초록 ▼

A microcomputer based defrost control for a heat pump system that “learns”from previous defrost cycles to achieve optimum defrost control at each of a plurality of outdoor temperature ranges, even if the heat pump system operating parameters change due to system aging. At the conclusion of each defr

A microcomputer based defrost control for a heat pump system that “learns”from previous defrost cycles to achieve optimum defrost control at each of a plurality of outdoor temperature ranges, even if the heat pump system operating parameters change due to system aging. At the conclusion of each defrost cycle, the control determines the differential temperature between the outdoor ambient air and the outdoor heat exchanger and compares that value to a value stored in microcomputer memory representing a previous best such post-defrost differential temperature for the same ambient air temperature range. The control then calculates a defrost differential temperature initiate value, corrected to compensate for any loss of defrost performance indicated by the current post-defrost cycle differential temperature. After a period of time during which a number of defrost cycles have occurred, the minimum post defrost differential temperature value for each ambient temperature range becomes the best performance measure of the defrost cycle for the heat pump system. The stored minimum values are reset to zero when the control and heat pump system are deenergized. When the system is again turned on, new optimum defrost initiate values are again determined over a period of time. In addition, various default conditions cause the control to initiate an extended defrost cycle. The control is programmed to alert the operator by lighting a lamp on the thermostat should such a fault condition occur.

대표청구항 ▼

A defrost control for a temperature conditioning system that includes an outdoor heat exchanger, said control comprising: a. an outdoor heat exchanger temperature sensor; b. an outdoor ambient air temperature sensor; and c. means connected to both the outdoor heat exchanger temperature sensor and th

A defrost control for a temperature conditioning system that includes an outdoor heat exchanger, said control comprising: a. an outdoor heat exchanger temperature sensor; b. an outdoor ambient air temperature sensor; and c. means connected to both the outdoor heat exchanger temperature sensor and the outdoor ambient air temperature sensor and responsive thereto, for controlling the system to effect a defrost cycle to melt ice and frost that have collected on the outdoor heat exchanger when the heat exchanger was used as an evaporator, if the current differential temperature between the outdoor ambient air and the outdoor heat exchanger exceeds a defrost initiate value calculated after each defrost cycle as a function of: i. a post defrost cycle differential temperature between the outdoor ambient air and the outdoor heat exchanger determined by the control means following the last defrost cycle, generally before new frost and ice formed on the outdoor heat exchanger; and ii. a minimum such post-defrost cycle differential temperature from differential temperatures determined following previous defrost cycles as in (i), at substantially the same outdoor ambient air temperature; whereby said defrost cycle initiate value reiteratively determined by said control means, in time approaches an optimum value that changes as the temperature conditioning system changes and thus adapts to maintain an optimum defrost cycle.