Proper deicing end detection and defrost cycle optimization

Abstract

A method of defrost operation optimization in a heat pump includes launching a heating mode after completion of a performed defrost operation, measuring, after launching the heating mode, a heat transfer capability, determining if the measured heat transfer capability is less than or equal to a predetermined heat transfer capability limit for a non-iced condition, and reinforcing a next defrost operation if the measured heat transfer capability is greater than the predetermined gap limit.

1 . A method of defrost operation optimization in a heat pump, the method comprising:
 launching a heating mode after completion of a previously performed defrost operation, wherein the previously performed defrost operation consists of a single defrost cycle;   measuring, after launching the heating mode, a temperature gap between an outdoor temperature and an evaporation temperature;   determining if the temperature gap is less than or equal to a predetermined gap limit for a non-iced condition, wherein the predetermined gap limit is based on a temperature gap value of the heat pump, determined in a laboratory, without ice; and   reinforcing a next defrost operation if the temperature gap is greater than the predetermined gap limit.   
     
     
         2 . The method of  claim 1 , wherein the heat pump comprises a heat exchanger exposed to ice accumulation conditions;
 one or more sensors to monitor the outdoor temperature and the evaporation temperature;   a memory storing the predetermined gap limit; and   a defrost optimization module incorporated within a processor and configured to measure the temperature gap between the outdoor temperature and the evaporation temperature, and to compare the temperature gap to the predetermined gap limit.   
     
     
         3 . The method of  claim 1 , wherein the reinforcing comprises one or more of increasing, relative to the previously performed defrost operation, a number of defrost cycles, a condensing temperature, and a defrost time. 
     
     
         4 . (canceled) 
     
     
         5 . The method of  claim 1 , wherein the measuring is performed during a stable time after the launching the heating mode. 
     
     
         6 . The method of  claim 1 , wherein the measuring is performed within about 30 seconds and 300 seconds after the launching the heating mode. 
     
     
         7 . The method of  claim 1 , wherein the measuring is performed at about 180 seconds after the launching the heating mode. 
     
     
         8 . The method of  claim 1 , wherein the measuring the temperature gap is performed at determined operating conditions. 
     
     
         9 . (canceled) 
     
     
         10 . The method of  claim 1 , wherein the temperature gap value is determined at known ambient temperatures. 
     
     
         11 . The method of  claim 1 , wherein the temperature gap value is determined with the heat pump operating at nominal operating parameters; and
 the launching the heating mode comprises operating the heat pump at determined operating parameters substantially corresponding to the nominal operating parameters, wherein the operating parameters comprise a compressor capacity, indoor fan speed, and outdoor fan speed.   
     
     
         12 . The method of  claim 11 , wherein the reinforcing comprises one or more of increasing, relative to the performed defrost operation, a number of defrost cycles, a condensing temperature, and a defrost time. 
     
     
         13 . The method of  claim 12 , wherein the measuring is performed within about 30 seconds and 300 seconds after the launching the heating mode. 
     
     
         14 . A method of defrost operation optimization in a heat pump, the method comprising:
 launching a heating mode after completion of a previously performed defrost operation, the previously performed defrost operation consisting of a single defrost cycle;   measuring, within about 30 seconds and 300 seconds after launching the heating mode, a heat transfer capability of the heat pump;   determining if the heat transfer capability is less than or equal to a predetermined heat transfer capability limit for a non-iced condition, wherein the heat transfer capability limit is based on a temperature gap value of the heat pump, determined in a laboratory, without ice; and   reinforcing a next defrost operation if the measured heat transfer capability is greater than the predetermined heat transfer capability limit.   
     
     
         15 . The method of  claim 14 , wherein the measuring the heat transfer capability is performed in determined operating conditions. 
     
     
         16 . The method of  claim 15 , wherein the determined operating conditions comprise an outdoor temperature and a fan speed. 
     
     
         17 . The method of  claim 15 , wherein the heat transfer capability is a temperature gap between an outdoor temperature and an evaporation temperature. 
     
     
         18 . The method of  claim 15 , wherein the heat transfer capability is an air pressure differential across a heat exchanger. 
     
     
         19 . A method of defrost operation optimization in a heat pump, the method comprising:
 launching a heating mode after completion of a previously performed defrost operation, the previously performed defrost operation consisting of a single defrost cycle;   measuring, after launching the heating mode, an air pressure differential across an outdoor heat exchanger;   determining if the air pressure differential is less than or equal to a predetermined differential limit for a non-iced condition; and   reinforcing a next defrost operation if the air pressure differential is greater than the predetermined differential limit.   
     
     
         20 . The method of  claim 19 , wherein the measuring the air pressure differential is performed in determined operating conditions; and
 the predetermined differential limit is based on an air pressure differential value of the heat pump without ice determined at operating conditions corresponding to the determined operating conditions.