4E analysis of thermal recovery potential of industrial wastewater in heat pumps: An invisible energy resource from the iranian casting industry sector

Abstract

Heat pumps are technologies that use renewable energy and are also environment-friendly and therefore used in different countries. Due to the thermal potential of industrial wastewater they can be used as a suitable source in heat pumps. This study compares the energy, exergy, economic and environmental aspects of an industrial wastewater heat pump (WSHP) with air source heat pump (ASHP) and geothermal heat pump (GSHP) systems in the city of Mashhad. The results showed that the coefficient of performance (COP) and exergy efficiency of the cycle WSHP were 5.104 and 0.3249, respectively, which were higher than the GSHP and ASHP cycles. Using economic analysis, it was found that the higher initial cycle price and lower power consumption of WSHP than ASHP, WSHP made it more economical after 2 years. According to environmental analysis, the use of WSHP reduced CO2 emissions compared to GSHP and ASHP by 15.67 ton/year and 42.2 ton/year, respectively. Also, a comprehensive study was conducted on casting factories in Iran for the use of the WSHP system. The results showed that the amount of heat recovered from casting factories in Iran was about 41 GWh/year. Considering COP of WSHP cycle during the operational condition is 5.104, this cycle can produce thermal energy about 11.8 MW/year, which is used in the field of air conditioning.