It gives a low refrigeration effect. • Corrosive in nature. This refrigerant is then again absorbed by the weak solution in the absorber. Content Filtration 6. 2) Expansion valve or restriction: When the refrigerant passes through the expansion valve, its pressure and temperature reduces suddenly. In the vapor compression system, the compressor sucks the refrigerant from evaporator and compresses it to the high pressure. The current refrigeration system we use in domestic purpose is the vapor compression refrigeration system. – Vapor-absorption refrigeration. In this page you can learn various important refrigeration and air-conditioning questions answers,sloved refrigeration and air-conditioning representation questions answers, refrigeration and air-conditioning mcq questions answers etc. In the vapor compression cycle this refrigerant is sucked by the compressor, but in the vapor absorption cycle, this refrigerant flows to the absorber that acts as the suction part of the refrigeration cycle. • This system may be used in both the domestic and large industrial refrigerating plants. This system is often called “Munters Platen System”. c) Circulate the refrigerant. ADVANTAGES OF ABSORPTION SYSTEM OVER COMPRESSION SYSTEM • No moving part except pump-motor, which is comparatively smaller than compressor system. Absorption system performs a “smuggling” by chemically absorbing the gas in a liquid, carry it past the pressurizing stage and releasing the gas after attaining the pressure. • The vapour absorption system uses heat energy, instead of mechanical energy as in vapour compression systems, in order to change the conditions of the refrigerant. HVAC: Heating, Ventilation & Air-Conditioning. Pressurization of the gas is the main energy intensive process of a conventional refrigeration system, consuming the major part of the expense associated with it. The heat of absorption is also released in the absorber, which is removed by the external coolant. In vapour absorption refrigeration system, the temperature of the heat source plays an important role. The most commonly used fluids in the absorption system are water as absorbent and ammonia as refrigerant. Absorption-refrigeration Cycles. How Absoption Refrigeration System Works (Continued), Commercial Energy Usage: Learn about Emission Levels of Commercial Buildings, Time to Upgrade Your HVAC? Vapour absorption refrigeration systems using water-lithium bromide pair are extensively used in large capacity air conditioning systems. d) All of the above Ans. Unlike the mechanical-compression and absorption refrigeration systems discussed above, evaporative cooling doesn’t use the traditional refrigeration cycle. When the refrigerant entering in the absorber is absorbed by the absorbent its volume decreases, thus the compression of the refrigerant occurs. Ammonia was used for refrigeration in 1876, for the first time in a vapor compression machine by Carl Von Linde. At first the refrigerant are condensed in the condenser and it gets evaporated in the evaporator. Account Disable 12. Figure 36.35 for double-effect system is self-explanatory. Any refrigeration unit works with different components inline to each other in series. Developing the world to help mitigate poverty and climate change. Thus pump increases the pressure of the solution to about 10bar. Another major difference between the vapor compression and vapor absorption cycle is the method in which the energy input is given to the system. Thus the absorber and the generator replace the compressor in the vapor absorption cycle. vapour compression refrigeration systems. The basic difference between vapour compression and vapour absorption cycles will thus be to replace the compressor of the vapour compression cycle by a set of equipment which fulfils the objective discussed above. The commonly used basic cycles, in order of importance, are vapor-compression, absorption, steam-jet or steam-ejector, and air. For refrigeration system, To is the temperature at which heat is given to refrigerant (actually this is the heat abstracted from the body to be refrigerated) and the heat is rejected the atmosphere at Tk temperature. It is used to generate the vapour refrigerant in generator outlet. Comment * Related Questions on Refrigeration and Air Conditioning. It is an open types of cooler and forms an integral part of the generator, mounted on its top. Uses – It is widely used in large industrial and commercial refrigeration systems. Methods of refrigeration • Gas cycle - Air is most often the working fluid. This is can be steam, hot water or any other suitable source. . List of 7 Air Standard Cycles | Thermodynamics, Unconventional Machining Processes: AJM, EBM, LBM & PAM | Manufacturing, Material Properties: Alloying, Heat Treatment, Mechanical Working and Recrystallization, Design of Gating System | Casting | Manufacturing Science, Forming Process: Forming Operations of Materials | Manufacturing Science, Generative Manufacturing Process and its Types | Manufacturing Science. In fact, it can absorb vapor as quickly as a compressor. The absorption of the vapour is governed by Raoult’s law. 3 4. Since conventional absorption systems use liquids for … In this way, the refrigerant keeps on repeating the cycle. The high pressure and the high temperature refrigerant then enters the condenser, where it is cooled by the coolant, and it then enters the expansion valve and then finally into the evaporator where it produces the cooling effect. This type of refrigerator is also called “Three-fluids absorption system”. b) Reduce the partial pressure of refrigerant in evaporator. Figure 2 shows the vapour absorption refrigeration system using heating coil. Another heat exchanger is located between generator and absorber so that the strong aqua is heated up before going on to the analyzer and weak aqua is cooled before entering the absorber. Cylinder Liner Lubrication of Marine Two Stroke Crosshead Diesel Engines - Part 1, What are Gear Trains? Commonly used refrigerants for vapour compression chillers are chlorinated fluorocarbons (CFCs, also called Freons): R-11, R-12, R-21, R-22, R-134 and R-502. The heat can also be created by other sources like natural gas, kerosene, heater etc. • Vapour Absorption Refrigeration (VAR) (uses thermal energy). Vapours of refrigerants are generated in two stages as shown. dry ice. 36.33. The weak aqua-ammonia solution leaving the generator is at high pressure and the pressure in the absorber is the evaporator pressure which is less than the generator or condenser pressure, and hence a pressure reducing valve is provided in the weak solution line to the absorber. Carré's absorption refrigeration technique is an important vapor refrigeration technology, because it does not require a vapor compressor. The refrigerant gets condensed in the condenser and it gets evaporated in the evaporator. Thermal efficiency of the engine is given by-. The difference is that in adsorption refrigeration, the refrigerant or adsorbate vapour molecules adsorb onto the surface of a solid instead of dissolving into a liquid. While some people have viewed this method as environmentally harmful and inefficient, the cycle is still applicable in the industrial sphere. The refrigerants used in the vapor absorption system are ammonia, water and lithium bromide. 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