prototype developed in laboratory. A boost factor of 10.5 is achieved at a turn’s ratio of 1.9 and about 35% of duty cycle. Maximum efficiency of ∼92.9% is achieved for the proposed converter at 175 W output power operation for 40 V input voltage.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0038092X19303032-ga1.jpg" width="358" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 May 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 183〈/p〉 〈p〉Author(s): Zejie Fei, Yu Zhang, Min Ge, Yongtian Wang, Yanli Li, Jinhui Cheng, Baoren Wei, Huiqi Hou, Hongtao Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A time of flight mass spectrometer (TOF-MS) combined with a specially designed in-situ heating furnace was used for analyzing gaseous products evolved during salt decomposition. The thermal decomposition behavior of solar salt (60 wt% NaNO〈sub〉3〈/sub〉–40 wt% KNO〈sub〉3〈/sub〉) and sodium nitrite at temperature above melting point was investigated. According to mass spectra recorded at different temperature, both solar salt and sodium nitrite thermally decomposed above their melting point and the main products are NO and N〈sub〉2〈/sub〉 respectively. An unusual N〈sub〉2〈/sub〉O was also observed in gaseous products by TOF-MS, while no O〈sub〉2〈/sub〉 or NO〈sub〉2〈/sub〉 was found at temperature bellow 300 °C. The result shows a very different reaction process from the common sense that O〈sub〉2〈/sub〉 or NO〈sub〉2〈/sub〉 should exist in the decomposition process. Based on these new evidences, the thermal decomposition mechanism of molten nitrite/nitrates salt is proposed, which suggests that there should be intermediate state such as superoxide and peroxide ions in the molten salt in the initial thermal-chemical reaction process.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 176〈/p〉 〈p〉Author(s): Dazhi Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Solar forecasting using data collected by satellites or sensor networks is often framed as a many-predictor spatio-temporal regression problem. Whereas the regressand is the irradiance at the focal location, the regressors could be the irradiance at any neighboring location with any time lag. Lasso—the least absolute shrinkage and selection operator—is commonly used for regressor selection and regularization in order to enhance the forecast accuracy and interpretability of the regression model. However, when the number of regressors is much larger than the number of samples, lasso-type regressions are limited by the curse of dimensionality and the insufficient degree of freedom.〈/p〉 〈p〉The ultra-fast preselection algorithm herein proposed provides a remedy to the above-mentioned problem. The algorithm uses (probably) the world’s fastest similarity search routine, and preselects a user-defined number of most-relevant regressors based on the z-normalized Euclidean distance. The preselected regressors are then fed to lasso for forecasting. The algorithm is completely free from the curse of dimensionality, and does not require any meteorological prior, such as wind information or cloud vector field. It is customizable for other forecasting methods, such as vector autoregression or kriging, and can be implemented in just 10 lines of code.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 177〈/p〉 〈p〉Author(s): Andreas Fritsch, Cathy Frantz, Ralf Uhlig〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Solar thermal power plants with central receiver and thermal storage are expected to be one key technology in future electricity generation, because they are renewable and due to the thermal storage independent of the current solar radiation. State-of-the-art solar power plants often use molten nitrate salts as heat transfer fluid. The use of liquid sodium instead leads to lower electricity generation costs. Sodium has a high thermal conductivity and thus large heat transfer rates are possible. Hence, a smaller absorber surface is sufficient for the same thermal power. As a result, the sodium receiver achieves a higher efficiency at lower investment cost. Additionally, the aiming strategy, which reduces the peak heat flux on molten salt receivers isn’t necessary for sodium. Even at high heat flux densities, the absorber tubes will be cooled sufficiently due to the high heat transfer coefficients. Therefore, the sodium receiver in this analysis is designed for one single aim point, resulting in a heat flux density of 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si16.gif" overflow="scroll"〉〈mrow〉〈msub〉〈mrow〉〈mover accent="true"〉〈mrow〉〈mi〉q〈/mi〉〈/mrow〉〈mrow〉〈mo〉̇〈/mo〉〈/mrow〉〈/mover〉〈/mrow〉〈mrow〉〈mtext〉mean〈/mtext〉〈/mrow〉〈/msub〉〈mo〉=〈/mo〉〈mn〉1.06〈/mn〉〈mspace width="0.25em"〉〈/mspace〉〈mtext〉MW〈/mtext〉〈mo〉/〈/mo〉〈msup〉〈mrow〉〈mtext〉m〈/mtext〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msup〉〈/mrow〉〈/math〉 and 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si17.gif" overflow="scroll"〉〈mrow〉〈msub〉〈mrow〉〈mover accent="true"〉〈mrow〉〈mi〉q〈/mi〉〈/mrow〉〈mrow〉〈mo〉̇〈/mo〉〈/mrow〉〈/mover〉〈/mrow〉〈mrow〉〈mtext〉peak〈/mtext〉〈/mrow〉〈/msub〉〈mo〉=〈/mo〉〈mn〉2.99〈/mn〉〈mspace width="0.25em"〉〈/mspace〉〈mtext〉MW〈/mtext〉〈mo〉/〈/mo〉〈msup〉〈mrow〉〈mtext〉m〈/mtext〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msup〉〈/mrow〉〈/math〉. The state-of-the-art system with molten salt considers 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si18.gif" overflow="scroll"〉〈mrow〉〈msub〉〈mrow〉〈mover accent="true"〉〈mrow〉〈mi〉q〈/mi〉〈/mrow〉〈mrow〉〈mo〉̇〈/mo〉〈/mrow〉〈/mover〉〈/mrow〉〈mrow〉〈mtext〉mean〈/mtext〉〈/mrow〉〈/msub〉〈mo〉=〈/mo〉〈mn〉0.51〈/mn〉〈mspace width="0.25em"〉〈/mspace〉〈mtext〉MW〈/mtext〉〈mo〉/〈/mo〉〈msup〉〈mrow〉〈mtext〉m〈/mtext〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msup〉〈/mrow〉〈/math〉 and 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si19.gif" overflow="scroll"〉〈mrow〉〈msub〉〈mrow〉〈mover accent="true"〉〈mrow〉〈mi〉q〈/mi〉〈/mrow〉〈mrow〉〈mo〉̇〈/mo〉〈/mrow〉〈/mover〉〈/mrow〉〈mrow〉〈mtext〉peak〈/mtext〉〈/mrow〉〈/msub〉〈mo〉=〈/mo〉〈mn〉1.0〈/mn〉〈mspace width="0.25em"〉〈/mspace〉〈mtext〉MW〈/mtext〉〈mo〉/〈/mo〉〈msup〉〈mrow〉〈mtext〉m〈/mtext〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msup〉〈/mrow〉〈/math〉. The presented techno-economic analysis of two sodium based concepts compared to a reference system with molten salt results in up to 16% lower electricity generation costs.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 177〈/p〉 〈p〉Author(s): Elena Villar-Navarro, Irina Levchuk, Juan José Rueda-Márquez, Manuel Manzano〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Technologically advanced recirculation aquaculture systems (RAS), developed for intensive farming, allows to recycle about 90–99% of water. As a result, accumulation of pathogenic bacteria in water often occurs and possesses threat of infectious fish diseases. The goal of this study was to evaluate feasibility of solar disinfection in combination with hydrogen peroxide for seawater and real marine aquaculture effluent. Specific roles of solar disinfection (SODIS), hydrogen peroxide and highly reactive oxidizing species (experiments conducted in presence of tert-butyl alcohol), generated in combined SODIS/H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 process were investigated. Natural consortia of 〈em〉Vibrio〈/em〉 spp., known as highly resistant pathogen, present in seawater and real marine aquaculture effluent were chosen as target microorganisms. The SODIS/H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 process significantly enhances inactivation of natural 〈em〉Vibrio〈/em〉 consortia (〈em〉Vibrio harveyi, Vibrio owensii〈/em〉 and 〈em〉Vibrio alfacsensis〈/em〉) in seawater in comparison with individual SODIS and H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 treatment. The best results in terms of 〈em〉Vibrio〈/em〉 spp. inactivation efficiency was obtained with SODIS/H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 conducted using open channel raceway reactor. The efficiency of 〈em〉Vibrio〈/em〉 spp. inactivation by SODIS/H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 in raceway and compound parabolic collector (CPC) reactors was found to be similar, requiring the dose of 28–29 Wh m〈sup〉−2〈/sup〉 for complete inactivation of 〈em〉Vibrio〈/em〉 spp. present in seawater. Absence of toxic effect of residual H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 for 〈em〉Nannochloropsis gaditana,〈/em〉 as well as absence of 〈em〉Vibrio〈/em〉 spp. regrowth (48 h) indicate suitability of SODIS/H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 process for inactivation of pathogenic bacteria in aquaculture effluent and following nutrients removal by microalgae. Moreover, feasibility of SODIS/H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 performed in raceway reactor for disinfection of real aquaculture effluent, containing more than 5⋅10〈sup〉3〈/sup〉 CFU mL〈sup〉−1〈/sup〉 of 〈em〉Vibrio harveyi〈/em〉, was demonstrated requiring the dose of 34.4 Wh m〈sup〉−2〈/sup〉 for complete 〈em〉Vibrio〈/em〉 spp. inactivation. The annual operation and maintenance cost of aquaculture effluent disinfection using CPC and raceway reactors were evaluated.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0038092X18311186-ga1.jpg" width="337" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 177〈/p〉 〈p〉Author(s): Dominic Davis, Mehdi Jafarian, Alfonso Chinnici, Woei L. Saw, Graham J. Nathan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report a first-order assessment of a novel vortex-based solar particle receiver and the sensitivity of its thermal performance to a number of key operational parameters. This assessment is made with a one-dimensional numerical model developed here to adapt the zonal method to calculate heat and mass transport within the enclosure of the solar vortex receiver (SVR) and to incorporate radiative and convective heat transfer between the particle phase, the air phase and the receiver wall together with re-radiative and conductive loss from the receiver. This simplified one-dimensional model allows for the systematic assessment of first order trends of mass and energy balance within the SVR and is used here to advance understanding of the dominant mechanisms controlling its thermal performance. Sensitivity studies of the thermal performance of the SVR reveal that the receiver can be configured to operate as either an air-heater or a particle-heater, depending primarily on the particle mass loading. For the present SVR configuration, the critical value of mass loading, 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si4.gif" overflow="scroll"〉〈mrow〉〈msub〉〈mover accent="true"〉〈mi〉m〈/mi〉〈mo〉̇〈/mo〉〈/mover〉〈mi〉p〈/mi〉〈/msub〉〈/mrow〉〈/math〉/〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"〉〈mrow〉〈msub〉〈mover accent="true"〉〈mi〉m〈/mi〉〈mo〉̇〈/mo〉〈/mover〉〈mrow〉〈mi mathvariant="italic"〉air〈/mi〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉 ≈ 1 was found to define the boundary, above which the device acts as a particle heater, and below which it acts as an air heater. Furthermore, an assessment of the two-phase flow direction found that a counter-flow (relative to the incident concentrated solar radiation) tends to result in a higher efficiency than a co-flow direction. The first order trends of the sensitivity of thermal performance of the SVR to the particle and air mass flow rates, particle size and receiver length were also assessed, finding that the ratio of receiver thermal input to heat capacity of the two-phase flow has a controlling influence on the thermal efficiency of the SVR, particularly with the front entry configuration. Overall receiver thermal efficiencies of up to 88% were predicted for the SVR operating with high mass flow rates of both particles and air, but it is expected that the thermal efficiency of the device for all operating conditions assessed here would increase with an increase in receiver scale from the laboratory-scale device considered here.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0038092X18310880-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 178〈/p〉 〈p〉Author(s): Ranbir Singh, Vivek Kumar Shukla〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Herein we report a 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′] dithiophene (ITIC) small molecule additive based bulk heterojunction (BHJ) perovskite solar cell (PSC). The BHJ PSC with 0.2 wt% of ITIC exhibits a power conversion efficiency (PCE) of 17.6% with remarkably enhanced short-circuit current of 23.7 mA cm〈sup〉−2〈/sup〉 as compared to reference PSC (without ITIC). The addition of ITIC plays an important role in improving the quality of the perovskite film like enhanced absorption, compact grains with reduced roughness (≈12.3 nm), higher electron mobility (μ〈sub〉e〈/sub〉 = 1.43 × 10〈sup〉-3〈/sup〉 cm〈sup〉2〈/sup〉 V〈sup〉-1〈/sup〉 s〈sup〉−1〈/sup〉), better charge extraction and thermal stability of the solar cells. The BHJ PSC device degraded only by ≈18% after 53 days at 80 °C in atmospheric condition. In addition, several important characteristics of solar cell like current-voltage hysteresis, charge transfer, and recombination losses have been studied.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0038092X18311885-ga1.jpg" width="489" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 178〈/p〉 〈p〉Author(s): Pawan Kumar Pathak, Anil Kumar Yadav〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In a solar photovoltaic (SPV) based hybrid renewable energy system, batteries are used as a power reservoir. SPV system provides energy under steady operating condition whereas SPV along with batteries serve as the source of energy under transient operating condition. This paper puts forward the design of a battery charging circuit through an intelligent fuzzy logic based discrete proportional-integral-derivative (FL-DPID) maximum power point tracking (MPPT) algorithm. SPV system in conjunction with FL-DPID MPPT technique driven DC-DC boost converter enhances the output voltage besides tracking maximum power point (MPP) under varying irradiance in between 400–1000 W/m〈sup〉2〈/sup〉 and a constant temperature of 25 °C. The output voltage of the boost converter drives the optimal PID (O-PID) controlled buck converter to behave as a battery charging circuit under non-deterministic atmospheric conditions. The objective of this study is to operate the designed SPV system at MPP under varying environmental condition in order to achieve higher efficacy, minimize overall system cost and obtain apropos voltage and current for effective charging of battery thereby reducing battery losses and enhancing life cycle. A 200 W prototype of an SPV panel has been designed, simulated and investigated in the MATLAB/Simulink environment.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0038092X18311939-ga1.jpg" width="344" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 177〈/p〉 〈p〉Author(s): Rui Su, Saba Ashraf, Ahmed El-Shafei〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Six novel heteroleptic amphiphilic polypyridyl Ruthenium (II) complexes, coded 〈strong〉FS01〈/strong〉-〈strong〉FS06〈/strong〉, with hetero-aromatic electron-donor ancillary ligands containing julolidine-derived moieties were synthesized to investigate the relationship between structure modulations of electron donors of Ru(II) dyes and their photophysical, electrochemical and photovoltaic properties for dye-sensitized solar cells (DSSCs). These modulations include: Ru(II) complexes with double “tails” (i.e. tetramethyl groups attached to the end of julolidine-based antennas, 〈strong〉FS04〈/strong〉) compared to the ones without double “tails” (〈strong〉FS01〈/strong〉); complexes with double small “flaps” (i.e. small acyclic electron donor auxochromes 〈em〉ortho〈/em〉 to the CH = CH bridge of stilbazole, 〈strong〉FS02〈/strong〉, 〈strong〉FS05〈/strong〉) compared to the ones with double large “flaps” (〈strong〉FS03〈/strong〉, 〈strong〉FS06〈/strong〉). Their low energy metal-to-ligand charge transfers (MLCT) band and molar absorptivities were all better than those of the benchmark, 〈strong〉N719〈/strong〉. It was also shown that the incorporation of double “flaps” into the ancillary ligands caused a slight red shift of light absorption. The photovoltaic properties were evaluated under 1.5 AM standard illumination condition and compared to 〈strong〉N719〈/strong〉. The highest photocurrent density (〈em〉J〈sub〉SC〈/sub〉〈/em〉) was observed for the complex with double “tails” and double small “flaps” (〈strong〉FS05〈/strong〉). The overall conversion efficiency for devices employing julolidine-derived Ru (II) complexes was in the following order 〈strong〉FS05〈/strong〉 〉 〈strong〉FS02〈/strong〉 〉 〈strong〉FS04〈/strong〉 〉 〈strong〉FS01〈/strong〉 〉 〈strong〉FS06〈/strong〉 〉 〈strong〉FS03〈/strong〉. 〈strong〉FS05〈/strong〉 (8.16%) outperformed the benchmark 〈strong〉N719〈/strong〉 (7.75%) in the photovoltaic performance, which is due to its best light-harvesting ability, highest molar extinction coefficient and smallest energy band gap among all the six dyes. To probe the interrelationship among julolidine-based electron donors of ancillary ligands, photocurrent and photovoltage of these dyes, the equilibrium molecular geometries of the ancillary ligands were calculated using DFT. The equilibrium molecular geometries of these dyes the photocurrent and photovoltage are dependent on the donating effect of alkyloxy auxochromes, the steric effect generated from the auxochromes and julolidine moieties, and the orientation of longer alkyloxy group. The introduction of double “tails” resulted in less dye aggregation and higher charge recombination resistance, leading to higher photocurrents and photovoltages in the solar cell performances. Despite of the donating effect of alkyloxy groups, the bulky double “flaps” mainly jammed the hole transportation between the redox couple of the electrolyte and the HOMO of thiocyanate groups (−NCS), translating into the decrease of photocurrent.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0038092X18311381-ga1.jpg" width="392" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 177〈/p〉 〈p〉Author(s): Maïna André, Richard Perez, Ted Soubdhan, James Schlemmer, Rudy Calif, Stéphanie Monjoly〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper examines two spatio-temporal approaches for short-term forecasting of global horizontal irradiance using gridded satellite-derived irradiances as experimental support. The first approach is a spatio-temporal vector autoregressive (STVAR) model combined with a statistical process for optimum selection of input variables. The second is an existing operational cloud motion vector (CMV) model. An evaluation of the predictive performance of these models is presented for a case study area in the Caribbean Islands. This region is characterized by a large diversity of microclimates and land/sea contrasts, creating a challenging solar forecasting context. Using scaled persistence as a reference, we benchmark the performance of the two spatio-temporal models over an extended 220 × 220 km domain, and for three specific, climatically distinct locations within this domain. We also assess the influence of intra-day solar resource variability on model performance. Finally, we present preliminary evidence that a blend of CMV and STVAR forecasts leads to improved accuracy under all conditions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 178〈/p〉 〈p〉Author(s): A.H. Mosaffa, Z. Ghaffarpour, L. Garousi Farshi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper deals with a novel solar-biogas fueled combined heat and power system with methanol and hydrogen production. The proposed energy system consists following subsystems: solar based biogas-steam reformer, gas turbine cycle, Rankine and organic Rankine cycles, pressure swing adsorption, carbon capture and sequestration and methanol synthesis unit. The selected solar system is molten salt tower-based concentrated solar thermal plant that provides required thermal energy for reforming process. The multigeneration system is comprehensive analyzed thermoeconomically and exergoenvironmentally. A parametric study is conducted to find the effects of key parameters on the system performance. The considered key parameters include steam to carbon ratio of reforming process, operating temperature and pressure of reformer. The results show that 〈em〉T〈/em〉〈sub〉r〈/sub〉 is the most effective parameters for improving system performance. A 200 K increase in reforming temperature, from 923 K to 1123 K, leads to decreases of 15% and 10% in the energy and exergy efficiencies, respectively. The opposite trend is observed for net power output and mass flow rate of produced methanol when key parameters change. Nevertheless, mass flow rate of produced methanol plays most important role for evaluating energy and exergy efficiencies. Also, gas turbine cycle and reformer have highest exergy destruction rate of 140 MW and 134 MW, respectively when system operates in optimum condition. Moreover, best exergoenvironmental parameters are obtained at higher value of reforming temperature and lower values of reforming pressure and steam to carbon ratio of reforming process.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 177〈/p〉 〈p〉Author(s): Flavia C.S.M. Padoan, Pietro Altimari, Francesca Pagnanelli〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The application of photovoltaics has been rapidly increasing over the past two decades driven by the idea that it could provide a fundamental contribution to the transition from traditional fossil fuels to renewable energy based economies. However, long-term sustainability of photovoltaics will be largely dependent on the effectiveness of the process solutions that will be adopted to recycle the unprecedented volume of end-of-life panels expected to be generated in the near future. Recycling is indispensible to avoid the loss of the valuable materials employed to produce the photovoltaic panels and, at the same time, prevent that harmful elements, including, for example, heavy metals, could be dispersed into the environment through improper disposal practices. In this article, the process solutions proposed over the past two decades to recycle photovoltaic panels are critically reviewed. Main objective is to provide the basis for the identification of the recycling solutions that can effectively sustain the continuous increase of the photovoltaic market. In order to assess the requirements that should be satisfied by the recycling processes, the legislation currently in force to regulate the management of end-of-life photovoltaic panels is reviewed, and the evolution of the PV market over the past two decades is analysed. Based on this analysis, forecasts are derived for the flux of end-of-life panels that will be generated over the coming four decades. A technical survey of the previously proposed recycling processes is successively performed by including, in addition to the analysis of the research studies published in scientific articles, a detailed review of the patented recycling processes. Indications are given to which may be the most promising processes in terms of their economic sustainability and environmental impact.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 177〈/p〉 〈p〉Author(s): A. Laref, M. Al-Enazi, H.R. Al-Qahtani, S. Laref, Xiaozhi Wu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Hybrid halide perovskite CH〈sub〉3〈/sub〉NH〈sub〉3〈/sub〉PbI〈sub〉3〈/sub〉 is emerging as a promising solar cell material owing to its low-cost fabrication and remarkable optical and electronic properties. In this scrutiny, we examined the structural stability, electronic structures, and optical properties of a pure cubic MAPbI〈sub〉3〈/sub〉 compound and the CH〈sub〉3−x〈/sub〉F〈sub〉x〈/sub〉NH〈sub〉3〈/sub〉PbI〈sub〉3〈/sub〉 (x = 0, 1, 2, 3) compounds derived by the substitutional impact of fluorine on the methylammonium (MA) organic cation. In our calculations, we employed the full-potential linear augmented plane wave (FP-LAPW) methodology within the generalized gradient approximation (GGA). From the minimization of total energy, the lattice parameter and formation energy of CH〈sub〉3−x〈/sub〉F〈sub〉x〈/sub〉NH〈sub〉3〈/sub〉PbI〈sub〉3〈/sub〉 (x = 0, 1, 2, 3) hybrid perovskites are computed. The results clearly revealed that the pure MAPbI〈sub〉3〈/sub〉 is the most stable perovskite among other structures. The electronic properties determined from the electronic density of states depend quite significantly on the impact of fluorine of MA organic cation and inorganic component, i.e. [PbI〈sub〉6〈/sub〉]〈sup〉−4〈/sup〉. The important optical spectra (the complex dielectric function, complex refractive index, absorption coefficient, energy loss function, and reflectivity) are computed for the halide perovskites (CH〈sub〉3−x〈/sub〉F〈sub〉x〈/sub〉NH〈sub〉3〈/sub〉PbI〈sub〉3〈/sub〉, x = 0, 1, 2, 3) versus the photon energy. The values of the static dielectric constants and the static refractive index are found to diminish with the increasing of the number of fluorine atoms in MA cation. The electronic polarizability was also calculated for all the considered materials in the high frequency optical span. Interestingly, the high absorption coefficient (∼10〈sup〉6〈/sup〉 cm〈sup〉−1〈/sup〉) and a band gap of around 1.6 eV render these hybrid perovskite materials to be prosperous for photovoltaic applications. For the various physical properties of pure CH〈sub〉3〈/sub〉NH〈sub〉3〈/sub〉PbI〈sub〉3〈/sub〉 compound, a good consistency is found comparatively to the available experimental and theoretical results. Our findings are expected to be of great interest for future investigations.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 176〈/p〉 〈p〉Author(s): D. López del Moral, A. Barrado, M. Sanz, A. Lázaro, P. Zumel〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉The mismatching phenomenon is one of the main issues in photovoltaic (PV) applications. It could reduce the generated power of a string when a PV panel has different performances from the other PV panels connected to the same string. Distributed Maximum Power Point Tracking (DMPPT) architectures are one of the most promising solutions to overcome the drawbacks associated with mismatching phenomena in PV applications. In this kind of architectures, a DC-DC module integrated converter (MIC) manages each PV panel, isolating it from the rest of the PV panels, for harvesting the maximum available power from the Sun. Due to the high number of DC-DC converters used in a grid-tied PV installation, the most desired MIC requirements are high efficiency, low cost and the capability of voltage step-up and step-down.〈/p〉 〈p〉This paper proposes the Buck-Boost Modified Forward (BBMSF) converter as a good candidate to be applied in DMPPT architectures. A complete analysis of the BBMSF converter is carried out, including the steady-state analysis as well as the small signal analysis in continuous conduction mode.〈/p〉 〈p〉The main advantages of the BBMSF converter are its step-up and step-down voltage transfer function; a higher simplicity, since it only includes a single controlled switch; the soft switching characteristics in all the diodes and MOSFET, reaching in some cases ZVS and ZCS, and yielding high efficiencies; the use of an autotransformer, with better performances than a typical Forward transformer; and the good dynamic performance, like the Forward converter ones.〈/p〉 〈p〉The theoretical analyses are validated through the experimental results in a 225 W BBMSF prototype designed and built under the requirements of a 100 kW grid-tied PV installation, achieving an efficiency up to 93.6%.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 177〈/p〉 〈p〉Author(s): Qiongfen Yu, Huirong Zhao, Hong Zhao, Shengnan Sun, Xu Ji, Ming Li, Yunfeng Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Tobacco-stem activated carbons (TACs) were prepared by ZnCl〈sub〉2〈/sub〉 activation and used for water vapor adsorption in solar drying system. The effects of activation temperature, activation time, and ZnCl〈sub〉2〈/sub〉 impregnation ratio on water vapor adsorption performance and BET specific surface area of TACs were carried out and the preparation conditions were analyzed by surface response methodology. Pore structure and morphology of the samples were characterized by N〈sub〉2〈/sub〉 adsorption-desorption isotherm and scanning electron microscope. Water vapor adsorption and desorption isotherms of TACs were carried out. A six subsequent adsorption-regeneration cycle of water vapor was investigated. The result shows that BET specific surface area of 1893.6 m〈sup〉2〈/sup〉/g, water vapor adsorption capacity of 563.4 mg/g are obtained in the optimum preparation conditions of activation temperature 621 °C, activation time 73 min and ZnCl〈sub〉2〈/sub〉 impregnation ratio of 1.70. Pore structure and surface area analysis shows that TAC21 is prepared as a microporous activated carbon and suitable for water vapor adsorption application. Both TAC18 and TAC21 possess an excellent reversibility of water vapor adsorption under the tested condition. The result confirms that the TAC adsorbents would be the potential candidates for dehumidification and heat recovery in solar drying system.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 177〈/p〉 〈p〉Author(s): Xinyue Han, Xiaobin Chen, Qian Wang, Sami M. Alelyani, Jian Qu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nanofluid can be used as an effective spectral beam splitter to enhance the performance of hybrid PV/T system. In this work, we innovatively developed CoSO〈strong〉〈sub〉4〈/sub〉〈/strong〉-based Ag nanofluid which might be utilized as fluid optical filter for hybrid PV/T system with silicon concentrator (CPV) solar cell. Firstly, highly dispersed Ag/CoSO〈sub〉4〈/sub〉 nanofluids with various concentrations were prepared. The results from the measured optical transmittance of the prepared nanofluids show that Ag/CoSO〈sub〉4〈/sub〉 nanofluid has a strong absorption over a broader spectrum than that of water-based one. Subsequently, the effect of Ag nanofluids filters on the electrical performance of the silicon CPV cell was discussed. Ag/CoSO〈sub〉4〈/sub〉 nanofluids produce lower short circuit current and thus lower electrical output than Ag/water nanofluids at the same mass fraction of Ag nanoparticles, whereas they yield higher stagnation temperature than Ag/water nanofluids. A theoretical model for optimizing the optical properties of the nanofluids filters and determining merit function (〈em〉MF〈/em〉) was introduced to evaluate the filtering performance of Ag/CoSO〈sub〉4〈/sub〉 nanofluids in PV/T systems. The results show that the 〈em〉MF〈/em〉 value of PV/T system with Ag/CoSO〈sub〉4〈/sub〉-2 nanofluid filter is greater than both that with a typical Ag-SiO〈sub〉2〈/sub〉 (core-shell)/water nanofluid filter and with a Ag/water nanofluid filter. And the calculated 〈em〉MF〈/em〉 values for PV/T systems with Ag/CoSO〈sub〉4〈/sub〉 nanofluid filters reach a nearly constant value higher than 1.371 when the mass fraction of Ag nanoparticles contained in the Ag/CoSO〈sub〉4〈/sub〉 nanofluid ranging from 24 ppm to 57 ppm. Peak 〈em〉MF〈/em〉 value is achieved when the mass fraction of Ag nanoparticles is 37 ppm.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solar Energy, Volume 177〈/p〉 〈p〉Author(s): Yuanli Lyu, Xuan Wu, Chunying Li, Hua Su, Lijuan He〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Water flow window has been well proven as an efficient way for both solar energy utilization and cooling energy saving for air-conditioned buildings, especially in the cooling-dominant regions. However, investigations on its heating application performance in cold winter season, when the direct solar thermal energy penetration is not sufficient to maintain a comfort room temperature, are quite few. In response, this paper suggests to supply warm water to the window gap and act as heat radiator, in order to help maintaining a suitable indoor thermal environment in winter. In this way, window is no longer the weak point of heat insulation, but a combination of both solar collector and heat radiator. Parametric optimization was completed numerically with a validated FORTRAN program to determine the proper operation parameters. The impacts of water circulation mode, supply water flow rate, warm water temperature and supply period were investigated. With open circulation, the energy saving potential was found to be superior compared to close circulation design with less room heat exchange and improved thermal efficiency. Supply water flow rate of 400 ml/min was recommended for the cases under investigation. The proper temperature of supply warm water varied with the climate, especially the solar intensity. A higher temperature was required for cities with weaker solar radiation and lower ambient temperature. Warm water supply was an effective measure to provide assisted heat source during heating season and the proper supply period was from November to March.〈/p〉〈/div〉 〈/div〉