A refrigerator includes a first compressor configured to compress first refrigerant, a first condenser configured to condense the compressed first refrigerant, a first expansion valve configured to reduce a temperature and a pressure of the condensed first refrigerant, a first evaporator configured to evaporate the first refrigerant having passed through the first expansion valve, a second compressor configured to compress second refrigerant, a second condenser configured to condense the compressed second refrigerant, a second expansion valve configured to reduce a temperature and a pressure of the condensed second refrigerant, a second evaporator configured to evaporate the second refrigerant having passed through the second expansion valve, a first heat exchanger arranged after and connected to the first expansion valve, and a second heat exchanger arranged after and connected to the second expansion valve. The first heat exchanger and the second heat exchanger are configured to exchange heat with each other.

A refrigerator includes a first compressor configured to compress first refrigerant, a first condenser configured to condense the compressed first refrigerant, a first expansion valve configured to reduce a temperature and a pressure of the condensed first refrigerant, a first evaporator configured to evaporate the first refrigerant having passed through the first expansion valve, a second compressor configured to compress second refrigerant, a second condenser configured to condense the compressed second refrigerant, a second expansion valve configured to reduce a temperature and a pressure of the condensed second refrigerant, a second evaporator configured to evaporate the second refrigerant having passed through the second expansion valve, a first heat exchanger arranged after and connected to the first expansion valve, and a second heat exchanger arranged after and connected to the second expansion valve. The first heat exchanger and the second heat exchanger are configured to exchange heat with each other.

A cooling system with a heat pump function for a motor vehicle is described, includes a base system with a refrigerant compressor. A directly or indirectly working external heat exchanger which is arranged downstream of the refrigerant compressor. A directly or indirectly working first evaporator as part of an air conditioning device for the interior air conditioning of the motor vehicle, arranged down-stream of the external heat exchanger and preceded by a first expansion element. At least one second evaporator as part of a cooling device of an electric drive or storage unit, which evaporator is arranged fluidically parallel to the first evaporator, and which is preceded by a second expansion element. At least one low-pressure side collector arranged downstream of the first and second evaporators, or at least one high-pressure side collector arranged downstream of the external heat exchanger and upstream of the first and second evaporators.

A refrigeration appliance, especially domestic refrigeration appliance, includes a compressor, a condenser, at least a first evaporator, a suction line from the first evaporator to the compressor, at least one heat exchanger switchable between condenser operation and evaporator operation, and a valve arrangement switching the heat exchanger between an evaporator operating state, having a switchable heat exchanger inlet connected to the condenser through a first choke point and a switchable heat exchanger outlet connected to the first evaporator, and a condenser operating state, having the switchable heat exchanger outlet connected to the evaporator through a second choke point. A first supply line for supplying refrigerant in the evaporator operating state and a second supply line, separate therefrom, for supplying refrigerant in the condenser operating state, are associated with the switchable heat exchanger. Only the first supply line is connected with the suction line, forming an external heat exchanger.

A refrigeration appliance, especially domestic refrigeration appliance, includes a compressor, a condenser, at least a first evaporator, a suction line from the first evaporator to the compressor, at least one heat exchanger switchable between condenser operation and evaporator operation, and a valve arrangement switching the heat exchanger between an evaporator operating state, having a switchable heat exchanger inlet connected to the condenser through a first choke point and a switchable heat exchanger outlet connected to the first evaporator, and a condenser operating state, having the switchable heat exchanger outlet connected to the evaporator through a second choke point. A first supply line for supplying refrigerant in the evaporator operating state and a second supply line, separate therefrom, for supplying refrigerant in the condenser operating state, are associated with the switchable heat exchanger. Only the first supply line is connected with the suction line, forming an external heat exchanger.

A refrigeration appliance with multiple storage compartments has a refrigerant circuit with a first expansion valve, a first heat exchanger, a second expansion valve, and a second heat exchanger connected in series between pressure and suction connections of a compressor. Each heat exchanger is associated with at least one storage compartment in order to control its temperature. A control unit controls the compressor rotational speed and positions of the expansion valves. The control unit has a continuously linear regulator for each storage compartment with a P-component for estimating a required temperature control output using a difference between actual and target temperatures. A model computing unit ascertains a target evaporation temperature for a first storage compartment controlled by the first heat exchanger, and for a second storage compartment controlled by the second heat exchanger. The heat exchangers are operated by selecting the compressor rotational speed and the valve positions of the expansion valves.

A refrigeration appliance with multiple storage compartments has a refrigerant circuit with a first expansion valve, a first heat exchanger, a second expansion valve, and a second heat exchanger connected in series between pressure and suction connections of a compressor. Each heat exchanger is associated with at least one storage compartment in order to control its temperature. A control unit controls the compressor rotational speed and positions of the expansion valves. The control unit has a continuously linear regulator for each storage compartment with a P-component for estimating a required temperature control output using a difference between actual and target temperatures. A model computing unit ascertains a target evaporation temperature for a first storage compartment controlled by the first heat exchanger, and for a second storage compartment controlled by the second heat exchanger. The heat exchangers are operated by selecting the compressor rotational speed and the valve positions of the expansion valves.

A process for conditioning air, by means of a main circuit, the main circuit being a vapor compression circuit, wherein a first refrigerant circulates, and a secondary circuit with no compressor, wherein a non-flammable second refrigerant including a hydrofluoroolefin and/or a hydrochlorofluoroolefin circulates, the main circuit and the secondary circuit being coupled to one another; the process including a heat exchange between the surroundings and the first refrigerant, a heat exchange between the first and second refrigerants, and a heat exchange between the second refrigerant and the air to be conditioned. Also, an air conditioning plant for implementing the process.

A refrigeration cycle device includes a heating unit, an air-heating expansion valve, an outdoor heat exchanger, an air-cooling expansion valve, an indoor evaporator, and a cooler-unit expansion valve, a cooler unit, and a refrigerant circuit switching unit. In a heating series cooler-unit mode, refrigerant is circulated in order of the heating unit, the air-heating expansion valve, the outdoor heat exchanger, the cooler-unit expansion valve, and the cooler unit. In a heating parallel cooler-unit mode, refrigerant is circulated in order of the heating unit, the air-heating expansion valve, and the outdoor heat exchanger, and refrigerant is circulated in order of the heating unit, the cooler-unit expansion valve, and the cooler unit.

A system comprising a compressor, a first valve coupled to the compressor and to a first coil, a first expansion valve coupled to the first coil, and a second expansion valve. The second expansion valve coupled to a second coil. A second valve is coupled to the second coil and the compressor. A third valve is coupled to the compressor and a third coil. In response to receiving a heating demand that is below a threshold heating demand, a controller induces an artificial heating demand.