A heat transport system includes: a refrigerant circuit that seals therein a fluid including HFC-32 and/or HFO refrigerant as a refrigerant and that includes a refrigerant booster that boosts the refrigerant, an outdoor air heat exchanger that exchanges heat between the refrigerant and outdoor air, a medium heat exchanger that exchanges heat between the refrigerant and a heat transfer medium, and a refrigerant flow path switch that switches between a refrigerant radiation state and a refrigerant evaporation state; and a medium circuit that seals carbon dioxide therein as the heat transfer medium.

The invention provides a system for energy distribution that uses liquid carbon dioxide as a working fluid. Evaporation of the carbon dioxide provides cooling, and compression of the carbon dioxide gas back to the liquid state provides heat. The amount of heat transferred at both stages is sufficient to provide environmental heating and cooling. Waste thermal energy from a power plant, in the form of hot water, is fed into the system and used to drive the overall process. An underground thermal energy storage system is used to store energy flowing into the system that is in excess of the current demand.

A valve mechanism (14a, 14b, 63a, 63b, 90) includes: a valve body (80, 95); a first flow path (81) located opposite a distal end (80a, 95b) of the valve body (80, 95); a driver (85) configured to move the valve body (80, 95) to a first position where the distal end (80a, 95b) of the valve body (80, 95) closes the first flow path (81) and a second position where the distal end (80a, 95b) of the valve body (80) opens the first flow path (81); and a second flow path (82) configured to communicate with the first flow path (81) when the valve body (80) is at the second position. The high-pressure flow path (I1, I2, O2, O3, 48) causes the high-pressure refrigerant to always flow through the second flow path (82) and first flow path (81) of the valve mechanism (14a, 14b, 63a, 63b, 90) in this order.

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.

A refrigeration system includes a rotary pressure exchanger fluidly coupled to a low pressure branch and a high pressure branch. The rotary pressure exchanger is configured to receive the refrigerant at high pressure from the high pressure branch, to receive the refrigerant at low pressure from the low pressure branch, and to exchange pressure between the refrigerant at high pressure and the refrigerant at low pressure, and wherein a first exiting stream from the rotary pressure exchanger includes the refrigerant at high pressure in the supercritical state or the subcritical state and a second exiting stream from the rotary pressure exchanger includes the refrigerant at low pressure in the liquid state or the two-phase mixture of liquid and vapor.

A refrigeration system, in particular a transport refrigeration system, comprising: a refrigerant circuit, which in particular works using CO.sub.2 as the refrigerant and in which there is guided a total mass flow of the refrigerant; a high-pressure-side heat exchanger arranged in the refrigerant circuit and cooling refrigerant compressed to a high pressure; at least one cooling stage which expands the principal mass flow from the intermediate-pressure collector to a low pressure in at least one cooling expansion member and in so doing makes refrigeration capacity available at a low-pressure-side heat exchanger; and a refrigerant compressor unit which compresses the principal mass flow from a low pressure to a high pressure, wherein the refrigerant compressor unit has a first compressor stage for compressing, to a medium pressure, the refrigerant of the principal mass flow supplied at low pressure, and a second compressor stage for compressing, to a high pressure, the refrigerant of the principal mass flow that has been compressed to a medium pressure.

A system includes a high side heat exchanger, a flash tank, a first load, a second load, and a thermal storage tank. The high side heat exchanger is configured to remove heat from a refrigerant. The flash tank is configured to store the refrigerant from the high side heat exchanger and discharge a flash gas. The first load is configured to use the refrigerant from the flash tank to remove heat from a first space proximate to the first load. The second load is configured to use the refrigerant from the flash tank to remove heat from a second space proximate to the second load. The thermal storage tank is configured, when a power outage is determined to be occurring, to receive at least a portion of the flash gas from the flash tank, and remove heat from the flash gas.

A CO.sub.2 based refrigeration system and a method of operating the CO.sub.2 based refrigeration system. The system includes a condenser configured to transfer heat from a CO.sub.2 refrigerant of the refrigeration system to an air stream. The system also includes an indirect evaporative cooler arranged to cool an ambient air stream without changing its moisture content and to supply the cooled ambient air to the condenser to facilitate the transfer of heat from the CO.sub.2 refrigerant.

A cooling system includes a compressor configured to pressurize carbon dioxide to form pressurized carbon dioxide, a mixer configured to generate mixed refrigerant in which the pressurized carbon dioxide and solvent in a liquid state, a depressurization apparatus provided downstream from the mixer and configured to depressurize the mixed refrigerant, a separator configured to separate carbon dioxide in a gas state from the mixed refrigerant, a heat exchanger configured to exchange heat between the mixed refrigerant cooled through depressurization and a fluid to be cooled, and a second heat exchanger configured to cool the carbon dioxide or the mixed refrigerant using vaporized carbon dioxide or the mixed refrigerant.

A CO.sub.2 refrigeration system includes a plurality of compressors configured to circulate a CO.sub.2 refrigerant, a suction line configured to deliver the CO.sub.2 refrigerant to the compressors, an oil separator configured to separate oil from the CO.sub.2 refrigerant, and an oil return line configured to deliver the oil from the oil separator to the suction line. The oil mixes with the CO.sub.2 refrigerant in the suction line before reaching the compressors.