ALBERT

Description: Convective mass transport is the transport of mass from near the surface up to the upper troposphere and lower stratosphere (UTLS) by a deep convective updraft. This transport can alter the chemical makeup and water vapor balance of the UTLS, which affects cloud formation and the radiative properties of the atmosphere. It is, therefore, important to understand the exact altitudes at which mass is detrained from convection. The purpose of this study was to improve upon previously published methodologies for estimating the level of maximum detrainment (LMD) within convection using data from a single ground-based radar. Four methods were used to identify the LMD and validated against dual-Doppler-derived vertical mass divergence fields for six cases with a variety of storm types. The best method for locating the LMD was determined to be the method that used a reflectivity texture technique to determine convective cores and a multilayer echo identification to determine anvil locations. Although an improvement over previously published methods, the new methodology still produced unreliable results in certain regimes. The methodology worked best when applied to mature updrafts, as the anvil needs time to grow to a detectable size. Thus, radar reflectivity is found to be valuable in estimating the LMD, but storm maturity must also be considered for best results.

Description: Several months of regional convection-permitting forecasts using two microphysical schemes (WSM6 and Thompson) are evaluated to determine the accuracy of the simulated convective structure and convective depth and the impact of microphysical scheme on simulated convective properties and biases. Forecasts are evaluated by using concepts from object-based approaches to compare the three-dimensional simulated reflectivity field with the reflectivity field as observed by radar. Results from analysis of both schemes reveals that forecasts generally perform well near the surface but differ considerably aloft both from observations and from each other. Forecasts are found to contain too many convective cores that are individually larger than in the observations, with at least double the number of observed convective cores reaching the midtroposphere (i.e., 4–8 km). Although the number of cores is overpredicted, WSM6 cores typically contain lower simulated reflectivity values than the observations, and the regions of highest reflectivity values do not extend far enough vertically. Conversely, Thompson cores are found to have significantly higher reflectivity values within cores, with the strongest intensities extending higher than in the observations and having magnitudes higher than any observed cores. Forecast reflectivity distributions within convective cells are found to contain more spread than in the observations. The study also assessed the uncertainty in simulated reflectivity calculations by using a second commonly utilized method to calculate simulated reflectivity. The sensitivity analysis reveals that the primary conclusions with each method are similar but the variability generated by using different simulated reflectivity calculations can be as pronounced as when using different microphysical schemes.

Description: The growing interest in the use of unconventional energy sources is a stimulus for the development of dedicated devices and technologies. Drain water heat recovery (DWHR) units can be an example of such devices. They allow the recovery of part of the heat energy deposited in grey water. This paper describes the results of research on the assessment of the financial profitability of the use of two horizontal heat exchanger solutions, taking into account the actual distribution of cold water temperature during the operating year in the plumbing and two operating regimes of the premises as the residential and service facilities. The analysis showed that the use of a horizontal heat exchanger with increased efficiency in a dwelling in a 15-year life cycle allowed for achieving more than twice as much savings (reaching up to EUR 1427) compared to a classic horizontal heat exchanger. At the same time, it was shown that the installation of this type of equipment was more profitable the greater the water consumption of the premises. The article also notes the impact of cold water temperature in the installation on the results of the analysis. It was featured that taking temperature on the basis of installation design recommendations led to significant distortions in the financial analysis. On the other hand, comparing the method of averaging the cold water temperature (daily, monthly and yearly), it was determined that averaging the temperature over the annual cycle was an acceptable simplification of the model. The research results presented in the paper have a practical aspect and may constitute guidelines for designers and potential investors. In addition, they can be an incentive to continue research on heat exchangers by other scientific centers, which on a global scale will increase the universality of their use.

Description: To determine the effectiveness of the retention capacity utilization of traditional and innovative drainage systems equipped with damming partitions, the detailed model tests were carried out. The research results allowed indicating what values of the hydraulic parameter of the innovative drainage system should be adopted in order to effectively use the retention capacity of drainage collectors. The adoption of short distances between the LKR damming partitions and a high level of permissible rainfall of stormwater Hper turned out to be the most effective solution. In the most favorable conditions, the peak flow was reduced by up to 60% (717.46 dm3/s) compared to the values established in the traditional drainage system (1807.62 dm3/s). The benefits obtained resulted from the increased retention efficiency of the drainage system after equipping it with the damming partitions. It was found that the innovative system always achieved the maximum retention capacity with longer rainfall compared to the traditional system. In the real catchment area, an increase in the use of the retention capacity of the drainage system, from an initial value of 65% for a traditional system to almost 88% for an innovative system, was also found. Very large variability of the volume of accumulated stormwater in the conduits of the traditional and innovative drainage system was observed during rainfall, which generated the peak rainfall discharge in the innovative system. With rainfall of TRK duration, the innovative system accumulated up to 746.50 m3 more stormwater compared to a traditional system, which was 49.2% of the total retention capacity of the drainage system, with a value of 1515.76 m3. The approach to reduce the growing flood risk in cities provided the right approach to long-term urban drainage system planning, especially since traditional drainage systems are still the leading way to transport stormwater in cities. In addition, the innovative sewage system gives the possibility of favorable cooperation with any objects (LID) and retention tanks with any hydraulic model. The implementation of an innovative system allows achieving significant financial savings and reducing the need to reserve areas designated for infrastructure investments.

Description: Stormwater is a valuable resource, whose management in harmony with nature is one of the main challenges of modern water management. The problems encountered are additionally exacerbated by the lack of space for the development of sustainable drainage systems. For that reason, new housing estates should be designed considering efficient stormwater management. This paper assesses five stormwater management models to determine the statistically most appropriate model for managing stormwater in newly designed multi-family housing estates using multi-criteria analysis. Various options were assessed by means of the scoring method based on six groups of criteria (political, economic, social, technological, legal, and environmental). The research considered the different views and priorities of the experts involved in stormwater management in Poland. A survey conducted among them showed that the statistically most suitable way of managing stormwater is its infiltration into the ground with the use of infiltration basins or tanks. Only if the possibility of their application is excluded, should the application of other models of stormwater management, especially its retention, be considered. It is expected that the research results presented in this paper will be a guide for investors and developers, and their use will allow people who are not experts in the field of stormwater management to make appropriate decisions.

Description: In recent years an increase of interest in usage of renewable energy sources as a substitution of fossil fuels is being noticeable. However, the waste heat potential, which can be used as an additional source of energy for heating water in buildings, is being omitted. The sources of this heat can be grey water discharged from such sanitary facilities as showers or washing machines. In response to this issue, we took on the task to define and analyze key factors affecting the development of DWHR (Drain Water Heat Recovery) systems using PESTLE (political, economic, social, technological, legal and environmental) analysis. The strengths and weaknesses of these systems were also identified. The studies were based on CFD (computational fluid dynamics) modeling tools. In the Autodesk Simulation CFD software environment, a DWHR unit was made, which was then analyzed for heat exchange efficiency. The obtained results were the basis for preparing the strategy for the development of Drain Water Heat Recovery systems. It was made using the SWOT/TOWS (strengths, weaknesses, opportunities and threats/threats, opportunities, weaknesses and strengths) method, which precisely orders information and allows presenting the project characteristic in readable way for a recipient. The results of the conducted analysis indicated the lack of acceptance on the part of potential users and the resulting need to promote the use of Drain Water Heat Recovery systems at residential level.

Description: This article is aimed at defining the impact of the direction and velocity of waves of rainfall as they pass over interconnected stormwater detention tank systems. The simulations were conducted for a real urban catchment area as part of the Storm Water Management Model (SWMM) 5.1 programme. The results permit us to conclude that the direction and velocity of a moving wave of rainfall have a significant influence on the required volumes of interconnected stormwater detention tank systems. By comparing the modelling test results for stationary rainfall and rainfall moving over the urban catchment area, it has been demonstrated that differences in the required volume of the detention tank located at the terminal section of a stormwater drainage system are inversely proportional to the adopted value of the diameter of the outfall channel for upstream storage reservoirs. In extreme cases, the differences may be up to several dozen percentage points. Furthermore, it has been proven that the arrangement of the stormwater detention tanks in relation to one another and the adopted diameter of the outfall channel are key factors in identifying the degree to which the detention tanks are hydraulically dependent on one another.

Description: In order to identify the most effective variants for reducing flood risk in cities and to provide protection for water resources, an in-depth study was carried out. The research results allowed for the identification of sustainable drainage infrastructure solutions that should be used to increase the efficiency of traditional drainage systems. The most effective solution turned out to be the simultaneous use of low impact development facilities and stormwater flow control devices in drainage systems (Variant IV). Applicationof this variant (maximum discharge QOmax = 246.39 dm3/s) allowed for the reduction of the peak flow by as much as 86% in relation to those values that were established in the traditional drainage system (maximum discharge QOmax = 1807.62 dm3/s). The use of Variant IV allowed for a combination of the advantages of low impact development (LID) facilities and stormwater flow control devices in drainage systems while limiting their disadvantages. In practice, the flow of rainwater from the catchment area to the drainage system was limited, the share of green areas increased, and the drainage system retention capacity grew. The proposed approach for reducing the increasing flood risk in cities and providing protection for water resources provides a structured approach to long-term urban drainage system planning and land use guidelines.