结霜工况下空气源热泵动态性能衰减特性研究*
摘要：
为了研究不同相对湿度条件下空气源热泵的结霜特征和蒸发器换热能力衰减情况,本文构建了蒸发器动态结霜模型和基于此模型的热泵系统模型,分析了不同相对湿度条件下的蒸发器动态结霜特征和热泵系统性能衰减情况。结果表明:相对湿度越大,结霜速度越快,蒸发压力下降越剧烈,空气侧压降增大速率越大,蒸发器翅片效率下降越快;蒸发器结霜会造成热泵系统性能衰减,空气相对湿度越大,系统性能衰减越严重,在相对湿度90%的条件下,结霜30 min时,系统COP衰减2.69%。
Abstract：
In order to study the frosting characteristics of air-source heat pumps and the heat transfer capacity degradation of evaporators under different relative humidity conditions, this paper constructs a dynamic frosting model of evaporators and a heat pump system model based on this model, and analyses the dynamic frosting characteristics of the evaporator and the performance degradation of the heat pump system under different relative humidity conditions. The results show that the higher the relative humidity, the faster the frosting rate, the more severe the evaporation pressure drop, the greater the increase rate of the pressure drop in the air side, and the faster the evaporator fin efficiency drop. Frosting of the evaporator will cause the performance degradation of the heat pump system. The greater the relative humidity of the air, the more serious the performance degradation of the system. Under the condition of the relative humidity of 90%, the system COP reduces by 2.69% when the frost forms for a duration of 30 minutes.
Keywords:air-source heat pump; frosting; relative humidity; evaporator; performance degradation; coefficient of performance (COP); intelligent defrosting