REFRIGERATION AND AIR-CONDITIONING DEVICE

摘要

Provided is a refrigeration and air-conditioning device which is capable of performing a defrosting operation while continuing a heating operation even when the heating operation is performed under air conditions which lead to the formation of frost, and which is capable of ensuring an appropriate amount of ventilation and achieving an improvement in heating comfort. This refrigeration and air-conditioning device has multiple refrigeration cycles which are capable of independently performing heating operations and defrosting operations. Before a defrosting operation a preliminary ventilation operation is performed, wherein the ventilation damper of the indoor unit performing the defrosting operation is controlled and the amount of ventilation is increased, thus ensuring the necessary time-averaged amount of ventilation even during the defrosting operation. When the preliminary ventilation operation is completed, the defrosting operation begins.