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Power Engineering and Rerigeration 515 Refrigeration & Air conitoning, , , , 2. Industrial processes., {@)_ Processing of food products., (b)_ Processing of farm crops., (6). Processing of textiles, printing work, photographic material etc., (d)_ Treatment of air for blast furnace., (©) Processing of tobacco, petroleum and other chemical products., 3. Providing comfortable environment., (@)_ Industrial air conditioning to suit product and process., (b)_Comfort air conditioning for cinema hall, shopping mall, banks, restaurants etc., , 5.13 APPLICATION TO DOMESTIC REFRIGERATOR, , ‘Applications :, , Itis common appliance used in domestic housing, vendor shop, hotels, offices, laboratories, chemists etc., , Capacity of Refrigerator :, , The capacity of refrigerator is expressed in litres. Litre represents a volume of cooling space available after closing, the door. The refrigerators are available in standard capacities of 65, 90, 165, 210, 240, 280, 300, 380, 420, $40 etc., , Refrigerant Used :, The refrigerant used is R-12 having chemical formula CCI,F. and chemical name Dichloro-difluro-methane now-adays itis replaced by 143a,, , Working Cycle, , ‘The domestic refrigerator works on Vapour compression cycle., , Important Components :, , 1. Hermetically sealed compressor :, , Hermetic compressor is mounted on bottom part behind compartment. The refrigerant vapours are sucked in, , compressor due to Suction drift and Gravity, , The gasket is provided to clamp the compressor to avoid vibration. For 165-litre refrigerator compressor motor, , of 1/4 to 1/6 HP is used., , Parameters for the Selection of Compression Used in Domestic Refrigerator :, , Following are the parameters used in domestic refrigerator, , (a) Compact size : As the space in residence is less, the appliance and in turn the compressor should have, compact size., , (b) Less weight : The compressor should be of less weight. The appliance in residence should be light, as it can, be moved in the house as per requirement., , (© Compatibility with eco-friendly refrigerant : Now-a-days the R-12 is not allowed for refrigeration. So the, domestic refrigerator compressor will be using the eco-friendly refrigerants like R-134., , (d)_ Sealed construction : For domestic use, the total refrigeration cycle must be sealed, so that no leakage will, be there. Itis difficult for frequent gas charging to system,, , (e) Low power loss and consumption : The appliance should be affordable for users. So, less power, consumption in necessary. Considering above points, it is advantageous to use hermetically sealed, ‘compressor in domestic refrigerator., , 2. Evaporator, Evaporator is generally made in box type construction. The refrigerant tubes are wrapped or brazed around, evaporator box. The evaporator is mounted on uppermost part of cabinet. The cooling effect is produced in, evaporator. The evaporator is provided with small holes on its bottom part to pass cold air from evaporator to, lower portion of reftigerator to produce cooling effect on lower portion of cabinet. In evaporator -ve, temperature is maintained to produce ice. The temperature on lower portion of cabinet is around 7 to 10°C.