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Indexed by:会议论文

Date of Publication:2017-01-01

Included Journals:EI、CPCI-S

Volume:205

Page Number:1769-1776

Key Words:Large temperature difference; heat pump hot water unit; two stage series

Abstract:Generally, the temperature of domestic waste water is high above 30 degrees C. However, when dealt with by common sewage-source heat pump system, temperature difference between inlet side and outlet side is small as 5 degrees C. It leads to manifold cycles and energy waste. To acquire a unit of heat pump water heater of sewage dealing with large temperature difference with high energy utilization rate, through which the cold water (about 5 degrees C) can be heated once to hot water (about 45 degrees C) to reach the temperature for daily use and waste water (about 30 degrees C) can be rapidly dropped to cold water (about 6 degrees C) to satisfy the standard of waste water emissions. In this paper, two staged series of heat pump water heater dealing with large temperature difference is proposed. And performance factor of system is analyzed through simulation by MATLAB so as to find the optimum middle operating point. This method ensures pattern operating in large temperature difference but in small flow at both the hot and cold sides. At the same time, it avoids the lasting elevation of condensing temperature and the constant reduction of temperature in evaporation, which helps to facilitate the stability and optimal performance of the operating unit. (c) 2017 The Authors. Published by Elsevier Ltd.