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.

The position of the stabilizer container 7 in the circulation route is not limited. The stabilizer container 7 is preferably disposed between the evaporator and the condenser between which the refrigerant flows in the circulation route as a liquid refrigerant. Specifically, the stabilizer container 7 is preferably disposed between the outdoor heat exchanger 4 and the expansion mechanism 5 or between the indoor heat exchanger 6 and the expansion mechanism 5. During cooling, the outdoor heat exchanger 4 functions as a condenser and the indoor heat exchanger 6 functions as an evaporator. During heating, the outdoor heat exchanger 4 functions as an evaporator and the indoor heat exchanger 6 functions as a condenser. In either case of cooling or heating, the liquid refrigerant is present between the expansion mechanism 5 and the outdoor heat exchanger 4 or between the expansion mechanism 5 and the indoor heat exchanger 6 depending on the refrigerant circulation direction, and the stabilizer container 7 is located where the liquid refrigerant is present (i.e., between the expansion mechanism and whichever heat exchanger 4, 6 serves as the evaporator in the refrigerant circulation direction). Thus, as the liquid refrigerant passes through the stabilizer container 7, oxidation of the refrigerant can be efficiently prevented and acids in the circulation route can be efficiently scavenged.

Compositions, systems and methods for introducing lubricants, and additives, that are designed to work with environmentally friendly refrigerants into vehicle heat management systems including passenger compartment air conditioning (A/C) systems are disclosed. Methods for charging lubricants and specific additives using environmentally desirable (low GWP) refrigerant or refrigerant blend compositions into an environmentally friendly system, such as a system that uses HFO-1234yf, are also disclosed.

A hydrogen feed stream is introduced into a primary refrigeration system of a precooling system and cooling the hydrogen stream to a first precooling temperature. From there, the precooled hydrogen stream is then introduced to a secondary refrigeration system of the precooling system and cooling the precooled hydrogen stream to a second temperature. Next, the cooled hydrogen stream is then liquefied in the liquefaction system to produce liquid hydrogen.

An integrated industrial unit is provided, which can include: a nitrogen source configured to provide liquid nitrogen; a hydrogen source; a hydrogen liquefaction unit, wherein the hydrogen liquefaction unit comprises a precooling system, and a liquefaction system; and a liquid hydrogen storage tank, wherein the precooling system is configured to receive the gaseous hydrogen from the hydrogen source and cool the gaseous hydrogen to a temperature between 75 K and 100 K, wherein the precooling system comprises a primary refrigeration system and a secondary refrigeration system, wherein the liquefaction system is in fluid communication with the precooling system and is configured to liquefy the gaseous hydrogen received from the precooling system to produce liquid hydrogen, wherein the liquid hydrogen storage tank is in fluid communication with the liquefaction system and is configured to store the liquid hydrogen received from the liquefaction system.

A hydrogen feed stream is introduced into a primary refrigeration system of a precooling system and cooling the hydrogen stream to a first precooling temperature. From there, the precooled hydrogen stream is then introduced to a secondary refrigeration system of the precooling system and cooling the precooled hydrogen stream to a second temperature. Next, the cooled hydrogen stream is then liquefied in the liquefaction system to produce liquid hydrogen. The refrigeration is provided by expansion of a pressurized gaseous nitrogen stream and vaporization of a liquid nitrogen stream that is sourced from a nearby air separation unit.

A composition comprising: (i) 1,1-difluoroethene (vinylidene fluoride, R-1132a); (ii) carbon dioxide (CO.sub.2, R-744); (iii) pentafluoroethane (R-125); and (iv) one or more of trifluoromethane (R-23) and hexafluoroethane (R-116).

One aspect of the present invention is a refrigerating machine oil containing: a base oil containing an ester of an alcohol and a fatty acid; a compound represented by the following formula (1): ##STR00001##
wherein R.sup.1 and R.sup.2 each independently represent a monovalent hydrocarbon group, R.sup.3 represents a divalent hydrocarbon group, and R.sup.4 represents hydrogen atom or a monovalent hydrocarbon group, and the refrigerating machine oil having a kinematic viscosity at 40° C. of 10 mm.sup.2/s or less.

A bipolar plate having side ports is described for use with an electrochemical cell. A side port having a high aspect ratio will have an effect on the partial pressure of the reactant gasses and prevent high pressure drop of the working fluid transport to the electrodes. The membrane electrode assembly may have a high aspect ratio and the port opening may be on the long side of the bipolar plate. The electrochemical cell may be configured in an enclosure that is maintained at less than atmospheric pressure which further increases the need for low pressure drop fuel deliver to the electrodes, especially in electrochemical compressor applications.

The disclosure relates to a method and a device for providing zeotropic refrigerants in which the refrigerant is formed from a refrigerant blend of at least two components, the components being added to a container in the ratio of their respective mass fractions to the refrigerant, and the refrigerant blend being formed in the container, wherein the temperature and/or the pressure in the container is set by means of a control device such that the refrigerant is present exclusively in the gas phase or exclusively in the liquid phase.