Heat exchanger utilizations in wastewater heat recovery for buildings: A key review

Abstract

The buildings contribute largely to emissions of greenhouse gases. By bringing about changes in this sector, we can achieve significant reductions in these emissions, with an important role in achieving the EU objectives on Near Zero Energy Building (NZEB). According to the European Council, the energy consumption of buildings represents 40% of total energy consumption, contributes to 36% of the emission of greenhouse gases. Worldwide population growth, especially in urban areas, causes an increased consumption of energy and water, especially hot water. Therefore the amount of wastewater discharged is increasing. Wastewater heat recovery units are becoming large utilization of worldwide to reduce energy consumption. A sustainable application in hot water preparation and heating processes for buildings is recovery the energy from wastewater through various heat exchangers. This study provides a comprehensive presentation of wastewater heat exchangers in wastewater source applications. The wastewater heat exchangers are presented based on multiple aspects including the wastewater source, construction methodology, advantages and disadvantages, examples of utilization. In Romanian, approximately 90% of the total volume of wastewater ends up in the sewage system at a relatively high temperature, which later drops upon arrival at a wastewater treatment plant. The implementation of circular economy in as many areas of activity as possible also includes the revaluation of energy from urban wastewater.