Traditional water heating and cooling methods consume a significant amount of energy. Heating and cooling were also significant contributors to CO2 emissions. Based on several previous studies, heat pumps are an economical solution because they reduce the energy consumed for water heating and the carbon dioxide emissions compared to conventional electric resistant water heaters, gas boilers, and so on. As a result, this chapter presented research studies on waste heat recovery from heat pumps’ immersed helical condenser coils for domestic hot water production. In this work, the three-dimensional geometry of the storage tank with immersed helical pipe heat exchanger was simplified to two-dimensional axisymmetric geometry and the numerical investigation was conducted with using computational fluid dynamics (CFD) commercial software. The variable heat flux from the condenser coil was considered to heat the water in the tank under laminar flow regime. The proposed model was validated with the experimental data and agreed very well. According to the obtained results, the outlet heat flux tended to the decrease with an increase of the heating time. Also, the outcomes indicate that the waste heat can be used for water heating utilized for bathing and cleaning without affecting the heat pumps cycle.
Part of the book: Recent Updates in HVAC Systems