Function of Absorption Refrigerator

Function of Absorption Refrigerator Points : function of absorption refrigerator system In this system we again use the same method of condensing and evaporating the refrigerant, on the bais of pressure difference. In compression system we produce the high pressure with the compressor and low pressure with expansion device but in it we do these with absorber and generator.

The absorption refrigeration we usually used NH₃ and H₂0, as the cooling effect of NH₃ is too much, and it gives quite a low temperature. A schematic drawing of this cycle’ is shown in the figure. The generator contains a solution of water and ammonia. Heat from the gas flame heats the solutions, and the ammonia is driven out in tube. A As it flow into the separator, any water present in the form of vapor is condensed and flow back through tube B into the absorber. The ammonia vapor flows up through tube C, to the condenser, where it s cooled and condensed into a liquid. The Liquid ammonia flows into the evaporator. The evaporator, tube D and a part of absorber, contains Hydrogen. Pressure throughout the system is approximately 15 bars.

From Dalton’s law we learned that in a mixture of gases, each one develops its own pressure so in this refrigerator the ammonia in the areas which includes Hydrogen gas will evaporate, and try the gas in the area the ammonia vapor pressure of l5bars. Since the Hydrogen represents a larger part of the gas in the area, the ammonia keeps on boiling or vaporization at its own pressure and absorbing heat. The vaporized ammonia and Hydrogen from the evaporator are at a low temperature, so by gravity these vapor flows down through tube D back to the absorber. In the absorber the water is relatively cool. It again absorbs the, ammonia and returns the cool water and the ammonia solution back to the generator.

The hydrogen which flows down to the absorber with the ammonia is not absorbed by water and is returned to the heat exchanger back to the ‘evaporator. The cycle operates continuously as long as refrigeration is needed. A thermostat which controls the burner is used to regulate the refrigerated space temperature.