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Indexed by:期刊论文

Date of Publication:2021-01-10

Journal:JOURNAL OF BUILDING ENGINEERING

Volume:32

ISSN No.:2352-7102

Key Words:Shower greywater; Serially cascaded wastewater source heat pump; Large temperature difference; Heating performance; Experimental study

Abstract:In order to maximize the recovery of heat energy from shower greywater, improve the operation stability of the wastewater source heat pumps and reduce the complexity of the system, a serially cascaded wastewater source heat pumps (SCWSHP) with large temperature difference was proposed. In this paper, an experimental system for testing the heating performance of the SCWSHP was built. The heating performance of the SCWSHP was analyzed under various operating conditions. And the operating conditions of the SCWSHP were discussed in order to realize that the amount of hot water heated by the SCWSHP is greater than the amount of greywater recovered. The results showed that when the greywater inlet temperature and out temperature are 30 degrees C and 6 degrees C, respectively, the outlet temperature of hot water can be heated to 50 degrees C if tc,i is 15 degrees C. But the maximum outlet temperature of hot water can only reach 41 degrees C if tc,i is 9 degrees C in order to guarantee the operation demand of the system. For the lower tap water inlet temperature, the shower greywater inlet temperature must be increased in order that the hot water outlet temperature can reach 45 degrees C. If t(e,i) is 6 degrees C, the greywater inlet temperature should be improved to 35 degrees C. As long as the outlet temperature of hot water meets the operation requirements, the hot water flow rate should be increased as much as possible, but the flow rate of greywater should be consistent with that of hot water. The results can provide key references for design and operation of the SCWSHP system.