Abstract: A method for providing controllable amounts of heat recovery from a refrigerant circuit includes the steps of providing a cooling circuit comprising a compressor, a condenser, an expansion device and an evaporator connected in series by refrigerant flow lines; providing a heat recovery circuit comprising a heat recovery heat exchanger, the heat recovery circuit being connected to the cooling circuit so that the heat recovery heat exchanger is in parallel with the condenser, and the heat recovery heat exchanger being in heat exchange relationship with a fluid to be heated based upon an end-user demand for heat; and selectively flowing refrigerant through the condenser of the cooling circuit and the heat recovery heat exchanger of the heat recovery circuit so as to maintain temperature of the fluid within a temperature hand around a set point provided by the end user.

Abstract: An air conditioning system is disclosed which takes advantage of low ambient temperature conditions so as to activate a refrigerant flow that bypasses the compressor. The activation of the refrigerant flow is achieved by the intelligent control of a pump positioned between the outlet of the condenser and the inlet of an expansion device upstream of the evaporator. The refrigerant flow produced by the pump does not require any particular positioning of the condenser and evaporator components with respect to each other. The evaporator preferably absorbs heat from water circulating in a secondary loop which is used to remove heat from a building by one or more fan coil units.

Abstract: An air conditioning system is disclosed which takes advantage of low ambient temperature conditions so as to activate a refrigerant flow that bypasses the compressor. The activation of the refrigerant flow is achieved by the intelligent control of a pump positioned between the outlet of the condenser and the inlet of an expansion device upstream of the evaporator. The refrigerant flow produced by the pump does not require any particular positioning of the condenser and evaporator components with respect to each other. The evaporator preferably absorbs heat from water circulating in a secondary loop which is used to remove heat from a building by one or more fan coil units.

Abstract: An expansion valve is controlled in response to sensing conditions at the outlet of at least one compressor within a refrigeration loop in a manner that achieves low suction superheat operation of the compressor. In particular, a discharge superheat is computed using data obtained from a specific mathematical model of the compression process corresponding to the current capacity stage of the compressor. The position of the expansion valve is controlled so as to result in an actual discharge superheat being within a predetermined dead band amount of the computed discharge superheat.