本文从破坏空气源热泵室外机结霜条件出发，概述了空气源热泵无霜化的方法，分别介绍了提高空气温度来实现空气源热泵无霜化的方法、改变空气湿度来实现空气源热泵无霜化的方法和通过其他方法实现空气源热泵无霜化的方法，其中改变空气温度的方法是通过电加热，改变空气湿度的方法又分为固体除湿剂除湿和溶液除湿剂除湿两类，其他的方法为基于热源塔的空气源热泵无霜化和喷淋溶液的空气源热泵无霜化。最后对空气源热泵无霜化的研究方向进行展望：带有余热回收利用的空气源热泵系统可以利用余热或者太阳能来提高流经室外换热器空气温度来实现无霜化；加大对固体除湿剂在低温环境下吸附能力和再生能力研究；重点研究除湿溶液的再生方法以及再生能量来源和再生后水蒸气利用；进一步筛选除湿溶液和防冻溶液。

This paper summarizes the methods for preparation of air source heat pump frost-free from the damage of air source heat pump outdoor frosting conditions. The methods of frosting free air source heat pump by raising air temperature, frosting free air source heat pump by changing air humidity and frosting free air source heat pump by other methods are introduced respectively, the air temperature is changed by additional heat source, and the air humidity is changed by solid dehumidifier or solution dehumidifier, and other methods are to realize frostless air source heat pump through heat source tower and frostless air source heat pump through outdoor air conditioner spraying solution. Finally, the research direction of frostless air source heat pump is prospected: the air source heat pump system with waste heat recovery or solar energy utilization can use waste heat to improve the air temperature flowing through the outdoor heat exchanger to realize frostless. The adsorption capacity and regeneration capacity of solid dehumidifier under low temperature were studied. The regeneration method of dehumidification solution, the source of regeneration energy and the utilization of steam after regeneration were studied. Dehumidification solution and antifreeze solution were further screened.