A defrost system includes: a cooling device in a freezer, and includes a casing, a heat exchanger pipe with a difference in elevation in the casing, and a drain receiver unit below the heat exchanger pipe; a refrigerating device to cool and liquefy CO.sub.2 refrigerant; and a refrigerant circuit for permitting the cooled and liquefied CO.sub.2 refrigerant to circulate to the heat exchanger pipe. The defrost system includes a bypass pipe of the heat exchanger pipe to form a CO.sub.2 circulation path; an on-off valve in the heat exchanger pipe to be closed during defrosting so that the CO.sub.2 circulation path is a closed circuit; a pressure adjusting unit for adjusting pressure of the CO.sub.2 refrigerant during defrosting; and a brine circuit as a first heating medium, in which the defrost system permits the CO.sub.2 refrigerant to naturally circulate in the closed circuit during defrosting by a thermosiphon effect.

A refrigeration system includes a compressor having a first stage and a second stage; a heat rejecting heat exchanger including an inter-cooler and a gas cooler, the intercooler coupled to an outlet of the first stage and the gas cooler coupled to an outlet of the second stage; an unload valve coupled to an outlet of the intercooler and a suction port of the first stage; a flash tank coupled to an outlet of the gas cooler; a primary expansion device coupled to an outlet of the flash tank; a heat absorbing heat exchanger coupled to an outlet of the primary expansion device, an outlet of the heat absorbing heat exchanger coupled to the suction port of the first stage; and a controller for executing a startup process including controlling the unload valve to direct refrigerant from the intercooler to the suction port of the first stage.

Provided are mixed refrigerant systems and methods and, more particularly, to a mixed refrigerant system and methods that provides greater efficiency and reduced power consumption via control of a liquid level in a cold vapor separator device.

A refrigeration cycle apparatus according to the present disclosure includes an evaporator, a first compressor, an intercooler, a second compressor, a condenser, and a refrigerant liquid supply passage. The intercooler stores refrigerant liquid and also cools refrigerant vapor compressed by the first compressor and expels it. The second compressor sucks in the refrigerant vapor expelled from the intercooler and compresses it. The intercooler includes a container, an intercooling passage, and a pump. The container contains a vapor space and stores refrigerant liquid. The intercooling passage is a passage in which a part of the refrigerant liquid stored in the container flows and that supplies the part of the refrigerant liquid to the vapor space. The pump pumps a part of the refrigerant liquid stored in the container to the vapor space.

A system for separating a soluble solution includes a first freezer configured to receive a liquid feed stream and a refrigerant stream, and discharge a concentrated solution stream, wherein the first freezer is configured to exchange heat between the liquid feed stream and the refrigerant stream through direct contact within the first freezer and freeze a portion of the liquid feed stream, a first separator external to the first freezer and configured to separate ice particles from the concentrated solution stream and recirculate the concentrated solution stream to the first freezer, and a first ice washer coupled to the first separator and configured to receive the ice particles separated from the concentrated solution stream by the first separator and wash the separated ice particles to free the ice particles from contaminants.

An intermediate unit includes a liquid-side pipe, a first valve, and a refrigerant pressure sensor. The liquid-side pipe is connected to a liquid connection pipe connecting a heat source unit and a utilization unit together. A controller of the intermediate unit adjusts the opening degree of the first valve based on a value measured by the refrigerant pressure sensor. The pressure of a refrigerant to be sent through the liquid connection pipe from the intermediate unit to the utilization unit is adjusted by the first valve.

A thermal management system includes a closed dynamic cooling circuit, and a closed first steady-state cooling circuit. Each circuit has its own compressor, heat rejection exchanger, and expansion device. A thermal energy storage (TES) system is configured to receive a dynamic load and thermally couple the dynamic cooling circuit and the first steady-state cooling circuit. The dynamic cooling circuit is configured to cool the TES to fully absorb thermal energy received by the TES when a dynamic thermal load is ON, and the steady-state cooling circuit is configured to cool the TES when the dynamic thermal load is OFF.

An air conditioner (1A) as a refrigeration apparatus includes: a refrigerant circuit (2) including an evaporator (25), a first compressor (21), a vapor cooler (3), a second compressor (22), and a condenser (23) that are connected in this order; a heat release circuit (4) that allows a heat medium to circulate between the condenser (23) and a first heat exchanger (5) that releases heat to the atmosphere; and a heat absorption circuit (6) that allows a heat medium to circulate between the evaporator (25) and a second heat exchanger (7). The vapor cooler (3) is a heat exchanger that exchanges heat between a refrigerant vapor compressed by the first compressor (21) and the heat medium flowing in the heat release circuit (4) or the heat medium flowing in the heat absorption circuit (6).

Provided is a refrigeration apparatus which can reduce outlet pressure of a refrigerator even in overload conditions and which can improve refrigeration capacity by liquefying a refrigerant in an intermediate cooler. When outlet pressure of a refrigerator 2 is higher than critical pressure, a control apparatus 60 performs control to reduce the opening degree of a decompression electric valve 31 at the upstream side of an intermediate cooler 30. Thereby, the refrigerant is liquefied by gas-liquid separation in the intermediate cooler 30, so that the refrigerator outlet pressure is made less than the critical pressure, and the liquid refrigerant can be sent to a showcase 3. As a result, the specific enthalpy of the refrigerant at the inlet side of main diaphragm means 41 of the showcase 3 can be reduced, and thereby, the cooling effect can be increased.

A refrigeration system includes: a compressor arrangement for compressing gaseous refrigerant from a first pressure to a second pressure, wherein the second pressure comprises a condensing pressure; a plurality of condenser evaporator systems, wherein each condenser evaporator system comprises: a condenser for receiving gaseous refrigerant at a condensing pressure and condensing the refrigerant to a liquid refrigerant; a controlled pressure receiver for holding the liquid refrigerant from the condenser; and an evaporator for evaporating liquid refrigerant from the controlled pressure receiver to form gaseous refrigerant; a first gaseous refrigerant feed line for feeding the gaseous refrigerant at the second pressure from the compressor arrangement to the plurality of condenser evaporator systems; and a second gaseous refrigerant feed line for feeding gaseous refrigerant from the plurality of condenser evaporator systems to the compressor arrangement.