两级加热热泵系统工作特性研究

Study on the working features of a two-stage heating heat pump system

提出了一种两级加热热泵系统,并详细叙述了其工作原理;该热泵系统在夏季工况下工作时,能够同时生产空调冷热水,而在冬季工况下工作时,采用两级加热的方式生产空调热水;通过建立实验台,进一步研究了冬季工况下热源换热器进出口水温对热泵系统性能的影响,结果发现：当热源换热器进出口水温分别为10/5℃、12/7℃、14/9℃,且热水出口水温在40-55℃之间时,在相同的热源换热器进出口水温和热水出口温度下,当热水进出口温差为10℃时,系统的排气温度、排气压力、压缩机功率都要比5℃温差时的更低,减小的幅度分别为2.01-8.32℃、0.078 1-0.168 7 MPa、3.0%-10.48%;而系统的总制热量、制热COP都要比5℃温差时的更高,增加的幅度分别为0.69%-12.14%、4.66%-18.45%;说明所研究的两级加热热泵系统在大的热水进出口温差下工作时,不仅性能更好,而且也更稳定.

This paper put forward a two-stage heating heat pump system and described its working principle in detail. In the summer, the system can produce hot and cold water for heating and cooling simultaneously. The system can also produce hot water for heating in winter. An experiment station was established for further studying the effects of the inlet and outlet water of the heat exchanger in heat source side on the performance of the heat pump system in winter. The results indicated that： when the temperature of the inlet and outlet water of the heat exchanger in heat source side are respectively 10/5 ℃, 12/7 ℃ and 14/9 ℃, and the temperature of the outlet hot water of the hot heater is between 40 ℃ to 55 ℃, under the conditions of the same temperature of the inlet and outlet water of the heat exchanger and the same temperature of the outlet hot water of the hot heater, the exhaust temperature and pressure of the system and the compressor power with the temperature difference of hot water 10 ℃ are lower than these with the temperature difference of hot water 5 ℃. And the rates decrease respectively 2.01-8.32 ℃,0.078 1-0.168 7 MPa and 3.0%-10.48%. At the same time, the total heating capacity and heating COP of the system with the temperature difference of hot water 10 ℃ are higher than those with the temperature difference of hot water 5 ℃. And the rates increase respectively 0.69%-12.14% and 4.66%- 18.45%.These results showed that the two-stage heating heat pump system working in the condition of big temperature difference of hot water has better and steadier performance.