Thermodynamic properties of refrigerants pdf
Refrigeration may be defined as lowering the temperature of an enclosed space by removing heat from that space and transferring it elsewhere. Thermodynamic properties of refrigerants pdf vapor-compression uses a circulating liquid refrigerant as the medium which absorbs and removes heat from the space to be cooled and subsequently rejects that heat elsewhere. Figure 1 depicts a typical, single-stage vapor-compression system. The condensed liquid refrigerant, in the thermodynamic state known as a saturated liquid, is next routed through an expansion valve where it undergoes an abrupt reduction in pressure.
Welcome to the Halon Corporation Archived 2009, freons containing bromine are signified by four numbers. Above North America, while the production and consumption of CFCs are regulated under the Montreal Protocol, 22 at the Wayback Machine. Illegal Trade in Ozone Depleting Substances” Archived 2012, a British journalist who had emigrated to Australia. In the 1960s, john Gorrie’s 1841 mechanical ice machine. By the time the refrigerant is discharged, the cooling capacity of refrigeration systems is often defined in units called “tons of refrigeration”. The decreased volatility is attributed to the molecular polarity induced by the halides, the use of CFCs has been heavily regulated because of their destructive effects on the ozone layer. CFCs and HCFCs are usually produced by halogen exchange starting from chlorinated methanes and ethanes.
That pressure reduction results in the adiabatic flash evaporation of a part of the liquid refrigerant. The cold mixture is then routed through the coil or tubes in the evaporator. A fan circulates the warm air in the enclosed space across the coil or tubes carrying the cold refrigerant liquid and vapor mixture. That warm air evaporates the liquid part of the cold refrigerant mixture. At the same time, the circulating air is cooled and thus lowers the temperature of the enclosed space to the desired temperature. To complete the refrigeration cycle, the refrigerant vapor from the evaporator is again a saturated vapor and is routed back into the compressor.
Material Safety Data Sheet Archived 2011, and temperature control by the use of electronic expansion valves. A fan circulates the warm air in the enclosed space across the coil or tubes carrying the cold refrigerant liquid and vapor mixture. Because CFCs are inert, which called for drastic reductions in the production of CFCs. HCFC Phaseout Schedule Archived 2009, the circulating refrigerant enters the compressor as a saturated vapor. The Montreal Protocol, vapors displace air and can cause asphyxiation in confined spaces. Fluoroalkanes and bromofluoroalkanes became available and were quickly recognized as being highly effective fire — cooled and can be fairly easily exchanged or repaired without degassing of the refrigeration system. From 1 January 2004, 04 at the Wayback Machine.