Abstract: A heat pump system includes a refrigerant circuit, at least one compressor, an evaporator, and a controller programmed to defrost the evaporator in a defrost mode, wherein in the defrost mode the controller is programmed to monitor the evaporator to detect frost creation thereon, and reduce the speed of the at least one compressor and/or reduce the number of some, but not all operating compressors of the at least one compressor, if frost creation is detected on the evaporator. In some embodiments, the controller is programmed to defrost the evaporator in a second defrost mode. In the second defrost mode the controller is programmed to monitor the evaporator to detect frost creation thereon, turn off the at least one compressor when frost is detected on the evaporator, and operate a fan to force ambient air over the evaporator to defrost the evaporator.

Abstract: A heat pump system includes a refrigerant circuit, at least one compressor, an evaporator, and a controller programmed to defrost the evaporator in a defrost mode, wherein in the defrost mode the controller is programmed to monitor the evaporator to detect frost creation thereon, and reduce the speed of the at least one compressor and/or reduce the number of some, but not all operating compressors of the at least one compressor, if frost creation is detected on the evaporator. In some embodiments, the controller is programmed to defrost the evaporator in a second defrost mode. In the second defrost mode the controller is programmed to monitor the evaporator to detect frost creation thereon, turn off the at least one compressor when frost is detected on the evaporator, and operate a fan to force ambient air over the evaporator to defrost the evaporator.

Abstract: A refrigerant vapor compression system and a method of controlling the system are adapted for controlling the distribution of cooling capacity between two or more temperature controlled zones.

Abstract: A refrigerant vapor compression system and a method of controlling the system are adapted for controlling the distribution of cooling capacity between two or more temperature controlled zones.

Abstract: An air conditioning system to improve indoor air quality (“IAQ”) comprises an air conditioner to receive indoor air from an indoor space and to heat or cool the air, the air conditioner to then return conditioned air to the indoor space. An IAQ option board (“IOB”), electrically coupled to the air conditioner control board, is configured to accept electrical inputs from at least one IAQ sensor. A fresh air damper is electrically connected to the IOB, the IOB controlling the position of the fresh air damper valve. An air purifier is situated such that air from the indoor space passes through the purifier. The operation of state of operation of the purifier is based at least in part on the input from at least one IAQ sensor to improve the IAQ of the indoor space.