| 摘要 |
PROBLEM TO BE SOLVED: To ensure maximum operation efficiency and hence save electric power by setting timing for starting defrosting so that the average of result coefficients becomes maximum. SOLUTION: Heating operation is started and a compressor 3 is driven. After counting of 10 seconds a microcomputer calculates a cumulative value of input electric power and a cumulative value of heating capability, and divides the cumulative value of the heating capability by the cumulative value of the input electric power to obtain an average result coefficient (average COP). Then, the microcomputer judges whether or not the operation is in defrosting, and if not, it investigates whether or not inlet temperature of an outdoor heat exchanger 2 is lower than a set temperature with a deicer 11 that receives a signal from a temperature sensor 13, and if lower, then it judges whether or not the presently calculated average COP is lower than the previous average COP, and if lower, then defrosting is started until the temperature of the outdoor heat exchanger 2 reaches the set temperature, and after completion it resets the forgoing both cumulative values and the average COP whereby the operation is restarted from the procedure of the first 10 second counting. As the result, operation efficiency is made maximum, and hence power is saved. |
