| 摘要 |
A defrost system adapted for use with refrigeration or heat pump systems wherein an evaporator coil defrost cycle is adaptively modified in response to changing environmental conditions. Under normal conditions, a defrost operation is effected at the end of a period of frost accumulation. The period of frost accumulation is adjusted in accordance with deviation from a desired defrost time of the time required to raise the temperature of the coil from a first predetermined temperature to a second predetermined temperature. If a predetermined maximum defrost period is exceeded, the frost accumulation period is set to a predetermined value. During the frost accumulation period, the differential between the temperature of the coil and ambient temperature is determined, and the frost accumulation period terminated and a defrost operation initiated if temperature differential exceeds a target differential.
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