PULSE WIDTH MODULATION CONTROL FOR HEAT PUMP FAN TO ELIMINATE COLD BLOW

摘要

A heat pump refrigerant system is provided with a pulse width modulation control for a fan moving air over the indoor heat exchanger. When it is determined that there is insufficient heat rejected by the indoor heat exchanger to heat the volume of air being delivered by the fan into the conditioned environment, the volume of air supplied to the conditioned environment is reduced by utilizing one of pulse width modulation techniques to cycle the indoor fan motor to reduce the average volume of supplied air. Therefore, a precise control over the temperature of air delivered to the conditioned space is achieved, temperature of the delivered air is increased to the target value, and so-called "cold blow" conditions are avoided.