Abstract
Methods to shorten the defrost time have been studied on a heat pump air conditioner. The experiment has been carried out using a 0.75kW heat pump and the energy balance during defrosting has been analyzed. We have found that the following methods are effective to shorten the defrost time; (1) Increase in power inqut to the compressor during defrosting, (2) Utilization of the compressor for thermal energy storage, (3) Reduction of the water left on the outdoor heat exchanger fins.
The heat pump with the new defrosting system has been made on an experimental basis. lts defrost time is 1 minute and 55 seconds under the defrost condition of the Japanese Industrial Standard.
The defrost time of a conventional heat pump is about 4 or 5 minutes.
