Based on the difference of refrigerant flux between refrigeration operating condition and heating operating condition in an air-source heat-pump air-conditioning system, the redundant refrigerant flux in winter was applied in three different heat-pump defrosting models including the hot gas bypass defrosting, the sensible heat defrosting and the heat output from refrigerant subcooling. When heating cycle and defrosting cycle took place simultaneously, the defrosting heat utilization ratio, defrosting heat consumption rate and theoretical heating coefficient of these three different defrosting models were calculated respectively. While defrosting at predetermined time, the defrosting time of them was calculated too. Calculating results show that three defrosting models can be used to restrain frosting on the surface of outdoor heat-exchanger effectively in the heating operating air-source heat-pump air-conditioning system with refrigerant flux control. And among them, the heat output from refrigerant subcooling is the best defrosting method. When defrosting at predetermined time, defrosting time of the sensible heat defrosting is the least.%根据风冷热泵空调系统中制冷和制热两种工况下制冷剂流量的差别，将冬季多余的制冷剂流量应用于热气旁通除霜、显热除霜、制冷剂过冷放热除霜三种不同的除霜模式中。当制热循环与除霜循环同时进行时，分别计算了三种不同除霜方式的除霜热量利用率、除霜耗热率以及理论制热系数。当定时除霜时，分别计算了三种不同除霜模式的除霜时间。计算结果表明，在控制制冷剂流量的风冷热泵空调系统中，系统正常制热运行时，三种除霜模式都能够有效地抑制室外换热器表面的结霜，其中制冷剂过冷放热除霜法最佳，定时除霜时，显热除霜所用的除霜时间最少。
展开▼
