Patent ID: 7975495

Claim:
A method of adjusting an overall electrical power consumption a refrigerant system that circulates a refrigerant to maintain the indoor air of a comfort zone within a target comfort range, wherein the refrigerant system includes a compressor system having a compressor capacity that is variable in terms of mass flow rate of refrigerant flowing to the compressor system, a condenser fan system having a condenser fan capacity that is variable in terms of airflow volume, and an evaporator fan system having an evaporator fan capacity that is variable in terms of airflow volume, the method comprising: adjusting the compressor capacity; adjusting the evaporator fan capacity; adjusting the condenser fan capacity such that the steps of adjusting the compressor capacity, adjusting the evaporator fan capacity, and adjusting the condenser fan capacity minimizes the overall electrical power consumption of the refrigerant system while maintaining the indoor air of the comfort zone within the target comfort range and keeping the refrigerant flowing to the compressor system at a temp/press value that is above a predetermined minimum temp/press value; periodically reducing the compressor capacity from a first capacity to a reduced capacity, adjusting at least one of the evaporator fan capacity and condenser fan capacity as an attempt to maintain the indoor air within the target comfort range while the refrigerant flowing to the compressor system is above the predetermined minimum temp/press value; if the attempt succeeds, reducing the evaporator fan capacity to a minimum level at which the refrigerant system can still maintain the indoor air within the target comfort range while the compressor capacity is at the reduced capacity and the temp/press value is above the predetermined minimum temp/press value; and if the attempt fails, returning the compressor capacity to the first capacity and adjusting the evaporator fan capacity to the minimum level at which the refrigerant system can still maintain the indoor air within the target comfort range while the compressor capacity is at the first capacity and the refrigerant flowing to the compressor system is above the predetermined minimum temp/press value.