Experimental Study on Air Source Heat Pump With Multiple Parallel Outdoor Machines Defrosting Alternatively

To solve the problem of reverse-cycle defrosting of large and medium air source heat pump, a new type of air source heat pump cycle with multiple parallel outdoor machines defrosting alternatively was proposed. By switching valves to realize an outdoor machine defrosting, the rest of the outdoor machines were in the state of normal evaporative heat absorption at the same time. In the case of non-stopping heating, defrosting can be realized while recovering frost thawing cooling capacity. A test platform of research system was built in an artificial environment room. The law of the variation of the compressor suction, exhaust pressure and the system thermal performance in the condition of frost free, frosting and defrosting were discussed.