Abstract: A method for charging a field refrigeration system including an evaporator, a condenser, a compressor, and an expansion device includes calculating a field subcooling of the field refrigeration system as a function of a measured field liquid line pressure and a measured field liquid line temperature. A charge adjustment percentage can be calculated as a function of the field subcooling, a measured field indoor wet bulb temperature, and a measured field outdoor dry bulb temperature. A refrigerant adjustment weight can be determined based on the charge adjustment percentage. A field refrigeration system charge can be adjusted by the refrigerant adjustment weight.

Abstract: A method for charging a field refrigeration system including an evaporator, a condenser, a compressor, and an expansion device includes calculating a target superheat as a function of one or more of a measured field outdoor dry bulb temperature, and a measured field indoor wet bulb temperature. A charge adjustment percentage can be calculated as a function of the target superheat. A refrigerant adjustment weight can be determined based on the charge adjustment percentage. A field refrigeration system charge can be adjusted by the refrigerant adjustment weight.

Abstract: A method for controlling an air conditioning system comprises routing refrigerant through an evaporator to cool air in a space, proportioning refrigerant flow from the evaporator between a condenser circuit and a hot gas reheat circuit that heats air leaving the evaporator, routing refrigerant flow from the condenser circuit and the hot gas reheat circuit through an expansion device and back to the evaporator, monitoring a first temperature at the evaporator, stabilizing proportioning of refrigerant flow between the condenser circuit and the hot gas reheat circuit based on the monitored first temperature.

Abstract: Heat pumps that heat or cool a space and that also heat water, refrigerant management systems for such heat pumps, and methods of managing refrigerant charge. Various embodiments remove idle refrigerant from a heat exchanger that is not needed for transferring heat by opening a refrigerant recovery valve and delivering the idle refrigerant from the heat exchanger to an inlet port on the compressor. The heat exchanger can be isolated by closing an electronic expansion valve, actuating a refrigerant management valve, or both. Refrigerant charge can be controlled by controlling how much refrigerant is drawn from the heat exchanger, by letting some refrigerant back into the heat exchanger, or both. Heat pumps can be operated in different modes of operation, and various components can be interconnected with refrigerant conduit. Some embodiments deliver refrigerant gas to the heat exchanger and drive liquid refrigerant out prior to isolating the heat exchanger.

Abstract: Heat pumps for climates where demand for cooling and heating are unequal and methods of adapting and distributing heat pumps for such climates. Heat pumps include a compressor, compressor motor, variable-speed drive, and controller. In a number of embodiments, non-volatile memory stores sets of constant speeds for cooling and heating, and a person can select, via an input device, different sets of speeds for cooling and heating to provide the different cooling and heating capacities. The controller then operates the unit at the selected speeds, selecting from within the set based on demand for cooling or heating. In some embodiments, different sets of speeds may have the same minimum speed but different maximum speeds. Identical heat pumps can be configured to have different capacity ratings and different advertized efficiencies for different climates.

Abstract: Heat pumps for climates where demand for cooling and heating are unequal and methods of adapting and distributing heat pumps for such climates. Heat pumps include a compressor, compressor motor, variable speed drive, and controller. In a number of embodiments, non-volatile memory stores sets of constant speeds for cooling and heating, and a person can select, via an input device, different sets of speeds for cooling and heating to provide the different cooling and heating capacities. The controller then operates the unit at the selected speeds, selecting from within the set based on demand for cooling or heating. In some embodiments, different sets of speeds may have the same minimum speed but different maximum speeds. Identical heat pumps can be configured to have different capacity ratings and different advertised efficiencies for different climates.