A liquefier for a heat pump includes a liquefier space, a compressor motor and a motor fixture for holding the stationary motor part, wherein the motor further has a motor shaft and a compressor wheel connected to the motor shaft. The motor fixture is formed so that the stationary motor part is held so that it is in contact with liquefied working fluid when liquefied working fluid is filled in the liquefier space. Furthermore, the compressor wheel extends into a region of the heat pump in which a channel for gaseous working fluid to be compressed passes.

An air conditioning system includes a heat pump section performing indoor air-warming by using a vapor-compression refrigeration cycle, a separate heat source section performing indoor air-warming by using a heat source separate from the heat pump section, and a control unit configured to control actions of the heat pump section and the separate heat source section. When a heat pump air-warming operation is being performed, and when a first switching condition is met, the control unit switches from the heat pump air-warming operation to a separate heat source air-warming operation. The first switching condition is that an outside air temperature reaches a first switching outside air temperature and an air-warming capability of the heat pump section reaches an upper limit.

An air conditioning system includes a heat pump section performing indoor air-warming by using a vapor-compression refrigeration cycle, a separate heat source section performing indoor air-warming by using a heat source separate from the heat pump section, and a control unit configured to control actions of the heat pump section and the separate heat source section. When a heat pump air-warming operation is being performed, and when a first switching condition is met, the control unit switches from the heat pump air-warming operation to a separate heat source air-warming operation. The first switching condition is that an outside air temperature reaches a first switching outside air temperature and an air-warming capability of the heat pump section reaches an upper limit.

An apparatus comprises a subcooler, such as a vented tube/plate or tube on tube heat exchanger, and a pre-cooler and/or post-heater, which may be a vented tube/plate or tube on tube heat exchanger. The subcooler and pre-cooler and/or post-heater are connected in fluid communication with each other (in series) and with a refrigerant output and input of a condenser. For example, the refrigerant output goes into the subcooler, and the refrigerant input comes out of the precooler and/or post-heater. A working fluid (e.g. coolant), such as water or glycol or other working fluid, is forced, such as by pumping, first through the subcooler and then through the precooler and/or post-heater. Flow rate of the working fluid through the apparatus may be regulated such that the refrigerant is first subcooled to an incoming fluid's temperature and then to pre-cool the refrigerant to approximately its saturated-vapor state, when the system is operating to provide a refrigeration effect. Heat absorbed by the working fluid using the method may heat a potable hot water system or as a secondary heat source.

An apparatus comprises a subcooler, such as a vented tube/plate or tube on tube heat exchanger, and a pre-cooler and/or post-heater, which may be a vented tube/plate or tube on tube heat exchanger. The subcooler and pre-cooler and/or post-heater are connected in fluid communication with each other (in series) and with a refrigerant output and input of a condenser. For example, the refrigerant output goes into the subcooler, and the refrigerant input comes out of the precooler and/or post-heater. A working fluid (e.g. coolant), such as water or glycol or other working fluid, is forced, such as by pumping, first through the subcooler and then through the precooler and/or post-heater. Flow rate of the working fluid through the apparatus may be regulated such that the refrigerant is first subcooled to an incoming fluid's temperature and then to pre-cool the refrigerant to approximately its saturated-vapor state, when the system is operating to provide a refrigeration effect. Heat absorbed by the working fluid using the method may heat a potable hot water system or as a secondary heat source.

A fenestration assembly comprising a sliding glass assembly that slides between a fully closed position and a fully open position in which the sliding glass assembly is received into a pocket of the fenestration assembly. The pocket is covered on at least one side with insulation. The fenestration assembly may have two sliding glass assemblies. The fenestration assembly may be used in an energy efficient building system.

A fenestration assembly comprising a sliding glass assembly that slides between a fully closed position and a fully open position in which the sliding glass assembly is received into a pocket of the fenestration assembly. The pocket is covered on at least one side with insulation. The fenestration assembly may have two sliding glass assemblies. The fenestration assembly may be used in an energy efficient building system.

An apparatus for heating water has a tank for storing water and an air conditioning system that defines a refrigerant flow path through which refrigerant flows. The refrigerant flow path passes through the heat exchanger so that refrigerant heat is contributed to the tank. A control system controls operation of the water heating apparatus.

An apparatus for heating water has a tank for storing water and an air conditioning system that defines a refrigerant flow path through which refrigerant flows. The refrigerant flow path passes through the heat exchanger so that refrigerant heat is contributed to the tank. A control system controls operation of the water heating apparatus.

A heat pump water heater appliance includes a tank that defines an interior volume. A drain pan is positioned below an evaporator of a sealed system. A liquid monitoring sensor has a voltage divider with a pair of probes. The probes of the pair of probes extend into the drain pan. A related method for operating a heat pump water heater appliance is also provided.