Provided is a supercritical fluid chromatography system, and components comprising such a system, including one or more of a supercritical fluid chiller, a supercritical fluid pressure-equalizing vessel, and a supercritical fluid cyclonic separator. The supercritical fluid chiller and the use of the chiller allow efficient and consistent pumping of liquid-phase gases employing off-the-shelf HPLC pumps in the supercritical chromatography system using liquid-phase gas mobile phase. The pressure equalizing vessel allows the use of off the shelf HPLC column cartridges in the supercritical chromatography system. The cyclonic separator efficiently and effectively allows for separation of sample molecules from a liquid phase or gas phase stream of a supercritical fluid.

Embodiments as disclosed herein are directed to a heat pump that employs at least two different refrigerants, each of which is optimized for either a cooling operation mode or a heating operation mode. The embodiments as disclosed herein can help increase the capacity and/or efficiency of a heat pump in both the cooling operation mode and the heating operation mode. In addition, the embodiments as disclosed herein may also eliminate the need for a ground source in a relatively low ambient temperature environment.

Disclosed herein is a method for producing heating in a high temperature heat pump comprising condensing a vapor working fluid comprising Z-1,1,1,4,4,4-hexafluoro-2-butene, in a condenser, thereby producing a liquid working fluid. Also disclosed herein is a method of raising the maximum feasible condenser operating temperature in a high temperature heat pump apparatus comprising charging the high temperature heat pump with a working fluid comprising Z-1,1,1,4,4,4-hexafluoro-2-butene. Also disclosed herein is a composition comprising: (a) Z-1,1,1,4,4,4-hexafluoro-2-butene; (b) 2-chloropropane; and (c) at least one lubricant suitable for use at a temperature of at least about 150° C.; is wherein the 2-chloropropane is present in an amount effective to form an azeotrope or azeotrope-like combination with the Z-1,1,1,4,4,4-hexafluoro-2-butene. Also disclosed herein is a high temperature heat pump apparatus containing a working fluid comprising Z-1,1,1,4,4,4-hexafluoro-2-butene.

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 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 modular refrigeration system includes a refrigeration loop having a compressor, a condenser, an expansion assembly, and a chiller interconnected by a first piping loop cycling hydrocarbon refrigerant. A high side cooling loop includes a first heat exchanger and a first pump interconnected with the condenser by a second piping loop cycling a cooling fluid, the cooling fluid exchanges heat with the hydrocarbon refrigerant at the condenser. A low side cooling loop includes a second heat exchanger and a second pump interconnected with the chiller by a third piping loop cycling a chilled fluid, the chilled fluid exchanges heat with the hydrocarbon refrigerant at the chiller. A space supports the second heat exchanger and is configured to be maintained within a predetermined temperature range, wherein the total charge of hydrocarbon refrigerant associated with the space does not exceed 150 grams.

Cooling systems and methods with high efficiency and of compact design are disclosed. In an aspect, cooling systems and methods are disclosed that are capable of generating thermal energy that powers at least some of the components of the disclosed cooling systems. Such cooling systems and methods may utilize heat energy transfers into and out of an internal fluid that undergoes substantial changes in pressure states such that the changes in pressure states of the internal fluid generate mechanical power that may be converted into usable energy by other portions of the system. Such cooling systems and methods may be capable of removing unwanted heat from building interiors, various pieces of machinery, electrical components, and spaces proximal to industrial and commercial processes.

A system includes a flash tank, a first load, a second load, a first compressor, a second compressor, a first valve, and a second valve. The flash tank stores a refrigerant. The first and second loads use the refrigerant to cool first and second spaces. The first compressor compresses the refrigerant from the first load during a first mode of operation and a flash gas from the flash tank during a second mode of operation. The second compressor compresses a mixture of the refrigerant from the first and second loads during the first mode of operation. The first valve directs the flash gas from the flash tank to the first compressor during the second mode of operation. The second valve directs the compressed flash gas from the first compressor to the first load during the second mode of operation to defrost the first load.

A system includes a flash tank, a first load, a second load, a first compressor, a second compressor, a first valve, and a second valve. The flash tank stores a refrigerant. The first and second loads use the refrigerant to cool first and second spaces. The first compressor compresses the refrigerant from the first load during a first mode of operation and a flash gas from the flash tank during a second mode of operation. The second compressor compresses a mixture of the refrigerant from the first and second loads during the first mode of operation. The first valve directs the flash gas from the flash tank to the first compressor during the second mode of operation. The second valve directs the compressed flash gas from the first compressor to the first load during the second mode of operation to defrost the first load.

A thermal management system includes at least one vapor compression system (VCS) that is configured to cool portions of the vehicle. The VCS circulates a fluid therethrough to cool the portions of the vehicle through heat exchange. At least one reverse air cycle machine (RACM) couples to VCS through a first heat exchanger. The RACM is configured to receive ram air. The RACM expands the ram air. Heat from the fluid circulating through the VCS is transferred to the expanded ram air through the first heat exchanger.