污水源热泵系统运行性能实测与节能潜力分析

Field Measurement and Energy-saving Potential Analysis on the Performance of a Sewage-water Heat Pump System

笔者对大连某原生污水源热泵供热供冷系统进行了实测,获得了该系统供暖季和供冷季的运行数据,供暖季污水温度平均值为10.45℃,机组和系统平均COP分别为5.02和3.93;供冷季污水温度平均值为18.43℃,供冷季机组和系统平均COP分别为6.26和4.54。为了进一步减少污水源热泵系统的运行能耗,提高系统COP,一方面对污水换热器换热系数进行测试研究,与运行初期相比污水换热器换热系数下降了50.08%,更换换热器后,机组和系统COP分别提高了16.08%和11.36%,说明污水源热泵系统定期清洁和更换换热器的重要性;另一方面对污水源热泵机组变工况运行时蒸发器侧和冷凝器侧进水温度和流量对机组性能影响进行分析,基于Data Fit软件建立了机组性能随蒸发器和冷凝器进水温度和流量变化的数学模型,并基于TRNSYS平台对系统负荷侧水泵定频和变频工况分别进行模拟,变频运行机组和系统COP均增加,系统累计能耗减少约18.52%。

A sewage-water heat-pump system( SWHP) for building heating and cooling in Dalian,Liaoning Province,northeastern China,is measured on-site,which is a renewable energy demonstration project. The measurement results show that the average heating coefficient of performance( COP) of a single heat-pump unit and the whole system are 5. 02 and 3. 93,respectively,when the average sewagewater temperature is 10. 45 ℃ during the entire heating season. The average cooling COPs are 6. 26 and 4. 54,respectively,when the average sewage-water temperature is 18. 43 ℃ during the entire cooling season. To improve the system performance,an energy-saving analysis was conducted according to survey data. The test results show that the unit and system COPs increase by 16. 08% and 11. 36%,respectively,as the heat-transfer coefficient of the sewage heat exchanger increases by 50. 08%. Moreover,a SWHP model was established,and the system energy consumption under fixed and variable-frequency water-pump conditions was simulated using the Transient System Simulation Tool( TRNSYS) software. The simulated result shows that the energy consumption of the variable-frequency operation is less than the fixed frequency by 18. 52%.