大多数空气源热泵使用反向cyc/e除霜，以消除正常冬季运行期间室外热交换器上形成的霜。除霜期间，热泵从加热模式切换到除霜模式，向室外热交换器提供热量，以融化霜。一旦霜融化，装置将切换回加热模式。本研究的目的是描述空气源热泵在逆循环除霜过程中的动态响应。对相关设备进行了综述，搭建了实验装置，并进行了实验。试验装置包含一台标称容量为3吨的住宅用空对空热泵，该热泵在除霜期间使用热膨胀阀（TXV）进行膨胀。测量整个系统的制冷剂温度和压力、制冷剂流量、空气侧容量、压缩机/室外风扇功率以及蓄能器中的制冷剂液位。 本文详细描述了除霜期间发生的物理过程。引用:研讨会，ASHRAE Trans。，第95卷，第。2.

Most air-source heat pumps uti/ize the reverse cyc/e defrost to eliminate frost that forms on the outdoor heat exchanger during normal winter operations. During the defrost, the heat pump is switched from the heating to the defrost mode to provide heat to the outdoor heat exchanger to melt the frost. Once the frost is melted, the unit is switched back to the heating mode.The objective of this research was to characterize the dynamic response of an air-source heat pump during the reverse cycle defrost. Relevant fiterature was reviewed, an experimental apparatus was constructed, and experiments performed. The test setup contained a nominal 3-ton capacity residential air-to-air heatpump that used a thermal expansion valve (TXV) for expansion during the defrost. Measurements made of refrigerant temperature and pressure throughout the system, refrigerant flow rates, air-side capacity, compressor/ outdoor fan power, and refrigerant level in the accumulator. A detailed description of the physical processes that occur during a defrost are provided.