复叠式空气源热泵热水器结霜工况下的机组运行参数研究

The Study of the Performance Parameters of the Cascade Type Air-source Heat Pump Water on the Frosting Conditions

复叠式空气源热泵热水器可以在冬季低温(-25℃)下最高提供80℃热水,但是机组结霜问题对机组的效率和供热性能影响较大。通过研究复叠式热泵热水器的结霜规律以及结霜对机组性能的影响,为进一步研究并优化除霜控制方法提供依据。系统分为低温级循环和高温级循环,低温级循环为室外系统,高温级循环及蒸发冷凝器部分为室内系统,热泵循环低温级采用R410A作为循环工质,高温级采用R134a,热泵系统高温级冷凝温度为80℃,低温级的蒸发温度可达-40℃。通过在焓差实验室实验进行研究。测试复叠式热泵的结霜过程时间与结霜量,得到不同室外温湿度与结霜量之间的关系。结霜量通过测量低温级蒸发器进出口含湿量的方法获得,并分析结霜对于机组实际耗电量以及COP等性能参数的影响。

The cascade type air-source heat pump water heater can achieve the goal of the production of 80℃ hot water under the ultralow temperature environment （-25℃）, but frosting will influence of the system＇s efficiency and energy consumption. This study focused on the frosting quantity at different outdoor air temperature and the false defrosting probability under various operating parameters. The system consists of a low temperature level cycle and a high temperature level cycle. In the low temperature level cycle, R410A is used as the refrigerant, while in the high temperature level cycle R134A is used as the refrigerant. The experiment was carried out in the enthalpy-difference lab. The time of reaching a certain frosting amount will be obtained, and frosting quantity under different outdoor temperature and humidity were also tested. Moreover, the frosting amount was obtained from the different of the moisture content of inlet and outlet through the evaporator. Then, we will analyze that how the frosting affects the performance parameters of the unit actual power consumption and COP.