초록 ▼

A demand defrost controller for a heat pump. The controller compares the temperature of an outdoor heat exchange coil with an enable temperature. A timer is activated when the coil temperature is less than the enable temperature. When the timer senses the compressor has run for a predetermined time

A demand defrost controller for a heat pump. The controller compares the temperature of an outdoor heat exchange coil with an enable temperature. A timer is activated when the coil temperature is less than the enable temperature. When the timer senses the compressor has run for a predetermined time the controller checks outdoor and coil temperatures to determine if a defrost cycle of the heat pump should be conducted. A defrost cycle is achieved by reversing refrigerant flow in the heat pump system for a predetermined period or until the outdoor heat exchange coil has been heated to a termination temperature.

대표청구항 ▼

A method of defrosting an outdoor heat exchanger of a compressor-condenser-evaporator type heat pump unit in accordance with sensed conditions indicative of the need to perform a defrost cycle comprising: (a) sensing the temperature of the outdoor heat exchanger; (b) sensing the outdoor air temperat

A method of defrosting an outdoor heat exchanger of a compressor-condenser-evaporator type heat pump unit in accordance with sensed conditions indicative of the need to perform a defrost cycle comprising: (a) sensing the temperature of the outdoor heat exchanger; (b) sensing the outdoor air temperature; (c) monitoring compressor running time until a predetermined accumulated running time that varies as a function of outdoor air temperature has elapsed; (d) enabling defrosting of the outdoor heat exchanger when said running time has elapsed; (e) detecting the extent of the temperature differential between the sensed outdoor heat exchanger temperature and the sensed outdoor air temperature; (f) determining a value indicative of the frosting condition of the heat exchanger which valve varies as a function of outdoor air temperature; (g) comparing the value with the sensed temperature differential; (h) enabling a defrosting cycle when the sensed temperature differential and the value bear a predetermined relationship to each other; and, (i) initiating a defrost cycle only when enabled by said compressor running time elapsing and enabled by said sensed temperature differential bearing a predetermined relationship to said value.