A transcritical R-744 refrigeration system with a medium temperature section having a plurality of circuits, at least one evaporator receiving an R-744 refrigerant in a medium-pressure liquid state from a receiver and feeding at least one transcritical compressor to compress the R-744 refrigerant from a low-pressure gaseous state into a high-pressure gaseous state to feed a gas cooler and a throttling device to partially condense the R-744 refrigerant into a medium-pressure gaseous-liquid state, the system comprising a pressure reducing valve connected to a discharge conduit of the at least one transcritical compressor and feeding hot gas to a defrost manifold to defrost one of the plurality of circuits of the medium temperature section, wherein the hot gas being fed to the defrost manifold has a pressure value less than or equal to a maximum operating pressure of the at least one evaporator.

The invention relates to a refrigerant for a cooling device (10) comprising a cooling circuit (11) comprising at least one heat exchanger (12), the refrigerant undergoing a phase transition in the heat exchanger, the refrigerant being a refrigerant mixture composed of a fraction of carbon dioxide (CO.sub.2), a fraction of 1,1-difluoroethene and a fraction of at least one other component, wherein the fraction of carbon dioxide in the refrigerant mixture is 45 to 90 mole percent, the fraction of 1,1-difluoroethene being 5 to 40 mole percent.

Efficiency in refrigerant charging work is addressed when a recovered refrigerant recovered from a first heat source unit is to be charged to a second heat source unit. A refrigerant charging method is a charging method used when a first heat source unit of an already installed refrigeration cycle apparatus in which a refrigeration cycle is to be performed by a refrigerant that circulates is to be replaced with a second heat source unit. The refrigerant charging method includes recovering a first refrigerant from an already installed refrigeration cycle apparatus and obtaining a recovered refrigerant and charging the recovered refrigerant and charging a second refrigerant whose composition differs from the composition of the recovered refrigerant to the refrigeration cycle apparatus after renewal that includes the second heat source unit.

Efficiency in refrigerant charging work is addressed when a refrigerant recovered from the first heat source unit is to be charged to a second heat source unit. In a refrigerant charging method in which a first heat source unit of an already installed refrigeration cycle apparatus in which a refrigeration cycle is to be performed by a refrigerant that circulates is replaced with a second heat source unit, transferring the refrigerant from the first heat source unit to the second heat source unit is included. In addition, the method includes measuring the weight of the refrigerant that is transferred from the first heat source unit to the second heat source unit.

An air-conditioning apparatus includes: a housing having a first space and a second space that are adjacent to each other; a fan provided in the first space and to suck air into the housing; a heat exchanger provided in the first space and cause heat exchange with the air sucked by the fan to be performed; a refrigerant sensor provided in the second space and to detect refrigerant; and a partition plate provided to partition off the first space and the second space and having an air inlet port and an air outlet port.

A refrigeration system includes: a leak sensor disposed within a building and configured to measure an amount of refrigerant that has leaked from the refrigeration system within the building; an estimation module configured to determine an estimated amount of refrigerant that has leaked from the refrigeration system within the building based on the measured amount; and a leak module configured to: determine whether a leak is present in the refrigeration system within the building based on the estimated amount of refrigerant that has leaked from the refrigeration system; and take one or more remedial actions when a leak is present in the refrigeration system within the building.

A quench system for a refrigeration cycle of a liquefied natural gas (LNG) facility includes at least one compressor for compressing a refrigerant that cools a natural gas stream. Also included is a quench fluid supply structure containing a quench fluid. Further included is a cooler vessel and a quench fluid line extending from the quench fluid supply structure and through the cooler vessel for cooling therein, the quench fluid maintained in a liquid state through the entirety of the quench fluid line. Yet further included is a quench control valve disposed downstream of the cooler vessel to control a flow rate of the quench fluid routed therein. Also included is a refrigerant suction drum located downstream of the quench control valve and configured to receive the quench fluid from the quench fluid line, the refrigerant suction drum in fluid communication with at least one component for cooling.

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 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 depressurized gas, and the refrigerant is condensed after reaching a certain concentration to become a liquid refrigerant, and then enters an evaporator again for refrigeration.

An object is to provide a novel multi-stage refrigeration apparatus. The object is achieved by a refrigeration apparatus comprising a user-side heat transfer cycle that includes a user-side compressor, a user-side heat exchanger, a user-side pressure-reducing device, and a user-side cascade heat exchanger, and that circulates a user-side refrigerant; a heat-source-side heat transfer cycle that includes a heat-source-side compressor, a heat-source-side heat exchanger, a heat-source-side pressure-reducing device, and a heat-source-side cascade heat exchanger, and that circulates a heat-source-side refrigerant; a cascade heat exchanger configured to exchange heat between the user-side refrigerant of a user-side condenser and the heat-source-side refrigerant of a heat-source-side evaporator; and a control device, the user-side refrigerant having a boiling point of -30° C. or more and 25° C. or less, and the heat-source-side refrigerant having a boiling point of -55° C. or more and less than -30° C.