Limited availability of fossil fuels and various issues connected with environment conservation lead to a growing interest in unconventional sources of energy. The latter include wastewater carried ...via sewage systems. Yet, the possibility to extract thermal energy from this source depends on a number of factors, location of heat recovery system being one of them. Viability of utilizing raw wastewater and effluent discharged to a receiving body after treatment process, as potential sources of energy, was assessed using SWOT/TOWS analysis. Strategies for developing systems of heat recovery from both types of wastewater have been defined, and recommendations related to their use in Poland have been formulated.
Land cover changes may cause a disturbance in the water cycle, the consequence of which is an increase in the volume of stormwater runoff. In such a situation, the use of traditional stormwater ...systems leads to a number of problems, including the hydraulic overload of these systems and the deterioration of rivers. Therefore, stormwater management clearly affects the quality of life in a particular area. In order to facilitate effective stormwater management, the paper identifies and assesses factors that impact the sustainability of stormwater systems. Using the premises of PESTLE analysis, these factors were categorized as Political, Economic, Social, Technological, Legal, or Environmental. Assessments from an expert team were also used to identify elements that are crucial for the development of innovative solutions for stormwater management.
The recovery of heat from greywater is one of the methods for reducing the energy demand on buildings. The process may be accomplished, e.g. using a Drain Water Heat Recovery (DHWR) unit installed at ...the shower drain. The paper analyzes the rationale for a DWHR unit being installed within a joint drain system of two separate shower installations. To this end, Net Present Values (NPV) and Profitability Indexes (PI) were calculated for the different parameters of a building shower operation. The study showed that the profitability of such investment depends not only on the installation's operation parameters but also on the type of energy carrier.
Wastewater has significant potential as a source of clean energy. This energy can be used both within external sewer networks and on the scale of individual residential buildings, and the use of ...shower heat exchangers appears to be the most reasonable solution. However, in the case of Poland, the problem is still the unwillingness of society to use this type of solution, caused mainly by the lack of space for the installation of vertical drain water heat recovery (DWHR) units and the low efficiency of horizontal units. In response to this issue, the efficiency of a new compact shower heat exchanger designed to be mounted below the shower tray, as well as its linear counterpart, was investigated under various operating conditions. In addition, the financial efficiency of using the compact DWHR unit with average water consumption for showering was evaluated. For this purpose, discount methods were used to estimate the financial efficiency of investments. The study showed that the compact shower heat exchanger has higher efficiency than its linear counterpart. Depending on the temperature of cold water and the flow rate of both media through the heat exchanger, it achieves efficiencies ranging from 22.43% to 31.82%, while the efficiency of the linear DWHR unit did not exceed 23.03% in the study. The financial analysis showed that its use is particularly beneficial when the building uses an electric hot water heater. The investment’s sensitivity to changes in the independent variables is small in this case, even with low water consumption per shower. The only exceptions are investment outlays. Therefore, the compact DWHR unit is a clean energy device, which in many cases is financially viable.
The increase in energy demand, the scarcity of resources, as well as the adverse environmental impact of burning fossil fuels make it necessary to diversify the energy sources used. This also applies ...to the residential sector, which accounts for a significant proportion of global energy consumption. Particular attention should be paid to water heating, as the importance of this process in the energy balance of buildings is steadily increasing. One of the methods used to decrease energy consumption for heating water is to recover heat from greywater. However, commercially available horizontal drain water heat recovery (DWHR) units are characterized by low effectiveness, which creates a need for further research to improve it. The aim of the paper was to evaluate the possibility of improving the effectiveness of a circular horizontal DWHR unit through the use of baffles. Six different baffle models for installation in the greywater section of the heat exchanger were analyzed. The tests were conducted under the assumption of the installation of the DWHR unit on the horizontal shower waste pipe. They showed that the effectiveness of the unit equipped with baffles was higher by several to as much as 40% compared to the DWHR unit without baffles. This is tantamount to an increase in annual financial savings resulting from greywater heat recovery, as well as a reduction in CO2 emissions into the atmosphere. However, it was not possible to clearly identify the optimum baffle model. In any case, the selection should consider the hydraulic conditions in the heat exchanger before installing the baffles. The results can provide guidance for companies interested in bringing new equipment and technologies to the market.
Progressing urbanisation is one of the key causes of environmental degradation. This problem also applies to stormwater management. For this reason, drainage infrastructures should be designed in ...harmony with nature and the decision for selecting a specific stormwater management system solution must not be taken on an ad-hoc or single-perspective basis. The purpose of this paper is to identify the criteria for selecting the best solution for a problem involving the selection of a stormwater management system, and to present a method that will enable all relevant criteria to be taken into account in the decision-making process. The developed decision problem structure takes into account all criteria related to the construction and operation of stormwater infrastructure, and its individual elements were identified based on the analysis and synthesis of information regarding the principles of stormwater management in Poland. The presented approach will allow for the taking into account of all, often mutually exclusive, criteria determining the choice of the stormwater management system option. This, in turn, will make it possible to significantly simplify the decision-making process. The indicated criteria can form the basis for choosing the most favorable stormwater management system for both large urban catchments and individual facilities. Thanks to the considerable flexibility of the developed decision problem structure, its widespread application can contribute to improving the efficiency of stormwater management systems. An example of the developed model’s application in a decision-making process is presented, concerning the selection of a design variant of a single-family residential building’s stormwater management system in Poland. Four design variants were included in the analysis, and the Analytic Hierarchy Process was used as the tool to select the most favorable option. This study shows that nature-based solutions are the most beneficial decision stormwater management options.
The application of infiltration basins and tanks is one of the primary means of sustainable stormwater management. However, the methods currently used to size these facilities do not take into ...account a number of parameters that have a significant impact on their required capacity. In light of this, the aim of this research was to develop a new method for selecting the geometry of the infiltration basins and tanks. Its application in the initial phase of designing stormwater management systems will allow assessing the validity of using such facilities in a given catchment area. This paper also presents the results of local and global sensitivity analyses examining how changes in individual design parameters influence stormwater infiltration facilities. The effectiveness of the developed model was evaluated through the example of a real urban catchment. The study was based on a hydrodynamic analysis of more than 3000 model catchments. The research plan was developed using Statistica software. On the other hand, the analysis of the results of hydrodynamic simulations was made possible through the use of artificial neural networks designed using the Python programming language. The research also confirmed that parameters such as the total catchment area, the percent of impervious area, and the type of soil within the catchment are crucial in the design process of these facilities. The results of this research can be considered when designing infiltration basins and tanks under Polish conditions. The described algorithm can also be used by other researchers to develop similar models based on different rainfall data. This will contribute to increasing the safety of urban infrastructure.
In Poland, domestic hot water is heated mainly using fossil fuel energy sources. Such an approach results in the depletion of natural resources, pollution of the atmosphere and, consequently, ...irreversible changes to the climate. In response to this problem, this research identified the factors that most determine energy savings for heating water in residential buildings, as well as those that affect the choice of an alternative energy source. Additionally, the possibility of implementing shower heat exchangers in existing and newly built residential buildings was assessed, as well as society’s willingness to use such devices. The research was carried out on a sample of 462 inhabitants of the Podkarpackie Voivodeship (Poland). A questionnaire survey was used as a tool. The conducted research has shown that the perspective of environmental protection is not a sufficient motivator to save energy for heating domestic hot water. It is necessary to implement appropriate programs aimed at informing the public about the possibilities offered by the use of alternative energy sources and co-financing the purchase of appropriate devices. In the case of drain water heat recovery systems, a significant problem is also the need to develop new, highly effective designs of shower heat exchangers which can be installed under the floor linear shower drain or on the horizontal shower waste pipe.
The use of greywater reduces the consumption of many resources and is an effective tool for achieving Sustainable Development Goals. In order to assess the rationality of its use as an alternative ...source of energy and water in buildings, a holistic literature review was carried out based on a bibliometric analysis of publications in these fields. The main bibliographic source was the Web of Science database. This review contributed to a better understanding of the analyzed research field. It also revealed trends in greywater energy recovery and recycling research, indicating that these are developing fields. In recent years, there has been a marked increase in the number of publications on the most popular ways of using greywater in buildings, with the territorial scope of research carried out in the greywater recycling domain being considerably larger than research on greywater energy recovery. The analysis revealed poor cooperation between different universities, especially in the field of greywater energy recovery. In light of previous literature reviews, some important research gaps and further proposals for future research were also identified. They concern, in particular, the simultaneous use of greywater as an alternative source of energy and water. Together with the findings of other researchers and people related to the subject matter, this review can contribute to the further development of greywater energy recovery systems and greywater recycling systems.
The potential for recovering heat from wastewater exists at various stages, including generation, transport, and treatment. As a result, various technologies for thermal energy recovery from ...wastewater are now successfully employed in many countries. In order to synthetically present the current state of knowledge on heat recovery from wastewater, a bibliometric analysis of previously published studies indexed in the Web of Science database was performed. The review was further extended with strategic SWOT and SOAR analyses to identify internal and external factors determining the competitive advantage and weaknesses related to the use of wastewater heat exchangers and heat pumps. These analyses indicated the need for further research on the possibilities of heat recovery from wastewater as the use of this technology, both at the building level and on a larger scale, contributes to the implementation of sustainable development goals, especially in terms of improving energy efficiency and reducing CO2 emissions. Particular emphasis should be placed on research into the use of warm wastewater together with other, better known and accepted, renewable energy sources. It is also important to continuously educate the public and promote heat recovery technologies at various levels, as well as to increase the involvement of legislators and other stakeholders.
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