Molla Engineering

 A hermetic or sealed compressor is one in which both compressor and motor are confined in a single outer welded steel shell. The motor and compressor are directly coupled on the same shaft, with the motor inside the refrigeration circuit. The compressor does exactly as its name says: it compresses the refrigerant. The compressor receives low pressure gas from the evaporator and converts it to  high pressure gas. As mentioned earlier, as the gas is compressed, the temperature rises. The hot refrigerant gas then flows to the condenser. A, refrigerator does not cool items by lowering their original temperatures; instead, an evaporating gas called a refrigerant draws heat away, leaving the surrounding area much colder. Refrigerators and air conditioners both  work on the principle of cooling through evaporation. Sealed or hermetic type, however has no need for the shaft seal. These are usually made in capacities from 0.4 kW to 110 kW. Sealed compressor for R-12 and for 2 are...

Method of compression of the refrigerant: one of the most important parts of any refrigeration cycle is the compression of the refrigerant since all the further operations depend on it. In the vapor compression refrigeration system the compression of the refrigerant is done by compressor which can be of reciprocating, rotating or centrifugal type. In the vapor absorption of the refrigerant by the absorbent. As the refrigerant is absorbed, it gets converted from the vapor state to liquid state so its volume reduces. Power consumption devices: In the vapor compression cycle the compressor is the major power consuming device while in the vapor absorption cycle the pump used for pumping refrigerant absorbent solution is the major power consuming device. The amount of power required: The compressor of the vapor compression cycle requires large quantities of power for its operation and it increases as the size of the refrigeration system increases. In case of the vapor absorption refrigerati...

 In a heat engine, heat is transferred from a higher temperature level called source to a lower temperature level called sink. A heat pump is similar to a refrigerator. The only point of difference between the two is of the operating temperatures. Difference between Refrigerator and Heat pumps Transfer of heat: Both the refrigerator and the heat pumps carry the heat from low temperature reservoir or the sink to the high temperature reservoir or source. The main purpose of the refrigerator is to chill or cool or freeze the substance, by maintaining very low temperature in the freezer. It absorbs the heat from the freezer or evaporator and throws it to the atmosphere which is at high temperature. The main purpose of the heat pump is to heat the room during winter seasons or when the atmospheric temperature is very low. It absorbs the heat from the atmosphere which is at low temperature and throws it to the room which is at high temperature and which is to be heated.     2. ...

  Two ways of Operating of Bell Coleman Cycle 1. Open air refrigeration cycle: When cooled air from the turbine enters the cabin and comes in physical contact with the occupants. It is not much in use because of moisture added to air in the cabin. 2. Closed air refrigeration cycle OR dense cycle: When cooled air from the turbine passes through the coil and a fan circulates and recirculates cabin air over it. The pressure of cooled air in such systems is much higher than in the open system. Because of high pressure volume is less and hence density of air is high. It is therefore also called a dense system.                      Dense Air Refrigeration System (Air Passes Through the Coils in the Cabin)                                                        Open Air Refrigeration System