A heat pump system and a method for operating this system type includes a heat pump circuit for a heat pump circuit medium flowing through a primary side of a heat exchanger, and a heating circuit for a heating circuit medium flowing through the heat exchanger secondary side. A heat circuit pump is connected upstream of the exchanger secondary side when viewed in the heating circuit medium operating flow direction. When viewed in the heating circuit medium operating flow direction, a check valve connected downstream of the heating circuit pump and upstream of the secondary side closes when a heating circuit medium flows opposite the operating flow direction, and a degassing unit connected downstream of the secondary side when viewed in the operating flow direction prevents a flow of the heating circuit medium in the operating flow direction from a predefined gas amount in the heating circuit medium.

Technologies are provided for preventing a working fluid leak from pooling and thus diluting any leaked working fluid from air within a condenser and/or evaporator compartment of the CCU. This can include a computer-readable medium that stores executable instructions that, upon execution, prevent a working fluid leak from pooling within a climate-control unit (CCU) of a transport climate control system. This also includes detecting fulfillment of activation threshold conditions in connection with the CCU. Also, this includes activating a fan in at least one of a condenser unit and an evaporator unit included in the CCU to dilute leaked working fluid from air within the CCU. Further, this includes detecting fulfillment of de-activation threshold conditions and de-activation of an activated fan.

A refrigeration system configured to receive a refrigerant is provided, as well as a walk-in refrigeration unit configured to utilize said system. The refrigeration system comprises: a power source, a condenser unit, an evaporation unit, a plurality of compressors, wherein each of the plurality of compressors is communicably coupled to the condenser unit, and a plurality of expansion devices, wherein each of the plurality of expansion devices is communicably coupled to the evaporation unit. The system is configured to receive an A3 refrigerant having a Global Warming Potential (GWP) value less than 10.

A system and method of retrofitting a heating, ventilation, air conditioning, and refrigeration system (HVACR) including one or more brazed, soldered, or mechanical connections between refrigerant lines is disclosed. The method includes removing a refrigerant from the HVACR system. The refrigerant that is removed is a non-flammable refrigerant. An enclosure is installed over the one or more brazed, soldered, or mechanical connections between refrigerant lines. A refrigerant is added to the HVACR system. The refrigerant being added has a global warming potential (GWP) that is relatively lower than the refrigerant removed from the HVACR system. The refrigerant being added has a relatively higher flammability than the refrigerant removed from the HVACR system.

A refrigerant composition comprising carbon dioxide (CO.sub.2; R-744) and from 1 to 32 weight % difluoromethane (R-32) based on the total weight of the composition is described. Also described is the use of the refrigerant composition for providing heating and cooling and a refrigeration, air-conditioning or heat pump system comprising the refrigerant composition.

Disclosed are a carbon dioxide overlapping type heating system and a control method therefor. The heating system comprises a low-temperature stage loop, a high-temperature stage loop and a heat supply loop, wherein a low-temperature stage compressor (3) and a high-temperature stage compressor (7) are both variable-frequency compressors; and a water pump (10) is a variable-frequency water pump.

A pressure relief arrangement in refrigerant circuits with one high-pressure side and one low-pressure side, which is characterized in that the high-pressure side is fluidically connected with the low-pressure side of the refrigerant circuit via an overpressure relief device, wherein the overpressure relief device causes pressure reduction of the overpressure in the case of overpressure on the high-pressure side and fluid flows from the high-pressure side to the low-pressure side of the refrigerant circuit.

A method of producing a fluoroolefin includes contacting a compound of formula (1), R.sub.fCX.sub.1═CHCF.sub.3, with a fluorinated ethylene compound of formula (2), CX.sub.2X.sub.3═CX.sub.4X.sub.5 in the presence of a catalyst. In the compound of formula (1), R.sub.f is a linear or branched C.sub.1-C.sub.10 perfluorinated alkyl group and Xi is H, Br, Cl, or F. In the compound of formula (2), X.sub.2, X.sub.3, X.sub.4, and X.sub.5 are each independently H, Br, Cl, or F and at least three of X.sub.2, X.sub.3, X.sub.4, and X.sub.5 are F. The resulting composition comprises a compound of formula (3), R.sub.f(CF.sub.2).sub.nCX.sub.6═CH(CF.sub.2).sub.mCX.sub.7X.sub.8CFX.sub.9X.sub.10. In the compound of formula (3), X.sub.6, X.sub.7, X.sub.8, X.sub.9, and X.sub.10 are each independently H, Br, Cl, or F, and the total number of each of H, Br, Cl, and F corresponds to the total number of each of H, Br, Cl, and F provided by the compounds of formulae (1) and (2).

The present disclosure discloses a refrigerator based on a molecular sieve, including a first molecular sieve device, a second molecular sieve device, a reversing valve, and a balancing valve, wherein an air flow alternately passes through the first molecular sieve device and the second molecular sieve device through the reversing valve, and then flows back through the balancing valve, so that the first molecular sieve device and the second molecular sieve device are regenerated. The first molecular sieve device and the second molecular sieve device are capable of separating a refrigerant from a depressurization gas, and the refrigerant is condensed after reaching a certain concentration to become a liquid refrigerant, and then enters an evaporator again for refrigeration.

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.