A heat-pump system may include a compressor, an outdoor heating exchanger, an indoor heat exchanger, an expansion device, and a supplemental heater. The outdoor heat exchanger may be in fluid communication with the compressor. The indoor heat exchanger may be in fluid communication with the compressor. The expansion device may be in fluid communication with the indoor and outdoor heat exchangers. The supplemental heater may include a burner and a working-fluid conduit. The burner may be configured to burn a fuel and heat the working-fluid conduit. When the heat-pump system is operating in a heating mode, the indoor heat exchanger may receive working fluid from the working-fluid conduit such that the working fluid flows from an outlet of the working-fluid conduit to an inlet of the indoor heat exchanger.

The present disclosure relates to a method and a system for preventing freezing when a four-way valve in a heat pump water heater is failed, which includes following acts: In act S1, it is judged that whether current water temperature T is lower than a preset minimum temperature T.sub.min , for the water tank, if yes, perform act S2; if no, perform act S1 again. In act S2, it is judged that whether a cooling rate Td of the current water temperature T is greater than or equal to a preset rate ΔT; or, it is judged that whether the current water temperature T satisfies T<T.sub.min−a and whether T<T.sub.min−a stands for a first time period t1, in which a is a limit value of a temperature difference; if at least one yes, perform act S3, otherwise, return to act S1. In act S3, a heat pump system is controlled to stop and an electric auxiliary heating system is started. By judging whether a cooling rate Td of the current water temperature T is greater than or equal to a preset rate ΔT; or by judging whether the current water temperature T satisfies T<T.sub.min−a and whether T<T.sub.min−a stands for a first time period t1, it may be judged precisely that whether the four-way valve is failed, which avoids a misjudgment.

The present disclosure relates to a method and a system for preventing freezing when a four-way valve in a heat pump water heater is failed, which includes following acts: In act S1, it is judged that whether current water temperature T is lower than a preset minimum temperature T.sub.min , for the water tank, if yes, perform act S2; if no, perform act S1 again. In act S2, it is judged that whether a cooling rate Td of the current water temperature T is greater than or equal to a preset rate ΔT; or, it is judged that whether the current water temperature T satisfies T<T.sub.min−a and whether T<T.sub.min−a stands for a first time period t1, in which a is a limit value of a temperature difference; if at least one yes, perform act S3, otherwise, return to act S1. In act S3, a heat pump system is controlled to stop and an electric auxiliary heating system is started. By judging whether a cooling rate Td of the current water temperature T is greater than or equal to a preset rate ΔT; or by judging whether the current water temperature T satisfies T<T.sub.min−a and whether T<T.sub.min−a stands for a first time period t1, it may be judged precisely that whether the four-way valve is failed, which avoids a misjudgment.

A recirculating bath includes a reservoir for receiving a working liquid, a recirculating pump, and at least one thermal element. The recirculating pump and thermal element are located externally to the reservoir so that the reservoir has an unobstructed working space. The thermal element may be thermally coupled to the working liquid through an interior surface of the reservoir, or the working liquid may be circulated over the thermal element by the recirculating pump in a chamber external to the reservoir. The recirculating bath may also include a lid that provides access to the reservoir by pivoting on a latching hinge. When open, the lid may provide a working surface adjacent to the reservoir. The lid may also include a selector that unlatches the hinge so that the lid can be removed. The recirculating pump may be fluidically coupled to the reservoir via a manifold.

A semi-open high-temperature heat pump system including a compressor, a direct-contact condenser, a heat exchanger, an evaporator, a water purifier, a cold water pump, a hot water pump, a circulating water pump, and a vacuum pump. A discharge port of the compressor is connected to the direct-contact condenser, the direct-contact condenser is connected to the evaporator via the heat exchanger, and the evaporator is connected to a gas suction port of the compressor via a gas vent on its top. An outlet of the water purifier is separately connected to the compressor, the direct-contact condenser, and the evaporator via the cold water pump. An outlet at the bottom of the evaporator is connected to the direct-contact condenser via the circulating water pump. The vacuum pump is connected above the direct-contact condenser, and the hot water pump is connected below the direct-contact condenser.

Disclosed herein are heat pump systems for water heaters. The heat pump systems can comprise a housing defining an interior chamber, an air inlet, and an air outlet. The air inlet and the air outlet can form an air flow path through the interior chamber, and an evaporator unit can be positioned within the interior chamber such that the air flow path contacts the evaporator unit. The housing can also have a flue pipe having a cross-section to encourage aerodynamic flow and/or side baffles to encourage air flow into the evaporator unit. The housing can also have a second air inlet to increase air flow and a curved elbow around the first air inlet to direct the air flow path. The air flow path can flow from a top side of the housing to a side of the housing, and the air flow path can be reversible.

A receiver, a receiver assembly and a heat pump system. The receiver includes a first pipe, a second pipe and a third pipe leading to the cavity of the receiver, wherein the first pipe, the second pipe and the third pipe connect to a first load unit, a second load unit and a cold and heat source unit, respectively.

A retrofit heat pump system for a water heater is disclosed. The heat pump system includes a plurality of evaporators to increase the efficiency of heat exchange for the system. The system can also include a plurality of condenser circuits used to heat the water of an existing water tank. A fan disposed in a housing of the heat pump system can draw air across the plurality of evaporators and exhaust cool air external to the heat pump system. The cool air can be exhausted into duct work associated with an air conditioning system of the home. The disclosure also describes a refrigerant distributor for providing uniform liquid refrigerant to the plurality of evaporators.

A retrofit heat pump system for a water heater is disclosed. The heat pump system includes a plurality of evaporators to increase the efficiency of heat exchange for the system. The system can also include a plurality of condenser circuits used to heat the water of an existing water tank. A fan disposed in a housing of the heat pump system can draw air across the plurality of evaporators and exhaust cool air external to the heat pump system. The cool air can be exhausted into duct work associated with an air conditioning system of the home. The disclosure also describes a refrigerant distributor for providing uniform liquid refrigerant to the plurality of evaporators.

A semi-open high-temperature heat pump system including a compressor, a direct-contact condenser, a heat exchanger, an evaporator, a water purifier, a cold water pump, a hot water pump, a circulating water pump, and a vacuum pump. A discharge port of the compressor is connected to the direct-contact condenser, the direct-contact condenser is connected to the evaporator via the heat exchanger, and the evaporator is connected to a gas suction port of the compressor via a gas vent on its top. An outlet of the water purifier is separately connected to the compressor, the direct-contact condenser, and the evaporator via the cold water pump. An outlet at the bottom of the evaporator is connected to the direct-contact condenser via the circulating water pump. The vacuum pump is connected above the direct-contact condenser, and the hot water pump is connected below the direct-contact condenser.