초록 ▼

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

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.

대표청구항 ▼

A method for controlling the defrosting of a heat transfer unit of a temperature conditioning system by initiating a defrost operation when a predetermined amount of frost has accumulated on the unit during a frost accumulation period that occurs between defrost operations, said method being of the

A method for controlling the defrosting of a heat transfer unit of a temperature conditioning system by initiating a defrost operation when a predetermined amount of frost has accumulated on the unit during a frost accumulation period that occurs between defrost operations, said method being of the type comprising the steps: determining the time required to actually defrost said unit during an actual defrost operation; increasing the frost accumulation period before initiating the next defrost operation if the time to complete the last defrost was less than said desired defrost time period; or decreasing the frost accumulation period before initiating the next defrost operation if the time to complete the last defrost was greater than said desired defrost time period; improved wherein said determining the time to actually defrost said unit comprises the step of determining the time period required to raise the temperature of said heat transfer unit from a first predetermined temperature to a second predetermined temperature.