ALBERT

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Sebastian Iwaszenko, Natalia Howaniec, Adam Smoliński〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Gasification technologies represent the most viable options of thermochemical processing of solid fuels. They are also characterized by lower emissions and higher efficiency when compared to conventional combustion systems. Particular attention has been paid to underground coal gasification offering the possibility of utilization for energy purposes coal resources otherwise inaccessible for economic or safety reasons. The disadvantage of this process is, however, the difficult control both in terms of technological and environmental aspects. The underground coal gasification process requires investigation of numerous heterogeneous reactions and transport processes, influenced by various process parameters, such as the temperature, type and flow rate of a gasification agent and geological conditions of the georeactor. In the paper a new, alternative way of the determination of kinetics of coal gasification by the Random Pore Model application is proposed. The procedure for determination of model parameters is presented. The structural parameter was estimated on the basis of measurements of char porous structure parameters. The reactivity measurements made for selected Polish coals were applied in determination of kinetic constants. The results of gasification process simulations for determined parameters and Random Pore Model are also given.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Joel Krupa, Rahmatallah Poudineh, L.D. Danny Harvey〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Although renewables in the resource-rich countries of the Middle East and North Africa (MENA) are inconsequential contributors to regional total primary energy supply, recent project developments and overt support from a range of influential regional actors suggest a general trend towards a more environmentally sustainable electricity supply. This trend is driven just as much by economics as other factors, as rapidly falling renewable energy capital costs are complementing favourable policy environments, technical suitability, and concerns around the impacts of anthropogenic climate change and local pollution. Finance is an especially important consideration in this transition, yet it receives insufficient coverage. This paper seeks to remedy this deficiency of academic inquiry by highlighting the case of the Gulf Cooperation Council (GCC) to draw out broader implications for the region. We outline the factors that affect the financeability of projects, review the latest developments in renewable energy finance in the region, and present policy recommendations going forward.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360544218320966-egi10GRBN8M09N.jpg" width="289" alt="Image" title="Image"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Hongxia Zhao, Tianpeng Yuan, Jia Gao, Xinli Wang, Jia Yan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Both conventional and advanced exergy analysis methods were adopted to compare parallel and series compression-ejection hybrid refrigeration system for a two-temperature R290 refrigerator. The calculation was performed through Matlab and CoolProp. The results over typical design conditions showed that the exergy efficiency of the series system is 5.17% higher than the parallel system, and the exergy destructions of the compressor (30.59% for parallel and 31.22% for series) and the ejector (19.36% for parallel and 22.65% for series) are the biggest of the total system. Results from advanced exergy analysis showed that the compressor possesses highest improvement priority as its avoidable exergy destruction rate is the biggest, 42.76% of the total for parallel system and 41.28% for series system. The endogenous avoidable exergy destruction rates of the compressor and the ejector are larger than their exogenous parts in both systems, indicating it is most important to improve their own efficiency. However, the condenser’s endogenous avoidable exergy destruction rates are smaller than their exogenous part, so it is more effective by improving other system components rather than itself. The influence of the interactions among the components on the system performance was also evaluated based on their mexogenous exergy destruction.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Yikai Jia, Sha Yin, Binghe Liu, Hui Zhao, Huili Yu, Jie Li, Jun Xu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Dynamic mechanical loading, e.g. impact, is one of the major catastrophic factors that trigger short-circuit, thermal runaway, or even fire/explosion consequences of lithium-ion batteries (LIBs). In this study, the mechanical integrity and electrical coupling behaviors of lithium-ion pouch cells under dynamical loading were investigated. Two types of experiments, namely compression and drop-weight tests, are designed and conducted. The state-of-charge (SOC) and loading rate dependencies of batteries, as well as their coupling effect, are examined. Furthermore, the interaction between force response and electrical behavior of battery is investigated through real-time monitoring of voltage change during loading. Experiments on LiCoO〈sub〉2〈/sub〉 lithium-ion pouch cells show that the higher SOC and loading rates increases battery structure stiffness. In addition, loading rate intensifies battery structure stiffening with the SOC effect. Results indicate that the deformation and material failure of battery component together determine the electrical behavior of battery. Higher loading rate leads to faster voltage drop and more severe internal short-circuit. This short-circuit discharging process in turn affects the force response in dynamic loading. Results may provide useful insights into the fundamental understanding of electrical and mechanical coupled integrity of LIBs and lay a solid basis for their crash safety design.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Tao Yu, Guoqing Guan, Abuliti Abudula, Akihiro Yoshida, Dayong Wang, Yongchen Song〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The 2013/2017 Nankai Trough (Japan) and 2017 Shenhu Area (China) offshore methane hydrate production tests showed the world the possibility and feasibility of the oceanic methane hydrate production by depressurization. However, the relatively low gas production rate still remained as one of the critical bottlenecks for the economical utilization. This study chose the Nankai Trough as a target area, and aimed at the gas recovery enhancement from the methane hydrate reservoir using vertical wells. A traditional single-vertical-well system and a new dual-vertical-well system were proposed, and special production strategies of the aggressive depressurization and permeability improvement were applied to these two systems for the effectiveness verification. Based on the 15-year simulation results, it was found that the middle low-permeability silt-dominated layers in the reservoir held the key to the gas recovery enhancement, and for the single-vertical-well system, the permeability improvement in this sublayer seemed more reliable and feasible than the aggressive depressurization. On the other hand, the dual-vertical-well system significantly exceeded the single-vertical-well system due to the synergistic effect of the two wellbores, and could raise the average gas production rate (9.5 × 10〈sup〉3〈/sup〉 m〈sup〉3〈/sup〉/day) by one order of magnitude (to 7.9 × 10〈sup〉4〈/sup〉 m〈sup〉3〈/sup〉/day). Moreover, if this new system was combined with the aggressive depressurization, the average gas production rate could be further raised by one order of magnitude (to 3.4 × 10〈sup〉5〈/sup〉 m〈sup〉3〈/sup〉/day).〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Dustin McLarty, Nadia Panossian, Faryar Jabbari, Alberto Traverso〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Economic dispatch for micro-grids and district energy systems presents a highly constrained non-linear, mixed-integer optimization problem that scales exponentially with the number of systems. Energy storage technologies compound the mixed-integer or unit-commitment problem by necessitating simultaneous optimization over the applicable time horizon of the energy storage. The dispatch problem must be solved repeatedly and reliably to effectively minimize costs in real-world operation. This paper outlines a method that greatly reduces, and under some conditions eliminates, the mixed-integer aspect of the problem using complementary convex quadratic optimizations. The generalized method applies to grid-connected or islanded district energy systems comprised of any variety of electric or combined heat and power generators, electric chillers, heaters, and all varieties of energy storage systems. It incorporates constraints for generator operating bounds, ramping limitations, and energy storage inefficiencies. An open-source platform, EAGERS, implements and investigates this optimization method. Results demonstrate a 〉99% reduction in computational effort when comparing the newly minted optimization strategy against a benchmark commercial mixed-integer solver applied to the same combined cooling, heating, and power problem.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): F. Giacalone, C. Olkis, G. Santori, A. Cipollina, S. Brandani, G. Micale〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Closed-loop Reverse Electrodialysis is a novel technology to directly convert low-grade heat into electricity. It consists of a reverse electrodialysis (RED) unit where electricity is produced exploiting the salinity gradient between two salt-water solutions, coupled with a regeneration unit where waste-heat is used to treat the solutions exiting from the RED unit and restore their initial composition. One of the most important advantages of closed-loop systems compared to the open systems is the possibility to select ad-hoc salt solutions to achieve high efficiencies. Therefore, the properties of the salt solutions are essential to assess the performance of the energy generation and solution regeneration processes. The aim of this study is to analyse the influence of thermodynamic properties of non-conventional salt solutions (i.e. other than NaCl-aqueous solutions) and their influence on the operation of the closed-loop RED. New data for caesium and potassium acetate salts, i.e. osmotic and activity coefficients in aqueous solutions, at temperature between 20 and 90 °C are reported as a function of molality. The data are correlated using Pitzer's model, which is then used to assess the theoretical performance of the whole closed-loop RED system considering both single and multi-stage regeneration units. Results indicate that KAc, CsAc and LiCl are the most promising salts among those screened.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Giacomo Butera, Søren Højgaard Jensen, Lasse Røngaard Clausen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉The ongoing reduction of greenhouse gas emissions entails increased use of intermittent renewable energy technologies such as wind and solar. This raises the need for cost-effective and efficient electricity storage. In particular seasonal variations in supply and demand will require tremendous storage capacity. In this paper we present a truly large-scale electricity storage system which uses pressurized reversible solid oxide cells combined with catalytic reactors to store electricity as synthetic natural gas. By storing the produced gas in existing natural gas grids the system can create a strong and efficient link between the electricity and gas markets. In addition, the system is able to operate reversibly using gas from the grid to satisfy the electric power demand.〈/p〉 〈p〉The system performance is analyzed with a component-based thermodynamic modeling tool which shows that electricity can be stored as synthetic natural gas with an energy efficiency of 89%. The gas to electricity efficiency is equally high, resulting in a round-trip storage efficiency of 80% (DC-to-DC).〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Yi Liang, Dongxiao Niu, Wei-Chiang Hong〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Along with the deregulation of electric power market as well as aggregation of renewable resources, short term load forecasting (STLF) has become more and more momentous. However, it is a hard task due to various influential factors that leads to volatility and instability of the series. Therefore, this paper proposes a hybrid model which combines empirical mode decomposition (EMD), minimal redundancy maximal relevance (mRMR), general regression neural network (GRNN) with fruit fly optimization algorithm (FOA), namely EMD-mRMR-FOA-GRNN. The original load series is firstly decomposed into a quantity of intrinsic mode functions (IMFs) and a residue with different frequency so as to weaken the volatility of the series influenced by complicated factors. Then, mRMR is employed to obtain the best feature set through the correlation analysis between each IMF and the features including day types, temperature, meteorology conditions and so on. Finally, FOA is utilized to optimize the smoothing factor in GRNN. The ultimate forecasted load can be derived from the summation of the predicted results for all IMFs. To validate the proposed technique, load data in Langfang, China are provided. The results demonstrate that EMD-mRMR-FOA-GRNN is a promising approach in terms of STLF.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Yalian Yang, Huanxin Pei, Xiaosong Hu, Yonggang Liu, Cong Hou, Dongpu Cao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Fuel economy of hybrid vehicles is affected by their powertrain configurations, powertrain parameters, and energy management strategies. It is most beneficial to optimizing all the three factors simultaneously. However, when the design search space is large, an exhaustive, optimal control strategy, such as dynamic programming (DP), is too computationally expensive. Hence, a faster optimization method with higher computational efficiency and acceptable accuracy is required. Based on the DP approach, an approximate optimization method, called rapid dynamic programming (Rapid-DP), is developed and discussed in this paper. This method effectively reduces the decision-making time (the time can be reduced by a factor of 700, compared to the DP approach) for optimal control. The optimization processes and results are described and then compared with the original DP and PEARS + methods under two different driving cycles: FTP72 and HWFET. In conjunction with particle swarm optimization (PSO), the rapid-DP is leveraged, for the first time, to optimize key powertrain parameters for power split hybrid electric vehicles. Based on two power-split hybrids: Toyota Prius and Prius++, the joint optimization approach is exploited to examine vehicular fuel savings attributed to synergistic parameters optimization and operating-mode increase. The multi-mode configuration with optimal component parameters is demonstrated to be most fuel-efficient, with 6.56% and 3.15% fuel reductions under FTP72 and HWFET cycles, respectively, with respect to the original Prius 2010.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Julian David Hunt, Edward Byers, Antonio Santos Sánchez〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In tropical climates, the energy consumed by ventilation and air conditioning can exceed 50% of the total consumption of a building. Demand for cooling is rising steadily, driven mainly by growing incomes in developing economies, and is expected to also increase with climate change. Tropical, coastal areas with narrow continental shelves are good sites for the implementation of Seawater Air Conditioning (SWAC), a renewable and low CO〈sub〉2〈/sub〉 emission cooling process. This paper presents the existing SWAC projects around the world and gives details on the technology. Data on ocean temperature profiles, ocean bathymetry and world surface temperature are processed with the intent of estimating the world potential of SWAC. The results present the required distance from coast to reach seawater with a temperature of 5 °C or less. This is combined with the potential demand for air conditioning, taking into account surface air temperature and a set SWAC design for cooling from 30 to 20 °C. The pipeline length, seawater depth and capacity factor are then used to estimate the costs of SWAC projects around the world. It is concluded that the locations with the highest potential for SWAC are intertropical islands and some continental locations.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Sreten Davidov, Miloš Pantoš〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper presents a significantly improved optimization model for the planning of the charging infrastructure for electric-drive vehicles, where the optimization objective function is the minimization of overall (installation, maintenance, operation) placement costs of charging stations with regards to a charging technology. The constraints involve the electric power system reliability check, ensuring charging reliability and the required quality of service of the charging infrastructure. In ensuring the charging reliability, at least one candidate location must be selected within the driving range of electric vehicles and suitable charging technologies placed to accommodate the disposable charging times of electric vehicle users for the requested quality of service. The proposed optimization model presents an upgrade of an existing optimization formulation since it includes a power system reliability check based on a DC power flow model. To show the general applicability and significance of the model, a test 10 × 10 grid road network and a standard six-bus test power system are considered. Numeric results illustrate the optimal charging stations placement layout and overall costs placement for different driving ranges and the required quality of service level by including a power system reliability check, to serve both the charging infrastructure investors and electric power system operators.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Hongbin Ren, Yuzhuang Zhao, Sizhong Chen, Taipeng Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉the power delivery performance of series and parallel strings connected battery modules or packs is restricted by the worst cells in the string. Each cell has a slightly different capacity and terminal voltage due to manufacturing tolerances and operating conditions. The cell strings tend to loss balance during charging and discharging process. The motivation of this paper is to develop a battery management system (BMS) to monitor and control the temperature, state of charge (SOC) and state of health (SOH) et al. and to increase the efficiency of rechargeable batteries. An active energy balancing system for Lithium-ion battery pack is designed based on the online SOC and SOH estimation. The remainder capacity of the battery is estimated by measuring the terminal voltage for each cell, and the balance system will be triggered when the difference between the SOC of one cell and the average SOC is more or less than a predefined threshold in order to minimize the output voltage ripple. The simulation results indicate that the designed BMS can precisely synchronize the SOC while minimizing the output voltage ripple.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Oliver Ruhnau, Sergej Bannik, Sydney Otten, Aaron Praktiknjo, Martin Robinius〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Energy scenarios provide guidance to energy policy, not least by presenting decarbonisation pathways for climate change mitigation. We review such scenarios for the example of Germany 2050, with a focus on the decarbonisation of heat generation and road transport. In this context, we characterize the role of renewable electricity and contrast two rivalling narratives: direct and indirect electrification. On the one hand, electricity directly provides heat and transport, using electric heat pumps, electric heaters, and battery electric vehicles. On the other hand, electricity, heat, and transport are indirectly linked, using gas heat pumps, gas heaters, fuel cell electric vehicles, and internal combustion engine vehicles, in combination with power-to-gas and power-to-liquid processes. To reach climate policy targets, our findings imply that energy stakeholders must (1) plan for the significant additional demand for renewable electricity for heat and road transport, (2) pave the way for system-friendly direct heat electrification, (3) be aware of technological uncertainties in the transport sector, (4) clarify the vision for decarbonisation, particularly for road transport, and (5) use holistic and more comparable scenario frameworks.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Nan Zhang, Hongjuan Hou, Gang Yu, Eric Hu, Liqiang Duan, Jin Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Solar aided (coal-fired) power generation (SAPG) system has been proved to be an efficient way to utilize the solar energy for power generation. Due to the instability of the solar radiation, a SAPG system generally operates under transient working conditions. In this paper, performance simulation sub-models of main components in a SAPG plant are established based on the lumped parameter assumption. A 330 MW SAPG power plant as a case study is simulated. The variations of the performances, main parameters of the plant with the solar field heat output and the dynamic responses under a typical day are analyzed. The results show that when the heat output of the solar field changes from 0 kJ/h to 2.13 × 10〈sup〉8〈/sup〉 kJ/h, the coal saving rate will increase to 6.4%, and the solar power generation share (the proportion of the power from the solar energy to the total power from the SAPG plant) will increase to 7.74%. During the analysis process, in order to optimize the solar field, the concept of the solar field equivalent efficiency (SFEE) is proposed and the optimal velocity of heat transfer fluid (HTF) in absorber tube is obtained.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Zhendong Zhang, Xiangdong Kong, Yuejiu Zheng, Long Zhou, Xin Lai〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The fast diagnosis of micro-short circuit cells is crucial for the safety of battery packs. Based on the difference between the “median cell” and other cells in a battery pack, we propose a method that can identify micro-short circuit cells under dynamic conditions in real time. We model cell differences and analyze the model from the perspective of its low frequency variation characteristics. We find that approximate open-circuit voltage differences can be obtained when terminal voltage differences are passed through low-pass filters. Then approximate electric quantity differences can be obtained by utilizing the open-circuit voltage differences and the data smoothing function of low-pass filters. For onboard applications of diagnosis method, the recursive least square is adopted to estimate micro-short circuit currents and resistances utilizing the change of electric quantity differences. We verify and analyze the feasibility of the diagnosis method by using simulation data when the cells in a battery pack have temperature, state of charge, capacity, and internal resistance inconsistency, respectively. Finally, the effectiveness of the diagnosis method is further verified by the triggering experiments of micro-short circuits for real battery packs.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Upendra Rajak, Prerana Nashine, Tikendra Nath Verma〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present work encompasses combustion, performance, and emission parameters of experimental investigations of a single cylinder, four stroke, water cooled, direct injection (DI), naturally aspirated compression ignition (CI) engine with a rated power output of 3.7 kW at constant engine speed (1500 rpm) using diesel and different blends of microalgae 〈em〉spirulina〈/em〉. The microalgae 〈em〉spirulina〈/em〉 blend of ratio with diesel (BYY) where YY indicates blending percentage (0%, 20%, 40%, 60%, 80%, and 100% volume basis with diesel respectively) with different engine loading condition (25%, 50%, 75% and 100%) were compared with diesel at CR17.5:1. The output illustrates that the most optimum value is B20% when compared with diesel. The result depicts firstly that there is a reduction in brake thermal efficiency by 0.98%, exhaust gas temperature by 1.7%, hydrocarbon (HC) by 16.3%, carbon monoxide (CO) by 3.6%, NO〈sub〉X〈/sub〉 emission by of 6.8%, and smoke emission by 12.35% respectively. Secondly, there is an increase in specific fuel consumption by up to 5.2% and CO〈sub〉2〈/sub〉 emission by 2.8% for 〈em〉spirulina〈/em〉 blend ratio (B20%) as compared to diesel (B0%) at full load condition engine with constant engine speed.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Isabel Soares, Paula Ferreira, Henrik Lund〈/p〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): K. Kontu, S. Rinne, S. Junnila〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉District heating companies have ambitious targets for lowering carbon emissions in production. Large heat pumps offer an interesting alternative for district heating production allowing utilization of various heat sources. The primary objective of this study is to examine the viability of large heat pumps in existing district heating systems. The study uses three types of systems to simulate how increasing the share of heat pump production influences district heating systems when optimized for the lowest production costs. The second objective of this study is to understand the district heating companies’ perspective on increasing amounts of heat pumps in their systems. Based on the simulations, the largest potential for heat pumps is in small district heating systems, where they reduce the use of fossil fuels. In medium and large systems with economical combined heat and power production, the potential of heat pumps is smaller. The findings of the simulations together with insights from the interviews imply that the viable amount of heat pump based heat production in DH systems would be around 10–25% in Finland, which is much higher than the current 3%.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): A.E. Teo, M.S. Chiong, M. Yang, A. Romagnoli, R.F. Martinez-Botas, S. Rajoo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper presents an equivalent comparison of waste heat recovery method on an internal combustion engine using low-pressure turbine (LPT), turbo compound (TC) & air-Brayton cycle (ABC). A 5.9 L, six cylinders turbocharged diesel engine is used for this case study. All recovery methods are simulated on AVL BOOST where the engine model, turbocharger and heat exchanger are validated with experimental data. It is found that all three methods cannot work effectively without at least reducing the turbocharger turbine size to amplify the compressor surplus power. It is done by using a commercially available turbocharger turbine with smaller area over radius (A/R) volute, hence ensuring the least possible engine hardware change. In all the cases, the engine is ensured to deliver its baseline brake power. It is shown that LPT can recover the most exhaust waste heat (up to 5.40 kW), followed by TC (up to 1.75 kW) and ABC (up to 0.64 kW).〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Mohamed L. Elsayed, Osama Mesalhy, Ramy H. Mohammed, Louis C. Chow〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, exergy analysis of four different feed configurations of a multi-effect desalination with mechanical vapor compressor (MED-MVC) system is initially studied to identify the area of exergy destruction within system components and followed by an exergo-economic study. The feed configurations considered are forward feed (FF), backward feed (BF), parallel feed (PF) and parallel/cross feed (PCF). From the 1st law energy analysis, the PCF and FF configurations require less work to achieve equal distillate production compared to other two configurations. For instance, the specific power consumption (SPC) values are 30.1, 13.7, 23 and 13.9 kWh/m〈sup〉3〈/sup〉 for the BF, FF, PF and PCF configurations, respectively. Changing the feed arrangement from BF to FF and PF to PCF at a constant compression ratio, the total fixed cost for the MED-MVC plant can be reduced by ∼30% and 17%, respectively. Second law efficiency (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈mrow〉〈msub〉〈mrow〉〈mtext〉η〈/mtext〉〈/mrow〉〈mrow〉〈mtext〉II〈/mtext〉〈mspace width="0.25em"〉〈/mspace〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉) calculations show that the PCF (2.9%) has the highest value followed by the FF (2.7%), while the BF (2.4%) exhibits the lowest value among all configurations. The highest exergy destruction (35–50%) occurs within the MVC unit. This can be reduced by limiting the design plant operation to a lower temperature range or increasing the number of effects. Increasing the number of effects for PCF from 1 to 6 results in a 39% reduction in the SPC and a 70% increase in the second law efficiency. Operating at lower steam temperature results in an increase in the 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"〉〈mrow〉〈msub〉〈mrow〉〈mtext〉η〈/mtext〉〈/mrow〉〈mrow〉〈mtext〉II〈/mtext〉〈mo〉,〈/mo〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉 and a decrease in the SPC and total water price (TWP) of the MED-MVC system. Reducing the exergy destruction in the preheaters and the MVC unit is cost-effective for the entire system even with an increase in capital investment costs. Three different cost models are used to estimate the average TWPs for the BF, FF, PF and PCF configurations, and the TWPs are found to be 3.0, 1.7, 2.4 and 1.7 $/m〈sup〉3〈/sup〉, respectively.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Farhad Billimoria, Olumide Adisa, Robert L. Gordon〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Australia's east coast gas market has faced transformational shifts in demand with the commencement of three Liquefied Natural Gas facilities in Queensland. Faced with risks of high domestic prices and potential gas shortages, political intervention has been considered as a possible solution. This paper investigates the impact of network interconnectivity on domestic gas prices by employing a long-term planning model underpinned by mathematical optimisation. At optimal system cost, improved network interconnectivity can provide material and sustained price reductions for the gas market with potential flow-on reductions to the electricity market. Increased connectivity is shown to deliver reductions of over $2/GJ in average gas prices across the eastern seaboard, with a subsequent reduction in electricity prices across all mainland National Electricity Market (NEM) regions. The results also highlight the need to unlock new supply as new transmission projects, though having the potential to reduce gas prices through market connectivity, rely on adequate supply to meet long term demand, and sustain market balance.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Chong Li, Dequn Zhou, Yuan Zheng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The aim of this paper is to evaluate and compare the techno-economic performance of grid-connected photovoltaic (PV) power systems for a rooftop solar PV building containing 14 families in five climate zones in China. The techno-economic performance of grid-connected PV system in the five regions was evaluated using the HOMER software. Monthly average electric production, economic and environmental considerations, and sensitivity analyses were all considered. The results show that the pollutants from grid-only, grid/PV, and grid/PV/battery systems come mainly in the form of CO〈sub〉2〈/sub〉 emissions. In addition, this study concludes that grid/PV systems are technically, economically and environmentally feasible for all five climate zones. The excess electricity, NPC, and COE values of the grid/PV systems for all five climate zones increased with PV penetration increased, whereas the CO〈sub〉2〈/sub〉 emissions for these climate zones decreased due to the increasing PV sizes. For the grid/PV systems of five climate zones, Kunming is the most economical with the least NPC ($113,382) and COE ($0.073/kWh). The lowest CO〈sub〉2〈/sub〉 (38,975 kg/yr), SO〈sub〉2〈/sub〉 (35.4 kg/yr), and NO〈sub〉x〈/sub〉 (165 kg/yr) emissions of grid/PV systems occurred in Kunming. From an economic and environmental perspective, Kunming, with its mild climate conditions, may be especially suitable for grid/PV power generation.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Jinran Wu, Zhesen Cui, Yanyan Chen, Demeng Kong, You-Gan Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Short-term electrical load forecasting is an important part in the management of electrical power because electrical load is an extreme, complex non-linear system. To obtain parameter values that provide better performances with high precision, this paper proposes a new hybrid electrical load forecasting model, which combines ensemble empirical mode decomposition, extreme learning machine, and grasshopper optimization algorithm for short-term load forecasting. The most important difference that distinguishes this electrical load forecasting model from other models is that grasshopper optimization can search suitable parameters (weight values and threshold values) of extreme learning machine, while traditional parameters are selected randomly. It is applied in Australia electrical load prediction to show its superiority and applicability. The simulation studies are carried out using a data set collected from five main states (New South Wales, Queensland, Tasmania, South Australia and Victoria) in Australia from February 1 to February 27, 2018. Compared with all considered basic models, the proposed hybrid model has the best performance in predicting electrical load.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360544218320668-fx1.jpg" width="427" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): X.Y. Chen, R.R. Chen, X. Ding, H.Z. Fang, X.Z. Li, H.S. Ding, Y.Q. Su, J.J. Guo, H.Z. Fu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In order to improve hydrogen storage properties of Ti〈sub〉23〈/sub〉V〈sub〉40〈/sub〉Mn〈sub〉37〈/sub〉 alloy with the two-phase mixture of BCC and C14 Laves, the alloys with different Zr (〈em〉x〈/em〉 = 0, 2, 4, 6, 8 and 10, at.%) partly substituting for Ti have been produced. The results show that the primary (dendrite) BCC phase decreases and C14 Laves phase increases with increasing Zr. The secondary (blocky) BCC phase appears when Zr content is more than 6 at.%. The hydrogen absorption rate increases after completely activated because the Zr improves the formation of C14 Laves phase. Meanwhile, the reversible hydrogen capacity of Zr-substituted alloys is higher than that of Zr-free alloy. The effective hydrogen storage capacity reaches the maximum when the composition is Ti〈sub〉21〈/sub〉Zr〈sub〉2〈/sub〉V〈sub〉40〈/sub〉Mn〈sub〉37〈/sub〉, with a value of 1.85 wt.% at 293 K. Two desorption plateaus appear when Zr content is more than 6 at.%, and the width of the higher plateau increases with increasing of Zr. The higher plateau results from the fast diffusion of H atom in the smaller secondary BCC phase. With increasing the Zr content, the hysteresis and plateau slope factor increase, which can be attributed to the increasing strain energy of interstitial sites and the affinity of interstitial sites with H.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Yonghong Jiang, Cheng Jiang, He Nie, Bin Mo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We study the dynamic relationship between the global oil market and China's commodity market at the industry level by using a DCC-GJR-GARCH model. Results of this study reveal strong return spillovers and the long-term time-varying linkages in volatility between the global oil market and China's commodity sectors. We find evidence that the diversified portfolios can help us reduce risks effectively, and the performances of portfolio diversification strategies vary across different time periods. Our empirical results highlight that the oil-commodity sectors nexus can help investors minimize risks to build optimal portfolios.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Murat Kadir Yesilyurt, Tanzer Eryilmaz, Mevlüt Arslan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, engine performance, exhaust emissions and combustion behaviors of a single-cylinder, four-stroke, direct-injection diesel engine running on biodiesel/diesel/1-butanol and biodiesel/diesel/n-pentanol fuel blends were investigated and compared with diesel fuel under different engine speeds and full load operating conditions. Test fuels were prepared with 5 and 10 vol% 1-butanol and n-pentanol. Engine test results indicated that brake powers and torques decreased as the amount of alcohol increased, while BSFC increased between 0.77% and 8.07%. Alcohol blended fuels acquired lower EGT and CO〈sub〉2〈/sub〉, while observing higher O〈sub〉2〈/sub〉 emission due to high oxygen content of alcohol compared to diesel fuel. Alcohol treated blends also diminished NO〈sub〉X〈/sub〉 by 0.56–2.65%, CO by 6.90–32.40%, and smoke by 10.47–44.43%. Moreover, n-pentanol blended fuels showed better performance and emission results than 1-butanol blends. Maximum in-cylinder pressure of higher alcohol blended fuels found between 94.55 and 95.82 bar at 371-372〈sup〉o〈/sup〉CA for 1400 rpm, and between 78.19 and 82.19 bar at 375-376〈sup〉o〈/sup〉CA for 2600 rpm. Alcohol addition into the blends increased maximum in-cylinder pressure up to 1.38% at low speed, whereas it decreased up to 3.75% at high speed. Furthermore, higher HRR values up to 8.5% were observed with the alcohol mixed fuels. Consequently, higher alcohols (n-pentanol and 1-butanol) can be utilized as alternative additives in biodiesel/diesel blends for diesel engines to improve emissions, although they adversely influence engine performance.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Xiaolin Tang, Dejiu Zhang, Teng Liu, Amir Khajepour, Haisheng Yu, Hong Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, motor torque control methods are proposed to suppress the vibration of a dual-motor hybrid powertrain during start-stop operation. Firstly, a co-simulation ADAMS and MATLAB/SIMULINK model is built to study the dynamic characteristics of the hybrid vehicle during modes switching process. Secondly, a torque compensation control method of electric motors is established to compensate the vibration energy source. Thirdly, a vibration transfer path control is built to change the dynamic properties during the engine start-stop process. The results show that the proposed methods can reduce the longitudinal acceleration amplitude of the vehicle to less than 0.4 m/s〈sup〉2〈/sup〉, which is only about 30% of the uncontrolled system, during the engine start process. While in the engine stop process, the longitudinal acceleration amplitude of the vehicle is reduced to less than 0.3 m/s〈sup〉2〈/sup〉, and the vibration amplitude is only about 20% of the unchanged system. The established methods are effective for suppressing the vehicle vibration and controlling the energy during the modes switching.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 167〈/p〉 〈p〉Author(s): Tianbiao He, Zuming Liu, Yonglin Ju, Ashak Mahmud Parvez〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper aims to offer some criterions on selecting liquefaction process for small-scale mobile LNG plant. To this end, a comprehensive optimization and comparison was presented to show quantitive results on modified mixed refrigerant liquefaction process (MSMR) and parallel nitrogen expansion liquefaction process (PNEC) from the perspectives of specific energy consumption, exergy efficiency, techno-economy and operational flexibility. First, the MSMR and PNEC were optimized by using two different objective functions, namely minimizing specific energy consumption and total investment. The results showed that the minimum specific energy consumption of MSMR and PNEC were 0.411 kWh/kg and 0.618 kWh/kg, respectively. Then, the exergy efficiency comparison demonstrated that the exergy efficiency of MSMR reached 49.96%, while that of PNEC was only 33.19%. Furthermore, the techno-economic comparison was investigated on the small-scale mobile LNG plant by using total investment (TI) model in 20 years life cycle. The total investiment of MSMR was $6,126,133, while that of PNEC was $8,379,177. The total investiment of MSMR was 26.88% lower than that of PNEC, which indicated that MSMR had a better techno-economic performance than PNEC. Finally, the flexibility study was adopted to compare the capability of handling different feed gas conditions for liquefaction. The comparison results showed that MSMR had a lower specific energy consumption, higher exergy efficiency, lower total investment, and higher flexibility than PNEC. In conclusion, MSMR is a better choice for small-scale mobile LNG plant from the four perspectives.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Tanmay Jain, Pratik N. Sheth〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Biomass is a major source of fuel in many developing countries and used in cook stoves. The water boiling test or its variants are used to evaluate the performance. The evaluation is on an average basis throughout the test and does not provide the dynamics of the energy transfer process. To provide a better insight on this transfer process, the present study demonstrates energy utilization test, which enables analysis of the performance parameters with respect to time. The WBT experimental set up is modified to measure the variation of biomass fuel consumption and water evaporation separately with time by incorporating the separate top mounted weighing balance. The new variable, weight of the water pot, variation with time is also observed along with other standard WBT variables. This new test is validated by performing several experiments. It provides insights on the time-dependent behavior of thermal efficiency and other parameters when performed at different air flow rates. Based on the test results, a new air flow recipe is developed which provides better performance and outlines the significance of energy utilization test. With the formulated recipe, the runtime has improved to nearly 85 min which is an increase of more than 30%.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Touria Moudakkar, Z. El Hallaoui, S. Vaudreuil, T. Bounahmidi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The use of a parabolic collector trough (PTC) array to supply the heat requirement of a phosphate flash dryer is investigated. To evaluate the thermal performances of a PTC array operating between 200 and 550 °C, new heat transfer models were developed. These models, considering either a uniform or a non-uniform distribution of the solar flux, were adapted from basic models by including more accurate correlations while considering longitudinal variations of the convective term. Simulations of the PTC array were conducted for various solar loops, using different heat transfer fluids (HTF). Simulated results from both models are in good agreement with experimental data, with the uniform model predicting HTF outlet temperature at a maximum uncertainty of 0.3 °C. This value jumps to 1.7 °C when gas is used as HTF or when the solar loop exceeds 700 m in length. From a Fisher test standpoint, these results can be considered as comparable to those obtained from more complicated models. Using these new models, the output of a PTC prototype was estimated and served as the basis to predict the yield of a coupled bench scale flash dryer unit.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Olumide Olumayegun, Meihong Wang, Eni Oko〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Power generation from coal-fired power plants represents a major source of CO〈sub〉2〈/sub〉 emission into the atmosphere. Efficiency improvement and integration of carbon capture and storage (CCS) facilities have been recommended for reducing the amount of CO〈sub〉2〈/sub〉 emissions. The focus of this work was to evaluate the thermodynamic performance of s-CO〈sub〉2〈/sub〉 Brayton cycles coupled to coal-fired furnace and integrated with 90% post-combustion CO〈sub〉2〈/sub〉 capture. The modification of the s-CO〈sub〉2〈/sub〉 power plant for effective utilisation of the sensible heat in the flue gas was examined. Three bottoming s-CO〈sub〉2〈/sub〉 cycle layouts were investigated, which included a newly proposed single recuperator recompression cycle. The performances of the coal-fired s-CO〈sub〉2〈/sub〉 power plant with and without carbon capture were compared. Results for a 290 bar and 593 °C power cycle without CO〈sub〉2〈/sub〉 capture showed that the configuration with single recuperator recompression cycle as bottoming cycle has the highest plant net efficiency of 42.96% (Higher Heating Value). Without CO〈sub〉2〈/sub〉 capture, the efficiencies of the coal-fired s-CO〈sub〉2〈/sub〉 cycle plants were about 3.34–3.86% higher than the steam plant and about 0.68–1.31% higher with CO〈sub〉2〈/sub〉 capture. The findings so far underscored the promising potential of cascaded s-CO〈sub〉2〈/sub〉 power cycles for coal-fired power plant application.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360544218321236-egi10322KNZS13.jpg" width="338" alt="Image" title="Image"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): L. Yu, Y.P. Li, G.H. Huang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Rapidly increased coal consumption has caused dramatically pollutants and carbon dioxide (CO〈sub〉2〈/sub〉) emissions, such that utilizing renewable energy to substitute high pollutant and carbon fuels is crucial to fulfill sustainable development. In this study, an interval possibilistic-stochastic programming (IPSP) method that is capable of dealing with multiple uncertainties existed in the real-world mixed energy system (MES) is developed. Then, the IPSP method is applied to planning MES in the City of Qingdao (China) that aims to encourage developing renewable energies based on subsidy policy. Solutions under varied subsidies for stimulating renewable energies in association with different probabilities and 〈em〉α〈/em〉 levels have been generated, which can help determine the optimized electricity generation and supply that could hedge appropriately against system violation risk. Compared to the results without subsidy, renewable energies with subsidy policy can increase by [2.4, 3.2] % and the share of renewable energies would raise to 17.5% at the end of planning horizon. The findings can provide useful information for the other municipal-scale MES planning issues to facilitate policy enactment of renewable energy, improvement of energy supply security, as well as accomplishment of planning environmental and sustainable MES.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Neil Evans, Calvin Jones, Max Munday, Meng Song〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The paper examines the potential regional economic benefits of the development of unconventional gas. Wales (UK) represents an interesting lens through which to examine the expected effects of unconventional gas developments. In spite of significant resource endowments the region has found it difficult to internalise the economic benefits from prior energy developments. We examine whether possible commercial exploitation of unconventional gas in Wales will be any different from recent rounds of resource and energy investment. We address the challenges for resource peripheries in embedding economic activity linked to unconventional gas and show that there are dangers in generalising economic impact evidence from other states.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Q. Chen, M. Kum Ja, Y. Li, K.J. Chua〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Integrating thermal desalination systems with vapor compression is an effective way to improve the energy efficiency. This paper investigates a spray-assisted low-temperature desalination system that is integrated with a thermal vapor compression system (SLTD-TVC). A detailed thermodynamic model is judiciously developed based on the principles of heat and mass transfer, heat balance, mass balance, and exergy balance. Applying the model, the energy efficiency of the combined SLTD-TVC process is first evaluated. The production ratio of the combined system is found to be 10–35% higher than that of the conventional SLTD process. Accordingly, an exergy analysis is conducted to quantify the sources of irreversibility within the system. The steam jet ejector is found to be the major source of thermodynamic irreversibility, accounting for more than 40% of the exergy destruction. The overall system efficiency is improved at a lower motive steam pressure, a higher number of operating stages and a medium cooling water flowrate. Finally an economic analysis is carried out, which reveals that the changes of both initial plant cost and operation cost are marginal after the integration of the thermal vapor compression system.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Bingzheng Dou, Michele Guala, Liping Lei, Pan Zeng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The wake of upstream wind turbines is known to affect the operation of downstream turbines and the efficiency of the wind farm. In this study, a systematic experimentation on performance and wake spatial evolution was carried out using a wind turbine model varying tip speed ratio, pitch and yaw angles. The change of pitch angle was observed to induce a greater effect on the wake velocity as compared to the tip speed ratio. This is interpreted in terms of “force viewpoint”, which describes more quantitatively the relationship between the turbine performance and the wake, as compared to the “power viewpoint”, based on the sole energy conversion. The turbine yaw angle is observed to cause not only a decrease in power and thrust, but also an offset and an asymmetry in the wake. The offset, quantified using the spatial distribution of the velocity minima, is modeled analytically. Comparisons of model estimations with the experimental measurements show that the proposed model can acceptably predict the wake offset of a yawed turbine. The observed dependencies of the mean velocity deficit and wake turbulence on power, thrust, and yaw angle, may suggest new derating strategies for wind farm optimization.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Chang Liu, Yujie Wang, Zonghai Chen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Lithium-ion battery/ultracapacitor hybrid energy storage system is capable of extending the cycle life and power capability of battery, which has attracted growing attention. To fulfill the goal of long cycle life, accurate assessment for degradation of lithium-ion battery is necessary in hybrid energy management. This paper proposes an improved degradation model of lithium-ion battery based on the electrochemical mechanism of capacity fade, in which the influence of cycling current is taken into consideration. Moreover, genetic algorithm is applied to identify the initial values of model parameters. A particle filter based data driven framework is also designed to track the variation of model parameters and states during the cycling process. Short-term and long-term degradation prediction methods are then developed, to forecast the essential indicators of battery health. Datasets of battery cycling tests under both constant cycling current and dynamic cycling current are used for verification. The root mean square error results for state of health prediction (less than 18 cycles) and remaining useful life prediction are below 8% and 40 cycles, respectively, showing the accuracy and applicability of the proposed methods. Additionally, the baseline degradation prediction for case with cycling current information unknown is also illustrated.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Zhang Kun, Demin He, Jun Guan, Qiumin Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A poly-generation system integrating coal pyrolysis and chemical looping gasification (CLG) is proposed to realize the multi-generation of value-added chemicals, synthetic gas fuels and heat/electricity. In this system, the models including coal pyrolysis, coal drying, air reactor (AR) and fuel reactor (FR) are employed to simulate the coupled system using Aspen Plus software. Especially, the FR model is used to produce syngas, which is the main target product, on the basis of Gibbs free energy minimization approach. According to the thermodynamic data obtained from the simulation, chemical exergy and physical exergy are determined for process streams and thermal efficiency is discussed as well. The overall energy efficiency of the new system can achieve values of 43.12%, with the drying unit causing the highest energy destruction. The results indicate that the coupled system shows a better performance compared with its original individual processes in consideration of the thermodynamic efficiency and effects on the environment, though the additional mechanical energy consumption occurs in the new system. Moreover, being used as the gasification agent in the FR, phenol wastewater has been greatly reduced, which reduces levels of environmental pollution. Hence, this new system will be of great potential in industrial application due to its high energy utilization efficiency and low pollution.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Shaobo Xie, Xiaosong Hu, Teng Liu, Shanwei Qi, Kun Lang, Huiling Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper presents a new integrated model predictive control (IMPC) method that combines power management and adaptive velocity control during vehicle-following scenarios in reality, for a plug-in hybrid electric vehicle (PHEV). Innovatively, the IMPC is able to plan the battery state of charge (SOC) and vehicular velocity trajectories, in order to improve fue economy and driving safety. To assess the performance of the IMPC, a comparison is performed with common charge-depleting and charge-sustaining (CDCS) and DP-based energy management strategies, where an improved full velocity difference model (IFVDM) is incorporated to simulate vehicle-following behavior. These solutions are examined using a real-world driving cycle. The results reveal an enormous potential of flexibly tuning the inter-vehicle distance to increase fuel economy. This is distinct from the rigid vehicle-following behavior of the IFVDM just for driving safety. Moreover, the proposed IMPC can ensure the battery charge depletion at the end of the trip. The quantitative results witness that the total cost of the IMPC with a preview horizon of 3s can be reduced by 17.9% and 36.1% for a 70 km city-bus route, compared to IFVDM-based DP and CDCS counterparts, respectively. In addition, the effect of the preview-horizon length on both fuel economy and computational time is examined.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Danial Baghernezhad, Majid Siavashi, Ali Nakhaee〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Steam-assisted gravity drainage (SAGD) is a commonly used thermal enhanced oil recovery (EOR) method in heavy oil reservoirs. Scenario optimizations are conducted with different optimization techniques to determine the optimal steam injection rate and temperature strategies. The performance of standard artificial bee colony (SABC), directed ABC (DABC), generalized pattern search (GPS) and mesh-adaptive direct search (MADS) algorithms were investigated. Also, the effect of initial guess and polling type on the performance of GPS and MADS were analyzed. DABC approaches the global optimum better than other employed algorithms, with a huge number of function evaluations. While, GPS is the fastest algorithm, likely to be trapped in local extrema. To eliminate this issue, the novel multi-region pattern search (MRPS) algorithm is proposed, in which the search space is divided into smaller subregions, each one is searched independently. Hence, search space is more efficiently explored and initial guess dependency is reduced. MRPS algorithm provided similar results to the DABC algorithm while lowering the computational costs up to 93%. MRPS algorithm is successfully applied for a 5-year SAGD scenario optimization. Furthermore, by scenario optimization, SAGD operation could be reduced for 1-year, providing the same NPV as that of the reference case operating for 4-years.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): A.V. Chistyakov, S.A. Nikolaev, P.A. Zharova, M.V. Tsodikov, F. Manenti〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, Cu/Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 catalysts with different metal loadings was applied for the direct ethanol conversion into linear α-alcohols in the supercritical regime. 5% Cu/Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 catalyst was found to provide ethanol conversion into 1-butanol, 1-hexanol and 1-octanol with 80.2% selectivity of 1-butanol or total selectivity of linear α-alcohols of 95.5 at 33.5% conversion of ethanol. The supercritical conditions allow to increase catalysts productivity in comparison with subcritical regime. Kinetic features of the reaction and the effect of water content in the feed mixture were investigated.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Bing Gong, Xiaochen Zheng, Qing Guo, Joaquín Ordieres-Meré〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉This paper explores the effects of enforced Chinese policies regarding environmental matters at the provincial level. The paper proposes several features and explores datasets from the last four Five-Year Plans, which extensively covered the period from 1995 to 2015.〈/p〉 〈p〉As the datasets are multidimensional, dimensional reduction is applied with a control of information loss described by data variance preservation. A data-based clustering algorithm is applied to identify the similarities, and characteristics are explored in relation to the specific features.〈/p〉 〈p〉The use of this method makes it possible to identify the changes in the relevance of the features in the most recent Five-Year Plan, in which decarbonization is relevant instead of productivity. This method also makes it possible to identify specific efforts several provinces have made to introduce cleaner energy production.〈/p〉 〈p〉Following the analysis, it is concluded that the proposed features enable the proposed method to be considered a tool for analyzing the real-world effects of the adopted policies.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Qiang Wang, Kun Luo, Renyu Yuan, Sanxia Zhang, Jianren Fan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To ameliorate the efficiency of wind farms, except assessing the wake effect between the wind turbines, the wake interference between the wind farms must be considered. Based on the Weather Research and Forecasting (WRF) model, the overall performance and power output characteristics, and wake interference effects between the adjacent wind farms in Hami region of Xinjiang province under real terrain and atmospheric conditions were investigated. The wind turbine drag parameterization (WTDP) scheme was elaborated. The results show that the wake of the whole field generally recovers at downstream 16.5 km under prevailing wind direction and annual average wind speed, and the frequency of power output around the rated power is up to 30%. Moreover, the disturbance induced by the wake effect of a large-scale wind farm on its downstream adjacent farm was quantitatively evaluated. Due to the impact of the upstream farm, the wake distance of the downstream wind farm is doubled. The influence on the power output presented a regularity of day-night alternation, with a higher frequency of great loss at night, dawn and evening. The average relative loss ratio reached 5.8%. This study is expected to provide a theoretical basis and engineering guidance for micrositing of wind farms.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Pieter Billen, Enrica Leccisi, Subham Dastidar, Siming Li, Liliana Lobaton, Sabrina Spatari, Aaron T. Fafarman, Vasilis M. Fthenakis, Jason B. Baxter〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Lead halide perovskites (LHP) are an emerging class of photovoltaic (PV) materials that have drawn intense interest due to their power conversion efficiencies above 23% and their potential for low-cost fabrication. However, the toxicity of lead causes concern about its use in LHP-PV at large scales. Here, we quantified lead intensity and toxicity potential of LHP-PV in potential commercial production. Lead intensity in LHP-PV life cycles can be 4 times lower and potential toxic emissions can be 20 times lower than those in representative U.S. electricity mixes, assuming that PV operational lifetimes reach 20 years. We introduce the metric “toxicity potential payback time”, accounting for toxic emissions in the life cycle of energy cycles, and showed that it is 〈 2 years for perovskite PVs produced by and displacing the same grid mix. The toxicity potential associated with the energy of manufacturing a PV system dominates that associated with release of embodied lead. Therefore, the use of lead should not preclude commercialization of LHP-PVs. Instead, effort should focus on development of low-energy manufacturing processes and long service lifetimes. Additional detailed investigations are needed to quantify the full life cycle of commercial production of perovskites and to minimize potential emissions.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360544218321364-fx1.jpg" width="290" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Rasmus Østergaard Gadsbøll, Lasse Røngaard Clausen, Tobias Pape Thomsen, Jesper Ahrenfeldt, Ulrik Birk Henriksen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As increasing amounts of wind and solar are integrated into the energy system, there is a growing need for the development of flexible and efficient biomass-based energy plants. Currently, a Polygeneration concept is being investigated: a system based on thermal biomass gasification and solid oxide cells that can either produce power or biofuels depending on the electricity prices. This study investigates gasifier design opportunities for large-scale and fuel flexible TwoStage concepts that only applies partial oxidation for tar conversion. Thermodynamic modeling is carried out for a total of 12 gasifier cases, featuring 3 main systems that each can process wood/straw and use air/oxygen. It was found that despite the varying operation conditions, process parameters remained relatively stable and that partial oxidation could be effectively applied as the only tar reducing measure. The systems all achieved high cold gas efficiencies of 84–88% and were found to be significantly more effective than competing technologies, while also obtaining higher fuel flexibility.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): E. Medina-López, A. Moñino, R.J. Bergillos, M. Clavero, M. Ortega-Sánchez〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper presents a complete methodology for an integrated simulation of the influence of seabed morphology on the performance of Oscillating Water Column wave energy converters. Different wave characteristics are tested, particularly storm and post-storm conditions. The simulation domain is set in ANSYS Fluent〈sup〉®〈/sup〉, where the changes in seabed under different wave conditions are implemented. The turbine is simulated in terms of pressure drop and pneumatic performance by an Actuator Disk Model (ADM). Results show that the efficiency in energy extraction in the OWC is directly influenced by the equilibrium states of the seabed linked to the storm evolution.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Magnus Dahl, Adam Brun, Gorm B. Andresen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Goals to reduce carbon emissions and changing electricity prices due to increasing penetrations of wind power generation affect the planning and operation of district heating production systems. Through extensive multivariate sensitivity analysis, this study estimates the robustness of future cost-optimal heat production systems under changing electricity prices, fuel cost and investment cost. Optimal production capacities are installed choosing from a range of well-established production and storage technologies including boilers, combined heat and power (CHP) units, power-to-heat technologies and heat storages. The optimal heat production system is characterized in three different electricity pricing scenarios: Historical, wind power dominated and demand dominated. Coal CHP, large heat pumps and heat storages dominate the optimal system if fossil fuels are allowed. Heat pumps and storages take over if fossil fuels are excluded. The capacity allocation between CHP and heat pumps is highly dependent on cost assumptions in the fossil fuel scenario, but the optimal capacities become much more robust if fossil fuels are not included. System cost becomes less robust in a fossil free scenario. If the electricity pricing is dominated by wind power generation or by the electricity demand, heat pumps become more favorable compared to cogeneration units. The need for heat storage more than doubles, if fossil fuels are not included, as the heating system becomes more closely coupled to the electricity system.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Yingxian Xue, Mingyang Yang, Ricardo F. Martinez-Botas, Alessandro Romagnoli, Kangyao Deng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper investigates performance and loss mechanism of a nozzled twin-entry mix-flow turbine at different admissions. Two sets of partial admissions and unequal admissions are analysed via experimentally validated numerical method. Results show that discrepancies of turbine efficiency between symmetrical unequal admissions (swopping inlet pressure on two entries) increase when unequal admissions approach to partial admissions, although their swallowing capacity is similar. Loss breakdown of turbine shows that loss is higher in nozzle but lower in rotor when the majority of flow is fed from upper part of the component (near shroud). Opposite phenomenon happens when the majority is fed from lower part (near hub). The reason for loss characteristic of nozzle is front-sweep configuration of the nozzle vane which results in evident flow separation when the flow is fed near the shroud. The reason for loss characteristic of rotor is the tornado-shaped vortex when the flow is fed from the hub. The tornado vortex is initiated by large incidence angle near hub and developed by the combination of Coriolis force, pressure gradient and centrifugal force. The study unveils loss mechanism among different admissions for a twin-entry turbine, which may enlighten the design methodology of the turbine with twin-entry volute.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 166〈/p〉 〈p〉Author(s): Eren Sevinchan, Ibrahim Dincer, Haoxiang Lang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, energy and exergy analyses of a biogas driven multigeneration system is conducted for performance assessment and evaluation. In this regard, the multigeneration system with a biomass digestion process is developed for this purpose. Multigeneration system consists of different subsystems, such as two-stage biomass digester, open-type Brayton cycle, Organic Rankine Cycle (ORC), single-effect absorption chiller, heat recovery, water separation unit. This multigeneration system aims to generate electrical power for at least 300 houses, heating power for five greenhouses, cooling power and product water from flue gas for agricultural consumption in greenhouses. The results indicate that the overall energy efficiencies of the proposed system is 72.5% with 1078 kW electrical, 198 kW heating, and 87.54 kW cooling power, and daily around 40 kg water production. However, the maximum exergy efficiency of the multigeneration system is obtained as 30.44%, with 65% of the highest exergy destruction rate in combustion chamber.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Venugopal Reddy Bodha, A. Srujana, O. Chandrashekar〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Power conversion systems are used in wind turbine to improve the quality of the generated power without harmonic distortion which is utilized for transmission through grid intended for variable wind speed. However due to the variations of wind leads to evolving of high voltage and low voltage which leads to inconsistency in feeding power to grid. Inorder to provide quality constant harmonic distortionless power to grid from wind turbine an efficient Magnet Synchronous Generator (MSG) connected to the Modified H-bridge series connected Voltage Source Convertor (MHSVSC) is framed out. This converter can draw the input voltage with low distortion and thereby provides the output voltage with low harmonic distortion by LCL filter. Also, to meet the inconsistency in voltage supply to the grid, a fault ride requirement capability based on the M-controller is provided for the dc-link voltage to manage the voltage drop and over voltage in the grid. Thus, the power, which is to be supplied to the grid, is done cost efficiently, consistently, reduced harmonic distortion and errors by utilizing the MHSVSC with Fault Ride Capability. The proposed methodology implemented in the MATLAB platform.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part A〈/p〉 〈p〉Author(s): Michał Leśko, Wojciech Bujalski, Kamil Futyma〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉The aim of this document is to present the topic of operational optimization in District Heating (DH) systems, with special focus on different kinds of thermal energy storage. An optimization solution based on solving multiple Mixed Integer Linear Programming (MILP) problems has been proposed and implemented in the R programming environment.〈/p〉 〈p〉The operational optimization in a DH system, especially if this system is supplied from a combined heat and power (CHP) plant, is a difficult and complicated task. Finding a global financial optimum requires considering long periods of time and including thermal energy storage possibilities into consideration. There are three important solutions for thermal energy storage: hot water tanks, utilization of thermal inertia of the network itself and utilization of thermal inertia of buildings. Each of these solutions has its advantages and disadvantages, and they can be combined to reach the maximum flexibility at lowest cost. However, modeling of operation with all of the thermal energy storage possibilities in place is a complicated task, since they influence the transient behavior of the network in different ways, and affect each other. On the other hand, optimal planning of heat production can be done only if simple and robust simulation models are available. Proposed solution allows simulation of three kinds of thermal energy storage, with their specific transient behaviors and interactions, at the same time keeping the model simple and ready to be used with a MILP solver. An iterative approach has been applied to non-linear phenomena, which allows solving a non-linear problem by multiple MILP optimizations. It has been successfully implemented in the “R” programming environment and tested on a simple example. The results can prove useful for DH system operators in the near future.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part A〈/p〉 〈p〉Author(s): M.V. Navarro, J.M. López, A. Veses, M.S. Callén, T. García〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The characteristics of bio-oil produced from biomass pyrolysis can be improved by co-feeding waste materials. In this work, co-pyrolysis of lignocellulosic biomass with six different waste plastics (waste tyre (WT), polylactic acid (PLA), polystyrene (PS), polyethylene terephthalate (PET), polypropylene (PP) and high density polyethylene (HDPE)) were conducted in a thermogravimetric analyser to study thermal decomposition of the mixtures. The distributed activation energy model (DAEM) was applied to pure feedstocks at 5 and 10 °C/min heating rates to fit the kinetic parameters. The model was used to simulate the co-pyrolysis of biomass/plastic mixtures assuming additive effect of components at different weight proportions and heating rates. Profiles of the fraction of mass remaining for mixtures at 100 °C/min were reproduced with a remarkable agreement. Discrepancies between the experimental and calculated profiles were considered as a measure of the extent of interactions occurring in the co-pyrolysis. Projections of the behaviour of mixtures under flash pyrolysis conditions were performed to study important aspects of the process, such as radical interactions and optimum working temperature.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Nayyar Hussain Mirjat, Muhammad Aslam Uqaili, Khanji Harijan, Gordhan Das Walasai, Md Alam Hossain Mondal, Hasret Sahin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Pakistan is facing electricity crises owing to lack of integrated energy planning, reliance on imported fuels for power generation, and poor governance. This situation has challenged governments for over a decade to address these crises. However, despite various conformist planning and policy initiatives, the balance between demand and supply of electricity is yet to be achieved. In this study, Long-range Energy Alternatives Planning System (LEAP) is used to develop Pakistan's LEAP modeling framework for the period 2015–2050. Following demand forecast, four supply side scenarios; Reference (REF), Renewable Energy Technologies (RET), Clean Coal Maximum (CCM) and Energy Efficiency and Conservation (EEC) are enacted considering resource potential, techno-economic parameters, and CO〈sub〉2〈/sub〉 emissions. The model results estimate the demand forecast of 1706.3 TWh in 2050, at an annual average growth rate of 8.35%, which is 19 times higher than the base year demand. On the supply side, RET scenario, although capital-intensive earlier in the modeling period, is found to be the sustainable electricity generation path followed by EEC scenario with the lower demand of 1373.2 TWh and minimum Net Present Value (NPV) at an aggregate discount rate of 6%. Conclusion section of the paper provides the recommendations devised from this study results.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Yongqiang Luo, Ling Zhang, Zhongbing Liu, Lei Xie, Xiliang Wang, Jing Wu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this research, a double skin facade integrated with amorphous silicon photovoltaic blinds (PVB-DSF) is experimentally investigated. This structure can fulfill multiple functions of the power generation in situ and lowering heat gain or loss through glazing. The experiment rig was built to investigate the thermal and electrical performance of PVB-DSF system. The performance difference between ventilation and non-ventilation mode of PVB-DSF is first analyzed. Then thermal performance of PVB-DSF is demonstrated by comparison with traditional opaque façade (brick wall) and semi-transparent glazing facade (double skin façade) in winter conditions. The results demonstrate that PVB-DSF can reach much higher solar heat gain coefficient (SHGC) and lower heat transfer coefficient in non-ventilation mode. PVB-DSF can save about 1121 Wh/(m〈sup〉2〈/sup〉day) of heating energy in winter compared with the brick wall. By average value, the heat gain of PVB-DSF could be 73.74% higher than conventional DSF in winter. In addition, another type of semi-transparent PV-DSF is also compared with PVB-DSF. The results suggest that PVB-DSF can achieve better thermal performance but lower power generation efficiency comparing to semi-transparent PV-DSF.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Aleksandr M. Kler, Elina A. Tyurina, Aleksandr S. Mednikov〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The paper is devoted to complex technical and economic studies of the large-scale combined production of methanol and electricity based on brown coal. The proposed solution is based on coal gasification in a fluidized bed gasifier with steam-oxygen as a gasification agent, three-stage catalytic synthesis of methanol, and a combined cycle. Detailed, effective mathematical models of combined methanol-electricity production plant (CMEPP) and its components are developed. Optimization studies on the mathematical model of the plant are carried out, optimal flow diagrams and parameters of the CMEPP are obtained. The sensitivity of optimal variant to the change in the external economic conditions is estimated. The conditions for the CMEPP competitiveness are shown.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Houria Smail, Rezak Alkama, Abdellah Medjdoub〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The network of a wind farm is composed of an internal medium voltage grid which represents several wind turbines and substations, and a high voltage transmission system. The capital cost of the internal grid constitutes a significant part of the total cost of the farm. Thus designing the optimal architecture of a wind farm is a key element in the profitability of a project. In this context, this paper presents a novel solution algorithm for connecting the internal grid of a wind farm. This algorithm is based on a combination between genetic algorithm and a specific algorithm. Genetic algorithm is used to optimize both the position of the electrical substation and the number of its cable feeders, whereas the specific algorithm considers the shortest distance to connect the wind turbines between them and the electrical substation. The proposed approach is tested on a real model of wind farm; the obtained results proved that the proposed algorithm is usefulness during the planning phase of a radial or meshed electrical network in a wind farm.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Neng Fang, Zhengqi Li, Jiaquan Wang, Bin Zhang, Lingyan Zeng, Zhichao Chen, Haopeng Wang, Xiaoying Liu, Xiaoyan Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Removing end surfaces of a multi-channel burner which is the most commonly used burner type in entrained flow gasifiers could ease the risks of burner and cooling screens burning. On an air-particle test facility, experiments were conducted to investigate the influence of the improvements in a 2000 t/d GSP gasifier on the air/particle flow characteristics using a particle dynamics anemometer. For GSP burner and improved GSP burner (IGSP burner), the M-shaped distribution of mean axial velocity appears at the cross-section 〈em〉x/d〈/em〉 = 4 and 6, respectively. By removing the end surface, the air and particles first diffusing to the near-wall region under the IGSP burner is delayed resulting in a lower risk that the cooling screen is burned. In IGSP burner, the central recirculation zone is smaller in both radial and axial directions than in GSP burner; removing the end surface could reduce the risk of burner being burned. Industrial-sized experimental results uncovered that in comparison with the prior GSP burner, the heat absorption of the burner support and the four parallel cooling screens for the IGSP burner decreased by 22% and 53%, respectively, which effectively verified the validity of the structural improvement.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Giovani Dambros Telli, Carlos Roberto Altafini, Josimar Souza Rosa, Carlos Alberto Costa〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The increase in prices and our dependence on fossil fuels coupled with concerns about harmful emissions have motivated researchers to look for renewable and alternative fuels that have clean combustion and which can be produced locally. The fumigation of ethanol in diesel engines has been recognized as an effective alternative to improve efficiency and to reduce emissions. In this paper, the effects of a compression ignition engine using B7 and hydrous ethanol by fumigation method has been investigated. Hydrous ethanol was injected in the engine intake manifold by a port fuel injector, representing ethanol energy ratios from 11.5% to 52.3%. The results indicated a maximum decrease about 69% in smoke index, reduction in exhaust gas temperatures and reduction in both CO and CO〈sub〉2〈/sub〉 emissions. The lowest CO emission found was 0,11% and CO〈sub〉2〈/sub〉 emissions were 4.6% by volume. A maximum increase of 26.2% in thermal efficiency and 22.9% in exergy efficiency was observed. Nevertheless, an increase in HC emissions and specific fuel consumption was noted, achieving the maximum values of 121 ppm and 270.2 g/kWh, respectively. The results were satisfactory, confirming the potential to use ethanol fumigation method to improve thermal and exergy efficiency and reduce harmful gases.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part A〈/p〉 〈p〉Author(s): Azzedine Boutelhig, Salah Hanini, Amar Hadj Arab〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉During the on-site operation, the PV water pumping system can be faced different unexpected troubles, although the accurate sizing and the fit erection. Recently, different studies showed that the lack of enough information about the geospatial characteristics of the area, required during the sizing of a Photovoltaic Water Pumping System (PVWPS) is the main cause. In this attempt, an investigation study on geospatial characteristics has been conducted, in the Mansoura desert region; about 70 km south of Ghardaia headquarter. The main goal was to spotlight on different suitable locations for implementing PVWPS. The study has been carried out on six zones; namely: Ain Losseik, Old Mansoura, New Mansoura, Oued Ghazalat, Khanget-fedj and Zawiat Lacheikh. The evaluation consists on census and classifying the wells or boreholes according to the geographical location, the water source behavior, the soil specifics, agriculture and ranching activity, type of the crops, etc … It has been averred that the renewable aquifer levels vary between the averages of 20 and 45 m. However, the Albian borehole static levels can be reached between the averages of 3 and 8 m. The aquifer hydraulic behavior has been achieved by calculation of hydrogeology properties. Thus, the obtained data were compared and classified, whereas the suitable DC pumps were selected, accordingly. This method can be used to detect the different local geospatial effects influencing the system operation. Furthermore, it can be considered as a key point subject that could be extended, in future works.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Jianlong Wan, Zuwei Xu, Haibo Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A combustor with a plate flame holder and preheating channels, which is expected to take advantage of both heat recirculation and flow recirculation, was manufactured. The laminar premixed flame topology structures were studied experimentally and numerically. Experimental results showed that this special configuration performs excellently in flame-anchoring, and the flame can maintain steadily symmetrical at equivalence ratios as low as 0.425. One ‘U-shaped’ flame root and a constricted ‘waist’ near the middle of the flame front were observed under very small equivalence ratio. A three-dimensional numerical simulation, which was able to reproduce the flame topology structure with high accuracy, was conducted to better understand the flame topology structures. The flame topology structures were analysed quantitatively using multiple transverse and longitudinal sections. The shapes of the flame front near the middle region form ‘S’ patterns, while the ‘C’ style occurs very near the side walls. The flame front at the longitudinal plane near the centre of the combustor is almost straight, but the flame front near the side wall is obviously bending. In addition, the flames near the side wall not only shift downstream but also move towards each other. The above effects can significantly affect the flame topology structures.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Regina Lamedica, Ezio Santini, Alessandro Ruvio, Laura Palagi, Irene Rossetta〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉This paper proposes a methodology that is based on mixed-integer linear programming (MILP) to calculate the optimal sizing of a hybrid wind-photovoltaic power plant in an industrial area. The proposed methodology considers the: i) load requirements; ii) physical and geometric constraints for the renewable plants installation; iii) operating and maintenance costs of both wind and PV power plants; and the iv) electric energy absorbed by the public network.〈/p〉 〈p〉The power demand variation associated with the production cycles is considered by using a stochastic simulation tool. To consider both the load and seasonality variability, and to adapt the methodology to the actual operational use of the power plant, the optimization is performed separately for each month of the year. Then, an integrated economic analysis is discussed. The methodology is adopted to analyze an industrial plant in the Rome area used as a train depot and for maintenance purposes. The results, which combine the needs of the plant activity with the availability of renewable energy, enabled the determination of optimal solutions and the relevant savings achievable.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Valentin Soloiu, Jose D. Moncada, Remi Gaubert, Aliyah Knowles, Gustavo Molina, Marcel Ilie, Spencer Harp, Justin T. Wiley〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Direct Injection of methyl oleate and PFI of n-butanol were used to conduct Reactivity Controlled Compression Ignition (RCCI) and minimize exhaust emissions in reference to conventional diesel combustion. Methyl oleate was investigated for validation of a single fatty acid methyl ester as a surrogate for biodiesel in engine operation. An experimental common rail engine was operated in RCCI and conventional diesel combustion modes under constant boost and similar combustion phasing. The RCCI strategy used two pulses of direct injections with a fixed first injection at 60° before top dead center and a varied second injection for smooth combustion. Ringing intensity was reduced by 70% for methyl oleate RCCI compared to diesel conventional diesel combustion. The molecular oxygen from methyl oleate allowed a reduction in soot by 75% and 25% compared to diesel in RCCI and conventional diesel combustion operation, respectively. Compared to conventional diesel combustion, NOx and soot decreased for RCCI by several orders of magnitude with both emissions approaching near zero levels at low load. The fuels produced a stable RCCI operation where mechanical efficiency was sustained within 2% for same-load points and the coefficient of variation of indicated mean effective pressure was limited to 2.5%.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Yue Chen, Wei Wei, Feng Liu, Miadreza Shafie-khah, Shengwei Mei, João P.S. Catalão〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Co-generation plants have become mainstream energy production facilities at the demand side owing to their high efficiency and flexibility in operation. During the transition to more integrated energy supply, trading of energy mix will become an important issue, where a retailer is expected to play a more active role. This paper discusses the design of retailer's optimal contract with asymmetric information. Bilateral relationship between retailer and consumers can be described as an information game and is characterized by package contracts based on publicly observable information only. First, a mathematical model for the optimal contract design problem involving two coupled energy markets is established. Then, an equivalent reduced model is obtained by several certified lemmas and theorems. Consumer behaviors behind each reduction step are revealed. Thereafter, the market equilibrium is characterized with a proof of existence, revealing the impact of asymmetric information on the retailer's strategy. An illustrative example with locational marginal price based heat-power market is presented. Case studies confirm the theoretical analysis and show that our model can promote retailer's profit. The impact of several factors, such as the probability and reservation utility level, has been tested, providing fundamental insights into strategic behavior in multi-energy market under asymmetric information.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Rongtang Liu, Ming Liu, Peipei Fan, Yongliang Zhao, Junjie Yan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The efficient and clean use of lignite is strategically important to sustainable development. Predrying technology is a competitive approach to solve the utilization issue of the high moisture, and the pyrolysis technology is an ideal upgrading method to realize high value-added components extraction. However, the two technologies are normally used separately. By integrating the two technologies, the cascade utilization of energy may be realized, and the utilization efficiency of lignite may be increased accordingly. Therefore, a steam predrying coupled with lignite-pyrolysis power system (PPPS) is proposed in this paper. Theoretical models are developed on the basis of thermodynamics to assess the properties of the proposed system, and a case analysis is performed to determine the quantitative consequences of the PPPS. Moreover, energy and exergy analyses are performed to uncover the energy saving mechanism. Results indicate that the proposed system can evidently increase the thermal efficiency by approximately 4.43% relatively based on the higher heating value, and by approximately 4.45% relatively based on the lower heating value. The PPPS can noticeably increase the exergy efficiency by approximately 4.48% relatively owing to the integration of the lignite predrying and pyrolysis technologies.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part A〈/p〉 〈p〉Author(s): Giacomo Persico, Alessandro Romei, Vincenzo Dossena, Paolo Gaetani〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper presents the results of the application of a shape-optimization technique to the design of the stator and the rotor of a centrifugal turbine conceived for Organic Rankine Cycle (ORC) applications. Centrifugal turbines have the potential to compete with axial or radial-inflow turbines in a relevant range of applications, and are now receiving scientific as well as industrial recognition. However, the non-conventional character of the centrifugal turbine layout, combined with the typical effects induced by the use of organic fluids, leads to challenging design difficulties. For this reason, the design of optimal blades for centrifugal ORC turbines demands the application of high-fidelity computational tools. In this work, the optimal aerodynamic design is achieved by applying a non-intrusive, gradient-free, CFD-based method implemented in the in-house software FORMA (Fluid-dynamic OptimizeR for turboMachinery Aerofoils), specifically developed for the shape optimization of turbomachinery profiles. FORMA was applied to optimize the shape of the stator and the rotor of a transonic centrifugal turbine stage, which exhibits a significant radial effect, high aerodynamic loading, and severe non-ideal gas effects. The optimization of the single blade rows allows improving considerably the stage performance, with respect to a baseline geometric configuration constructed with classical aerodynamic methods. Furthermore, time-resolved simulations of the coupled stator-rotor configuration shows that the optimization allows to reduce considerably the unsteady stator-rotor interaction and, thus, the aerodynamic forcing acting on the blades.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part A〈/p〉 〈p〉Author(s): Nilesh Purohit, Vishaldeep Sharma, Samer Sawalha, Brian Fricke, Rodrigo Llopis, Mani Sankar Dasgupta〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper analytically investigates and compares the performance of a proposed ‘all-natural’ NH〈sub〉3〈/sub〉/CO〈sub〉2〈/sub〉 cascaded booster system to a conventional R404A direct expansion system as well as to an ‘all-CO〈sub〉2〈/sub〉’ system with multi-ejector unit and flooded evaporator. Performance comparison is made based on the annual combined COP and Life Cycle Climate Performance (LCCP) for operation in selected cities of Middle East and India. Our results show that in extreme warm climate, the energy efficiency of the proposed configuration exceeds that of all-CO〈sub〉2〈/sub〉 configuration by a maximum of about 12.23% and the total emissions are lower by up to 11.20%. However, the all-CO〈sub〉2〈/sub〉 multi ejector system performs better in cold and mild warm climate. In the NH〈sub〉3〈/sub〉/CO〈sub〉2〈/sub〉 cascade, the high temperature NH〈sub〉3〈/sub〉 system can be designed to be isolated from the accessible locations of the supermarket. The work presented is expected to help adoption of natural refrigerants such as CO〈sub〉2〈/sub〉 and NH〈sub〉3〈/sub〉 for commercial application in extreme warm climate conditions prevailing in many cities of Middle East and India.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Fenglei Li, Zhao Chang, Xinchang Li, Qi Tian〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To improve the performance of an air-source heat pump cycle under low ambient temperature, a solar-driven ejector-cascade heat pump cycle which consists of an ejector sub-cycle and a vapor compression sub-cycle is discussed. Energy and exergy models are developed to conduct analyses on the cascade cycle, in which the ejector sub-cycle takes R134a, R1234yf or R141b as a working fluid and the vapor compression sub-cycle uses R1234yf as a refrigerant. The results indicate that the proposed cycle can significantly improve the thermodynamic performance of the air-source heat pump under low ambient temperature, especially when the ejector sub-cycle employs an R141b ejector. Energy investigation finds that the variation of the thermal coefficient of performance (COPh) exhibits the opposite trend to that of the mechanical coefficient of performance (COPm) as the generation temperature, the intermediate condensation/evaporation temperature or the condensation temperature varies. Exergy analysis indicates that the exergy destructions in the solar collector-generator, the ejector, the compressor and the expansion valve of vapor compression sub-cycle are much larger than those in other components. We hence conclude that decreasing various losses in these components are the key tasks to improve the performance and exergy efficiency of the cascade system.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Seyed-Ehsan Razavi, Ali Esmaeel Nezhad, Hani Mavalizadeh, Fatima Raeisi, Abdollah Ahmadi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The paper presents the info-gap theory for the sake of developing a robust framework for short-term hydrothermal scheduling to tackle severe load uncertainty. Deploying this method, the system operator is provided with a robust decision-making strategy to guarantee the minimum cost under load variation condition while practical and technical limitations such as dynamic ramp rate are taken into consideration. For this purpose, the proposed Unit Commitment (UC) problem considering all above advantages would be modeled in a linear framework, which is in turn taken into account as another outstanding feature of this study as it is compatible to apply to real-world systems. In order to investigate the model efficiency, the modified version of the IEEE 118-bus test system having 54 thermal beside 8 hydro plants is chosen as the case study. Eventually, the results demonstrate how demand fluctuations and errors in the predicted load can be tolerated by allocating additional robust cost.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Minghui Hu, Yunxiao Li, Shuxian Li, Chunyun Fu, Datong Qin, Zonghua Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To effectively use and manage lithium-ion batteries and accurately estimate battery states such as state of charge and state of health, battery models with good robustness, accuracy and low-complexity need to be established. So the models can be embedded in microprocessors and provide accurate results in real-time. Firstly, this paper analyzes the electrochemical impedance spectrogram of lithium-ion battery, and adopts impedance elements with fractional order characteristics such as constant phase element and Warburg element to improve the second-order RC integer equivalent circuit model based on the fractional calculus theory. Secondly, a fractional-order equivalent circuit model of lithium-ion battery is established, which can accurately describe the electrochemical processes such as charge transfer reaction, double-layer effect, mass transfer and diffusion of lithium-ion battery. Thirdly, based on the mixed-swarm-based cooperative particle swarm optimization, parameter identification of the fractional-order equivalent circuit model is conducted using the federal city driving schedule experimental data in the time domain. The simulation results show that the model has higher accuracy and better robustness against different driving conditions, different SOC ranges and different temperatures than the second-order RC equivalent circuit model. The SOC estimation accuracy based on the fractional-order equivalent circuit model of lithium-ion battery is validated.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Jorge Igor Apan-Ortiz, Eva Sanchez-Fernández, Abigail González-Díaz〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper aims to evaluate the integration of the steam jet booster in a natural gas combined cycle with CO〈sub〉2〈/sub〉 capture at low part-load operation. The steam ejector takes a high pressure motive steam flows in a supersonic nozzle while dragging a low pressure steam which comes from the crossover. Both flows mix into one at fixed pressure of 3.5 bar and sent to the reboiler. The results are compared with two integration alternatives: uncontrolled and controlled steam extraction control. Uncontrolled steam extraction provides better part-load performance than controlled. However, with sliding pressure, at 42.3% gas turbine load the low pressure steam turbine operates at 27% of its capacity compared with 66% when the energy plant operates without capture, this imposes a potential risk to the integrity of the turbine. When the steam ejector is integrated, there is no significant improvement in the efficiency compared with sliding pressure strategy. However, the used capacity of the low pressure steam turbine increases from 27% to 42.8%. Therefore, the use of the steam ejector represents a solution to avoid severe damage to the low pressure steam turbine, thus bringing more flexibility, and ensure that steam extraction will not impose any constraint to the energy plant with CO〈sub〉2〈/sub〉 capture at part-load.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Ireneusz Szczygiel, Zbigniew Bulinski〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the paper the overview of available technologies for Liquefied Natural Gas regasification is presented. Special emphasis is put on the Prof. Szargut's input to the topic. Both existing and theoretical solutions are shown. Additionally, the zero-order mathematical of on og the technologies is presented.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Takanni Hannaka Abreu Kang, Antônio Marques da Costa Soares Júnior, Adiel Teixeira de Almeida〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Evaluating which electric power generation technologies should comprise the electricity matrix of a country has become a worldwide issue. Multiple factors should be taken into account and issues such as those to do with social, economic and environmental aspects have to be considered in the decision process. In this paper a decision model based on the FITradeoff method is proposed in order to aid multicriteria decision making in the energy planning context. The originality of the paper comes from accommodating, in the proposed model, situations in which the available information is incomplete, when evaluating electric power generation technologies. In order to illustrate the applicability of the model, eight different electrical energy technologies that form the current Brazilian electricity matrix are evaluated under four dimensions: financial, technical, environmental and socio-economic. A sensitivity analysis was performed in order to check the robustness of the results obtained. The application of the proposed model provides information that could be used in Brazil when drawing up energy policies, thus showing the potential use of the method to solve related problems.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Bin Liu, Dedong Wang, Youquan Xu, Chunlu Liu, Mark Luther〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Due to the conflict between economic development and environmental preservation, energy consumption in the construction industry has become an urgent concern. This research aims to measure the interaction between imports and exports in relation to the embodied energy that accompanies international trade from the perspective of vertical specialisation. The energy embodied in the imports and exports of the construction industry is measured and the net embodied energy use is used to identify the level of dependence of the construction industry on international trade. For the construction industries in the selected countries, the share of imported energy embodied in exports is used to show the degree of participation in the global production chain. The construction industries had greater degrees of participation in the international trade of embodied energy from the demand perspective, than from the supply perspective. The findings of this research help to identify the role and position of national construction industries and are beneficial to the design of strategies for the international market. References are also provided to assist policymakers in adjusting natural resource consumption and production structures in the international trade of construction goods and services.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Xin Fu, Xiao-Jun Zeng, Pengpeng Feng, Xiuwen Cai〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The introduction of a new pricing mechanism, the increasing-block tariff (IBT), will not only affect electricity bills for residents, but also lead to a change in residential electricity consumption behaviours. Understanding these consumption patterns will help create more accurate load forecasting and increase the efficiency of the IBT. This study proposes an innovative clustering-based approach for short-term load forecasting under the IBT in China. The new approach initially partitions households into homogeneous groups each of which has distinctive consumption patterns under the IBT, each consumer segment can then select the most appropriate model for load forecasting, and the predicted load demands of different clusters are aggregated to derive the total usage. In particular, the IBT-related attributes are newly introduced into the clustering analysis. The utility and effectiveness of the proposed model is confirmed through a realistic dataset that contains the daily household-level consumption data of 533 households from April 2014 to February 2015. Consequently, the households are classified into five clusters with distinctive consumption patterns, including low-demand and insensitivity to high temperature (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈mrow〉〈mi〉C〈/mi〉〈mi〉l〈/mi〉〈mi〉u〈/mi〉〈mi〉s〈/mi〉〈mi〉t〈/mi〉〈mi〉e〈/mi〉〈msub〉〈mrow〉〈mi〉r〈/mi〉〈/mrow〉〈mrow〉〈mn〉1〈/mn〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉), ordinary users and sensitivity to high temperature (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"〉〈mrow〉〈mi〉C〈/mi〉〈mi〉l〈/mi〉〈mi〉u〈/mi〉〈mi〉s〈/mi〉〈mi〉t〈/mi〉〈mi〉e〈/mi〉〈msub〉〈mrow〉〈mi〉r〈/mi〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉), ordinary users and sensitivity to the IBT (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si3.gif" overflow="scroll"〉〈mrow〉〈mi〉C〈/mi〉〈mi〉l〈/mi〉〈mi〉u〈/mi〉〈mi〉s〈/mi〉〈mi〉t〈/mi〉〈mi〉e〈/mi〉〈msub〉〈mrow〉〈mi〉r〈/mi〉〈/mrow〉〈mrow〉〈mn〉3〈/mn〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉), high-demand consumers and sensitivity to high temperature (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si4.gif" overflow="scroll"〉〈mrow〉〈mi〉C〈/mi〉〈mi〉l〈/mi〉〈mi〉u〈/mi〉〈mi〉s〈/mi〉〈mi〉t〈/mi〉〈mi〉e〈/mi〉〈msub〉〈mrow〉〈mi〉r〈/mi〉〈/mrow〉〈mrow〉〈mn〉4〈/mn〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉), and luxury consumers (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si5.gif" overflow="scroll"〉〈mrow〉〈mi〉C〈/mi〉〈mi〉l〈/mi〉〈mi〉u〈/mi〉〈mi〉s〈/mi〉〈mi〉t〈/mi〉〈mi〉e〈/mi〉〈msub〉〈mrow〉〈mi〉r〈/mi〉〈/mrow〉〈mrow〉〈mn〉5〈/mn〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉). In addition, the obtained experimental results demonstrate that the proposed approach can not only achieve better prediction accuracy (e.g., the mean absolute percentage error (MAPE) improves from 3.82% to 2.28% by using autoregressive integrated moving average (ARIMA)), but also provide better flexibility for hybrid modelling. From the practical implication point of view, the proposed forecasting model can help power companies to provide a reliable and high-quality electricity supply as well as to establish appropriate schedules of operations and maintenance within a certain area. Moreover, the identified consumption behaviours can be analysed and used to improve the design and promote awareness/acceptance of the IBT.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Lara Carvalho, Erik Furusjö, Chunyan Ma, Xiaoyan Ji, Joakim Lundgren, Jonas Hedlund, Mattias Grahn, Olov G.W. Öhrman, Elisabeth Wetterlund〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Previous research has shown that alkali addition has operational advantages in entrained flow biomass gasification and allows for capture of up to 90% of the biomass sulfur in the slag phase. The resultant low-sulfur content syngas can create new possibilities for syngas cleaning processes. The aim was to assess the techno-economic performance of biofuel production via gasification of alkali impregnated biomass using a novel gas cleaning system comprised of (i) entrained flow catalytic gasification with in situ sulfur removal, (ii) further sulfur removal using a zinc bed, (iii) tar removal using a carbon filter, and (iv) CO〈sub〉2〈/sub〉 reduction with zeolite membranes, in comparison to the expensive acid gas removal system (Rectisol technology). The results show that alkali impregnation increases methanol production allowing for selling prices similar to biofuel production from non-impregnated biomass. It was concluded that the methanol production using the novel cleaning system is comparable to the 〈em〉Rectisol〈/em〉 technology in terms of energy efficiency, while showing an economic advantage derived from a methanol selling price reduction of 2–6 €/MWh. The results showed a high level of robustness to changes related to prices and operation. Methanol selling prices could be further reduced by choosing low sulfur content feedstocks.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Naseem Khayum, S. Anbarasu, S. Murugan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Spent tea waste (STW) is an organic waste that is disposed in open land after preparation of tea. Generally, it is disposed in an open land which increases anthropogenic gases. Converting it into useful energy or value added product may reduce disposal problem and anthropogenic activity. In this study, STW was co-digested with cow manure (CM) for obtaining biogas by anaerobic digestion. For this purpose, STW was mixed with CM at different proportions, namely 50:50, 40:60, 30:70, 20:80, and 0:100 percentages on a mass basis, the samples were used in five different anaerobic digesters. The samples were kept in different anaerobic digesters for the study. The effect of important input parameters like pH, Carbon to Nitrogen (C/N) ratio, and digestion time on the biogas production were studied. Further, the collected biogas from the digesters were characterised to ensure the suitability for use as a renewable fuel. Furthermore, the digested slurry was also analysed for its use in agriculture sector. The results are presented in this paper.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Na Sun, Jianzhong Zhou, Lu Chen, Benjun Jia, Muhammad Tayyab, Tian Peng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Accurate and reliable multi-step wind speed forecasting is extremely crucial for the economic and safe operation of power systems. A novel dynamic hybrid model, which combines an adaptive secondary decomposition (ASD), a leave-one-out cross-validation-based regularized extreme learning machine (LRELM) and the backtracking search algorithm (BSA), is proposed to mitigate the practical difficulties of the traditional decomposition-ensemble forecasting models (DEFMs) through adaptive dynamic decomposing and modeling when new data is added. The new ASD method, which fuses ensemble empirical mode decomposition (EEMD), adaptive variational mode decomposition (AVMD) with sample entropy (SE), is developed for smoothing the raw series to reduce computational time as well as enhance generalization and stability of forecasting models. BSA is employed to optimize LRELM to overcome the drawback of instability. To validate its efficacy, the proposed model and thirteen benchmark models are compared by diverse lead-time forecasting of several real cases. Comprehensive comparisons with a coherent set of indices suggest that the proposed model is an effective and powerful tool for short-term wind speed forecasting not only from the perspective of reliability and sharpness but also from the view of overall skills.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360544218319534-egi10DG7KRTWS0.jpg" width="437" alt="Image" title="Image"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Jie Lin, Duc Thuan Bui, Ruzhu Wang, Kian Jon Chua〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The dew point evaporative cooler has been proposed to replace the mechanical vapor compression chiller in air sensible cooling, for its significantly larger energy efficiency and simpler system layout. Many of the existing studies focused on applying a first-law thermodynamic analysis to the dew point evaporative cooler, however, its performance involving the second-law thermodynamic assessment remains unclear. Therefore, in this paper, an exergy analysis of the counter-flow dew point evaporative cooler is conducted. The exergy performance of the dew point evaporative cooling process is examined by incorporating the first law of thermodynamics for energy and mass balances. A counter-flow dew point evaporative cooler prototype has been designed, fabricated and tested to investigate its cooling performance. A 2-D computational fluid dynamics (CFD) model is then formulated to simulate the flow, temperature and humidity fields of the cooler. The model agrees well with the acquired experimental data with the maximum discrepancy of ±5.6%. The exergy flow, efficiency and efficiency ratio of the cooler are discussed under various simulation conditions. Key findings that emerged from this study reveal that the saturated air state at ambient temperature is the rational dead state to properly describe the physical mechanisms involved in the dew point evaporative cooling process. The exergy efficiency ratio of the dew point evaporative cooler is greater than 1.0, highlighting a remarkable second-law efficiency for air conditioning applications.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): R. Stropnik, M. Sekavčnik, A.M. Ferriz, M. Mori〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper an environmental impacts of a 3 kW uninterruptible power supply system with polymer membrane fuel cell (FCH-UPS) was evaluated with a life cycle assessment (LCA) method. The analysis was focused on the analysis of the end of life (EOL) scenarios that will help to reduce environmental impacts during manufacturing stage. Numerical model of the FCH-UPS was developed using Gabi software. The scope of analysis was cradle-to-grave with functional unit 1 kWh of produced electric energy. In operating phase two geographical locations are compared where hydrogen is produced with electrolysis on-site. Three EOL scenarios were analysed: base, feasible and realistic scenario. With realistic EOL scenario in average a 72% reduction of all environmental impacts in the manufacturing phase was achieved. EOL phase of 3 kW FCH-UPS represents low environmental impact compared with other phases in the entire life cycle of observed system. CO〈sub〉2〈/sub〉 emissions of 3 kW FCH-UPS system was 239 g CO〈sub〉2〈/sub〉 per 1 kWh of produced electricity if operating in Norway and 4040 g CO〈sub〉2〈/sub〉 per 1 kWh in Morocco due to electricity grid mix. Results show that with circular economy, recycling and reuse of the materials in EOL phase, an average reduction of 66% in all environmental impact indicators could be achieved in entire life cycle of a 3 kW FCH-UPS system operated in Norway.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Tao Zeng, Caizhi Zhang, Minghui Hu, Yan Chen, Changrong Yuan, Jingrui Chen, Anjian Zhou〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Energy consumption is an important economical index of a fuel cell hybrid vehicle (FCHV). To analyse the energy consumption of a range extender FCHV and reduce the cost of experiments, this study developed a nonlinear regression model of the powertrain of the vehicle to predict the current and voltage on the DC bus, which were used in the investigation of energy consumption, by using the intelligent algorithms including Back Propagation neural network (BP), Genetic Algorithm-Back Propagation neural network (GABP) and least square support vector machine (LSSVM). The model based on the LSSVM achieves the best predicted performance and can consider the nonlinear characteristics of the powertrain quite well. A case study was discussed by applying the obtained model and integrated with a hierarchical energy management strategy (HEMS). The specific results of energy consumption showed that it is feasible to use the predicted data of the obtained model in the analysis of the energy consumption of the FCHV.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part A〈/p〉 〈p〉Author(s): Osman Özkaraca〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Optimizing a complex system/problem under real working conditions with optimization methods means ensuring that they operate more efficiently, economical, and eco-friendly. For this purpose, in order to maximize the exergy efficiency of a thermodynamic model of a real operated geothermal power plant (GPP), two optimization methods, namely Gravitational Search Algorithm (GSA) and Artificial Bee Colony (ABC), have been comparatively evaluated in this study. The selected thermodynamic model is a problem that is highly complex, non-linear and unsolvable through mathematical methods. In order to solve the problem, 17 optimization parameters have been selected on the model. In addition, the selected parameters have been divided into 11 groups according to the system equipment specifications to reduce time loss. The results of the study reported that GSA and ABC maximized the exergy efficiency of the real system from 14.52% to 26.31% and 23.92% respectively. The effects of the optimized parameters on the model are observed, and it has been verified by GPP operators, engineers and researchers that no contrariety to logic and engineering discipline existed. Hence, the results of GSA method for the engineering problem addressed in this study are better than those of ABC method and they responded in a much shorter time. The most effective group in both methods is the G3 group related to the turbines. Besides, the most effective optimization parameters on the system performance are the pressure differences in evaporators and mass flow of the geothermal fluid.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Weiqiang Han, Bolun Li, Suozhu Pan, Yao Lu, Xin Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Reactivity controlled compression ignition (RCCI) is demonstrated as a controllable high efficiency and clean combustion strategy, which is confirmed to be affected by either inlet pressure (IP), total cycle energy (E〈sub〉total〈/sub〉), or start of injection (SOI). This paper discussed their combined effect on low load RCCI combustion and emission characteristics in a multi-cylinder heavy-duty engine fueled with gasoline/diesel. Results show that low temperature heat release (LTHR) only occurs when SOI is sufficiently advanced. Combustion duration (CD) is lengthened, shortened and unchanged with SOI advance under different E〈sub〉total〈/sub〉s, while lengthened with IP increase. NO〈sub〉X〈/sub〉 emission first increases and then decreases with SOI advance, and declines with IP increase or E〈sub〉total〈/sub〉 decrease. Trend CO changes with SOI or IP becomes opposite at the lowest E〈sub〉total〈/sub〉, comparing with that at relatively high E〈sub〉total〈/sub〉s. HC emission decreases with SOI advance or E〈sub〉total〈/sub〉 increase, while it is insensitive to IP. Trend number of nuclear particle (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈mrow〉〈mi〉N〈/mi〉〈mi〉u〈/mi〉〈msub〉〈mi〉m〈/mi〉〈mi〉n〈/mi〉〈/msub〉〈/mrow〉〈/math〉) changes with IP becomes opposite at the highest E〈sub〉total〈/sub〉, comparing with that at relatively low E〈sub〉total〈/sub〉s, while 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈mrow〉〈mi〉N〈/mi〉〈mi〉u〈/mi〉〈msub〉〈mi〉m〈/mi〉〈mi〉n〈/mi〉〈/msub〉〈/mrow〉〈/math〉 decreases with SOI advance or E〈sub〉total〈/sub〉 increase. Both number of aggregated particle (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"〉〈mrow〉〈mi〉N〈/mi〉〈mi〉u〈/mi〉〈msub〉〈mi〉m〈/mi〉〈mi〉a〈/mi〉〈/msub〉〈/mrow〉〈/math〉) and soot first decreases and then increases with SOI advance, and decreases with E〈sub〉total〈/sub〉 decrease or IP increase.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Saeed Salimi Amiri, Shahram Jadid, Hedayat Saboori〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The rapid growth of electric vehicle (EV) penetration is promoted by fossil fuels depletion, environmental concerns, and energy efficiency initiatives. Battery charging time duration is of the main obstacles to large-scale deployment of this technology. Battery swapping station (BSS) is a new concept to handle this issue in which depleted EV batteries are replaced with a previously full-charged one at a significantly less time duration. To this end, the optimum location of the EV charging among BSSs in the network in addition to the priority charging of the depleted batteries in each BSS should be determined. In this context, the present paper is to perform these tasks optimally and simultaneously. The problem is formulated as a multi-objective programming model in which three non-homogenous objectives are taken into account and solved using the NSGA II algorithm. Two cost-based objectives including minimizing EV batteries charging and power loss cost along with two technical based objectives, comprising voltage profile flattening and network capacity releasing, are considered. Additionally, besides dynamic pricing scheme, a time window method to prevent interruptions in the battery charging is developed. The proposed model is implemented on 33-bus IEEE test system where the results demonstrate its functionality.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Guoguang Ma, Hongfang Lu, Guobiao Cui, Kun Huang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Power generation is the most important way to utilize LNG (liquefied natural gas) cold-energy. Currently, the efficiency of LNG cold-energy power generation is low, so it is necessary to improve the process. On the other hand, the requirements of refrigerants for different LNG cold-energy power generation cycles are different. Thus, improper selection of refrigerant can increase exergy loss and decrease the cold-energy utilization. In view of these two aspects, this paper makes a deep research on conventional refrigerants for low-temperature Rankine cycle (RC), the refrigerant selection principle of RC is determined. Based on the study of the LNG cold-energy release law and its gasification characteristics, LNG cold-energy power generation multi-stage utilization model is established. On the basis of the newly established model, the existing process is improved (this paper takes the five-stage RC power generation process as an example). The effects of gasification pressure, seawater temperature and stage number on the system are analyzed. The advantages of the multi-stage Rankine cycle (MSRC) are evaluated from the exergy recovery rate (ERR), LNG cold-energy utilization and net power generation (NPG). The main conclusions can be obtained: (1) compared with the single-stage RC, the ERR, cold-energy utilization, cold-exergy utilization and net power generation (NPG) of the five-stage RC are much higher. (2) under subcritical pressure conditions, the NPG of the first-stage cycle and the second-stage cycle accounts for the majority of the entire system NPG. (3) The difference in NPG between the two stages in the “supercritical pressure” grading system is not significant. (4) As the stage number of MSRC increases, the growth rate of NPG gradually slows down.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part A〈/p〉 〈p〉Author(s): Andrzej Ziębik, Paweł Gładysz〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉The complexity of contemporary energy arrangements created the necessity to apply not only a process approach, but also a system approach in energy and exergy analyses. This distinction was developed at Professor Jan Szargut's Silesian School of Thermal Engineering in the 1960s, and Input-output (I-O) analysis as a method of mathematical modelling of energy systems was applied. The I-O linear mathematical model of the energy economy of an industrial plant was then developed, and the following problems were resolved:〈/p〉 〈p〉- optimisation of the mathematical model in order to select the optimal structure of the energy economy of industrial plants within the framework of preliminary design,〈/p〉 〈p〉- nonlinear mathematical model of the energy management of ironworks for control and scheduling,〈/p〉 〈p〉- system analysis of the exergy losses considering the energy systems of ironworks,〈/p〉 〈p〉- mathematical model of the energy production system of complex buildings, and〈/p〉 〈p〉- application of the I-O model in energy and exergy analyses of oxy-fuel combustion power plants with CO〈sub〉2〈/sub〉 capture, transport, and storage.〈/p〉 〈p〉The I-O method was also applied in the modelling of calculations of the cumulative energy and exergy consumption, cumulative emissions, and the indices of thermo-ecological costs.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Wei You, Yong Geng, Huijuan Dong, Jeffrey Wilson, Hengyu Pan, Rui Wu, Lu Sun, Xi Zhang, Zhiqing Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The expansion of renewable energy sources for electricity generation is an important part of China's energy strategy to reduce the dominance of coal generated power. Different energy systems face unique challenges with their different energy structures and economic context, which make it necessary to identify the roadmap for renewable energy development with consideration of local energy system. Our study aims to fill a research gap by identifying the penetration of renewable energy in China's energy system. The study begins with a brief review of the current state of renewable energies in China and then identifies the effect of large penetration of wind power and solar energy. China's energy system is simulated using the EnergyPLAN model and assessed under different penetration points of renewable energy sources from technical and economic perspectives. Different realistic intervals of penetration are discussed. Finally, our analysis identifies that the maximum realistic penetration of wind power and solar energy are respectively 38% and 27%.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part A〈/p〉 〈p〉Author(s): Victor Onyenkeadi, Suela Kellici, Basudeb Saha〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The synthesis of 1,2-butylene carbonate (BC) from cycloaddition reaction of 1,2-butylene oxide (BO) and carbon dioxide (CO〈sub〉2〈/sub〉) was investigated using several heterogeneous catalysts in the absence of organic solvent. Continuous hydrothermal flow synthesis (CHFS) has been employed as a rapid and cleaner route for the synthesis of a highly efficient graphene-inorganic heterogeneous catalyst, ceria-lanthana-zirconia/graphene nanocomposite, represented as Ce〈img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉La〈img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉Zr/GO. The heterogeneous catalysts have been characterised using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and nitrogen adsorption/desorption (BET for measuring the surface area/pore size distribution). Ceria-lanthana-zirconia/graphene nanocomposite catalyst (Ce〈img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉La〈img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉Zr/GO) exhibited high catalytic activity as compared to other reported heterogeneous catalysts in the absence of any organic solvent with a selectivity of 76% and 64% yield of 1,2-butylene carbonate at the reaction conditions of 408 K, 75 bar in 20 h.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part A〈/p〉 〈p〉Author(s): Rongshan Bi, Chen Chen, Jiansong Li, Xinshun Tan, Shuguang Xiang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Flash boiling atomization (FBA) can achieve the droplets with smaller diameter and more uniform diameter distribution compared with the traditional atomization, which therefore can contribute to accomplishing higher mass and heat transfer efficiency in the gas-liquid ejector. However, the research on the mechanism of FBA was still insufficient, especially that there is not yet a recognized and reliable model which can integrate the factors during FBA process. In this work, FBA model was established based on the traditional primary breakup model, which was then compared with the cited experimental data to verify the reliability of the model. Afterwards, the FBA model was adopted to study the influence of the vaporization ratio, surface tension, density and viscosity of the droplets on the atomization efficiency. The results showed that with the increase in the vaporization ratio and density, smaller droplets with more uniform diameter distribution were obtained; while the increase in the surface tension and viscosity caused the increase in the droplet diameter and discreteness of the diameter distribution.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Pengfei Sheng, Xiaohui Guo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The scale of urbanization in China has more than doubled in the last two decades, with important consequence of transforming the landscape of energy. While the relationship between urbanization and energy use has been examined extensively, the question of whether urbanization affects energy efficiency receives less attention. In this study, we seek to provide new empirical evidence on the effect of urbanization on energy use and efficiency in China. We extend the stochastic frontier approach to model the demand for energy while measuring energy efficiency by distinguishing between efficient- and inefficient-use. Using data from a variety of sources during 2005–2015 to generate an eleven-year province-level panel, we estimate a simultaneous-equation model through a random effects panel data specification. We find that urbanization in China during our sample period is associated with a significant increase in energy consumption, but there is little evidence of improvement in energy efficiency. In particular, our results from our preferred specification suggest that the inefficient-use accounts for approximately 23% of the total energy consumption.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Haozhong Huang, Jizhen Zhu, Delin Lv, Yaopeng Wei, Zhaojun Zhu, Binbin Yu, Yingjie Chen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A reduced 〈em〉n〈/em〉-heptane-〈em〉n〈/em〉-butylbenzene-PAH mechanism consisting of 111 species and 542 reactions was developed for diesel engine combustion and soot modeling. The reduced mechanism was formulated based on a detailed 〈em〉n〈/em〉-butylbenzene (BBZ) mechanism and a published reduced 〈em〉n〈/em〉-heptane-PAH mechanism. The reduced BBZ sub-mechanism was constructed using the directed relation graph with error propagation, sensitivity analysis, reaction pathway analysis and rate of production analysis methods. An evaluation system of the most sensitive reactions was proposed and sensitivity coefficient maps of ignition delay were depicted for the optimization of the proposed mechanism. The present mechanism was extensively validated with experimental results of ignition delay in shock tubes and rapid compression machines, species concentration in premixed flames and jet stirred reactors, laminar flame speed, and with new direct injection compression ignition engine combustion and emission data. The results of prediction are in good agreement with experiments and suggest that the proposed mechanism can be applied for combustion and soot predictions in engines. The soot particle size distribution of BRF30 (30%BBZ+70%〈em〉n〈/em〉-heptane in volume) is closer to D100 (real diesel) than TRF20 (20%toluene+80%〈em〉n〈/em〉-heptane in volume). It is indicated that BBZ may be more appropriate as the representative of aromatic compounds than toluene in diesel surrogate fuels.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part A〈/p〉 〈p〉Author(s): Andrzej Szlek, Wojciech Stanek〈/p〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Deli Zhang, Fang Wang, Xiuli Shen, Weiming Yi, Zhihe Li, Yongjun Li, Chunyan Tian〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, hydrothermal carbonization (HTC) was employed to upgrade the fuel quality of corn stalk digestate (CSD) ranged from 190 to 240 °C. Meanwhile, a comparison of corn stalk (CS) was investigated to explore the effects of anaerobic digestion (AD) on the fuel property and combustion behavior of hydrochars. The results showed that the HTC increased the carbon content and heating value of hydrochars while decreased the alkali and alkaline earth metals (AAEMs) content and hydrophilicity. Compared to CS, the CSD showed higher low-temperature HTC activity, but lower sensitivity to temperature changes. The improvement of fuel properties on CSD was limited with the HTC temperature increasing. The thermogravimetric analysis displayed the relative low temperature HTC (190 and 215 °C) improved the combustion of CSD, while 240 °C was appropriate for CS. FTIR and SEM analyses confirmed the aromatization and formations of spherical particles in CS hydrochars obtained at 240 °C, respectively, but was not observed in CSD hydrochars. The AD process weakened the pyrolysis-like reaction of cellulose in HTC. Considering the energy balance and engineering, 190 °C was recommend for the preparation of solid fuels from CSD and seemed to be more viable for the combination of AD and HTC.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Wei Li, Shubin Gao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Global climate change is a significant environmental problem. A major trigger of climate change is the excess carbon emissions. Based on 44 scenarios in the second generation of new dry cement technology systems, this paper establishes IPSO-BP model to forecast the carbon emissions peak of China‘s cement industry for 2016–2050 years. The results indicate that China's cement industry only implements capacity reduction plans and the second generation of new dry cement technology systems, so that carbon emissions can reach the peak before 2030. It is up to 19 years ahead of the carbon emissions peak of the basic scenario and the carbon emissions peak is reduced by 38 Mt. Moreover, this paper analyzes the technical combination of the earliest carbon emissions and the lowest carbon emissions. As for the earliest carbon emissions technical combination, China's cement industry carbon emissions will peak at 789.95 Mt in 2021. According to the lowest carbon emissions technical combination, China's cement industry carbon emissions will peak at 742.37 Mt in 2025. Accordingly, the conclusions will be helpful for making carbon emissions reduction policies for China's cement industry.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part A〈/p〉 〈p〉Author(s): Ting Yue, Noam Lior〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Past studies on hybrid power cycles using multiple heat sources of different temperatures focused mainly on case studies and almost no general theory about this type of systems was developed. This paper is a study of their general thermodynamic performance, with comparison to their corresponding single temperature heat source reference system, focusing on the Brayton cycles: simple Brayton cycle, and Brayton cycle with intercooling, reheat and heat regeneration. The generalized expressions for the energy and exergy efficiency difference between the hybrid and the corresponding single heat source reference systems were developed, which allow easy determination of the extent of relative desirability of the hybrid systems in that respect. The design and operating conditions under which the hybrid systems become more efficient than the non-hybrid reference ones were found. A number of case studies were simulated (after validation) to help basic understanding and confirm the thermodynamic generalization of the results. One of the results showed that the largest exergy destruction occurs in the combustors (67% to total exergy destruction) and can be reduced by using additional heat sources (AHS) that are of lower temperature difference between the heating and heated streams, and/or renewable energy. The sensitivity analysis results further suggested that efforts should be made to increase the energy conversion efficiency of the AHS. The effects of AHS input and temperature on energy efficiency, fuel depletion and emissions were studied and compared with the conventional Brayton cycles. It was found that addition of the AHS, i.e. cycle hybridization, reduces emissions and fuel depletion and thus has an advantage over conventional non-hybrid Brayton cycles. A thermodynamic foundation of such hybrid systems was laid, and some easy guidance was provided for use in their preliminary design, before their highly time-consuming and expensive detailed analysis, simulation, and experiments.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Diankai Qiu, Linfa Peng, Peng Liang, Peiyun Yi, Xinmin Lai〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Mechanical degradation, caused by local stress concentration and variation, significantly affects the lifetime of proton exchange membrane fuel cells. This study constitutes the first numerical investigation of stress evolution in the membrane between the frame of the membrane exchange assembly (MEA) and gas diffusion layer (GDL) throughout the processes of assembly, operation and gas filling in fuel cells. A finite element model is outlined to determine mechanical deformation of the membrane by exerting assembly displacement, hygrothermal conditions and gas pressure in turn. It is observed that severe stress concentration and bending deformations occur in the joint-area membrane. The results show that a plastic deformation occurs after the temperature and water content are increased, and would be substantially enhanced by the gas pressure difference between the anode and cathode. The in-plane stress may throw some light on the rapid degradation of the membrane between the frame and GDL. The gas pressure difference, which exceeds 10 kPa, leads to a rapid increase in the in-plane stress and plastic deformation. Decreasing the joint width may not be a good approach for reducing the stress/strain concentration. It is suggested that additional gasket seals or adhesive protection layers are helpful in joining frame and GDL.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Subhash Paul, Animesh Dutta, Fantahun Defersha〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this research a hybrid thermochemical and biochemical approach is proposed to produce biocarbon, biomethane and biofertilizer from corn residue using the concept of resource recovery from biowaste. In this approach, corn residue is first pretreated in hydrothermal carbonization process to produce solid biocarbon. Hydrothermal process water, a co-product of hydrothermal carbonization process underwent fast anaerobic digestion to produce biomethane and biofertilizer. Effects of operating conditions (process temperature and residence time) on both biocarbon and hydrothermal process water contents were studied. Four selected hydrothermal temperatures of 200 °C, 220 °C, 240 °C and 260 °C and their three corresponding residence times of 10 min, 20 min and 30 min were considered. Among these 12 hydrothermal processes, 240 °C for 30 min process produced hybrid bioenergy of 14.26 MJkg〈sup〉−1〈/sup〉 of raw corn residue with an overall energy yield of 78.65%. Biocarbon produced at 240 °C for 30 min and 260 °C for 10–30 min were comparable to pulverized coal used in power plants, which contained high heating values of 23.01 MJkg〈sup〉−1〈/sup〉 to 24.70 MJkg〈sup〉−1〈/sup〉. All anaerobic digestion digestate are nutrient enriched and useable as liquid fertilizer.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360544218319558-egi10462PW2ZR7.jpg" width="300" alt="Image" title="Image"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Filomena Ardolino, Concetta Lodato, Thomas F. Astrup, Umberto Arena〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The study provides for the first time a life cycle inventory model for the fluidized bed gasification of wastes, based on a large amount of high-quality data. All of them have been obtained from a pilot scale fluidized bed gasifier, fed with ten types of waste and biomass, under a wide range of operating conditions. The model refers to commercial scale gasifiers having a “thermal configuration”, where the generated syngas is immediately burned downstream of the reactor. Key relationships between process- and waste-specific parameters have been defined. The model quantifies the main inputs and outputs of the gasification process (emissions, energy recovery, ash disposal, resource consumptions), providing high-quality data that could contribute to improve life cycle assessment modelling of waste gasification. Finally, some case studies have been implemented in the EASETECH software to illustrate the model applicability, evaluate the role of main parameters, and compare the environmental performances of gasification power units with that of the European electricity mix. The performances appear highly affected by metal contents in the waste-derived fuels, while the model results to a limited extent are sensitive to the equivalence ratio and the net electrical efficiency of the energy conversion.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): Yuanyuan Zhang, Haohao Sun, Yunfeng Qiu, Enhao Zhang, Tiange Ma, Guang-gang Gao, Changyan Cao, Zhuo Ma, PingAn Hu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Bifunctional electrocatalysts for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is of fundamental significance for efficient solar-water splitting devices. Herein, we report the preparation of CoP nanoparticles embedded in N-doped mesoporous carbon 〈em〉via〈/em〉 a simple yet facile route involving the polymerization of dopamine, Co salts and Si precursor, as well as the subsequent phosphidation treatment. The as-prepared catalysts not only can efficiently catalyze the HER in acidic and basic media with overpotential of 139 and 203 mV to reach current density of 10 mA cm〈sup〉−2〈/sup〉, but also favors the sluggish OER process due to the presence of cobalt oxy-hydroxide on the surface of CoP, showing overpotential of 345 mV to acquire the same current density. The efficient catalytic activities are, highly probably, attributed to the favorable mass-transfer in the nanoporous carbon, interfacial effects at nitrogen dopants enriched site, small charge transfer resistance, as well as synergistic effect between active species and underlying support. The catalysts are appealing to serve as the promising bifunctional electrocatalysts for overall water-splitting with overpotential of 1.72 V to reach current density of 10 mA cm〈sup〉−2〈/sup〉.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S036054421831973X-fx1.jpg" width="293" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy, Volume 165, Part B〈/p〉 〈p〉Author(s): M. Beccali, M. Bonomolo, F. Leccese, D. Lista, G. Salvadori〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Street lighting is an indispensable feature for the night landscape of cities. It is important for road safety, users visual comfort, crime prevention and to augment the perceived personal safety. Realize and maintain an adequate street lighting service is very expensive for municipalities with significant impact on their budgets. For this reason, special attention should be paid to the design of new street lighting systems and to the refurbishment of existing ones, since many of them are inadequate. In light of this it is very important to implement street lighting designs that fulfil lighting requirements avoiding energy waste and light pollution and, at the same time, result economically sustainable for municipalities. In this paper, an original step by step methodology for the lighting, energy and economic analysis of street lighting refurbishment designs has been introduced and explained in detail. The methodology is suitable for use in cities of different sizes. As an applicative example, the methodology has been tested in the town of Pontedera (Italy) and the results are discussed, also providing a sensitivity analysis of the economic feasibility with respect to the variations of electricity prices and investment costs.〈/p〉〈/div〉 〈/div〉