초록 ▼

A control and method for defrosting the outdoor heat exchanger of an air source heat pump. A defrost cycle is initiated when ice and frost have accumulated on the outdoor heat exchanger sufficiently such that, as a function of the indoor temperature of a comfort zone, the maximum permissible heat tr

A control and method for defrosting the outdoor heat exchanger of an air source heat pump. A defrost cycle is initiated when ice and frost have accumulated on the outdoor heat exchanger sufficiently such that, as a function of the indoor temperature of a comfort zone, the maximum permissible heat transfer degradation at which the efficiency and reliability of the temperature conditioning system are optimized, has occurred. Heat transfer degradation is determined from the outdoor ambient air temperature and the temperature of either the outdoor heat exchanger, or the compressor suction line. If the temperature of the outdoor heat exchanger or the suction line is less than a predetermined value, a deferred defrost cycle is initiated wherein the defrost cycle starts after a fixed time interval has elapsed. The defrost cycle is terminated when the relative tempratures of the outdoor heat exchanger and the outdoor ambient air indicate that sufficient frost is melted from the heat exchanger to insure adequate time between successive defrost cycles for optimizing the efficiency and reliability of the system, or after a predetermined time interval has elapsed, whichever condition occurs first.

대표청구항 ▼

In an air source heat pump for temperature conditioning a comfort zone, including an outdoor heat exchanger, an indoor heat exchanger, a compressor connected to a reversing valve by a refrigerant suction line, and means for moving air through the outdoor and indoor heat exchangers in heat transfer r

In an air source heat pump for temperature conditioning a comfort zone, including an outdoor heat exchanger, an indoor heat exchanger, a compressor connected to a reversing valve by a refrigerant suction line, and means for moving air through the outdoor and indoor heat exchangers in heat transfer relation therewith, a control for desfrosting the outdoor heat exchanger to melt ice and frost accumulated thereon during operation of the heat pump in a heating mode, said control comprising (a) means for sensing a condition indicative of the relative water vapor content of the outdoor ambient air; (b) means for sensing frost and ice accumulation on the outdoor heat exchanger; (c) a sensor for sensing the temperature in the comfort zone; and (d) control means, responsive to said condition sensing means, to said means for sensing frost and ice accumulation, and to the comfort zone temperature sensor, and operative to initiate: (i) a deferred defrost cycle wherein defrost of the outdoor heat exchanger begins after a fixed time interval has elapsed, if said condition sensing means indicates that the water vapor content of the outdoor air is relatively low; and (ii) an immediate defrost cycle when frost and ice have accumulated on the outdoor heat exchanger sufficiently to degrade heat transfer efficiencey to an optimum permissible limit, determined as a function of the comfort zone temperature.