Sunday, 11 December 2011

Absorption refrigerator

An assimilation refrigerator is a refrigerator that uses a calefaction antecedent (e.g., solar, kerosene-fueled flame, decay calefaction from factories or commune heating systems) to accommodate the activity bare to drive the cooling system. Assimilation refrigerators are a accepted another to approved compressor refrigerators area electricity is unreliable, costly, or unavailable, area babble from the compressor is problematic, or area surplus calefaction is accessible (e.g., from agent exhausts or automated processes, or from solar plants).

For example, assimilation refrigerators powered by calefaction from the agitation of abounding petroleum gas are generally acclimated for aliment accumulator in recreational vehicles. Absorptive algidity can additionally be acclimated to aerate barrio application the decay calefaction from a gas agent or baptize heater. This use is actual efficient, aback the gas agent produces electricity, hot baptize and air-conditioning (called trigeneration).

Both assimilation and compressor refrigerators use a refrigerant with a actual low baking point (less than 0 °F/−18 °C). In both types, aback this refrigerant evaporates (boils), it takes some calefaction abroad with it, accouterment the cooling effect. The capital aberration amid the two types is the way the refrigerant is afflicted from a gas aback into a aqueous so that the aeon can repeat. An assimilation refrigerator changes the gas aback into a aqueous application a altered adjustment that needs alone heat, and has no affective parts1. The added aberration amid the two types is the refrigerant used. Compressor refrigerators about use an HCFC or HFC, while assimilation refrigerators about use ammonia or water.

The accepted for the assimilation refrigerator is accustomed by the ANSI/AHRI accepted 560-2000

Simple salt and water system

A simple assimilation algidity arrangement accepted in ample bartering plants uses a band-aid of lithium boiler alkali and water. Baptize beneath low burden is evaporated from the coils that are actuality chilled. The baptize is captivated by a lithium bromide/water solution. The baptize is apprenticed off the lithium boiler band-aid application heat.3

Water spray absorption refrigeration

Another variant, depicted to the right, uses air, water, and a alkali baptize solution. The assimilation of warm, clammy air is anesthetized through a sprayed band-aid of alkali water. The aerosol lowers the clamminess but does not decidedly change the temperature. The beneath humid, balmy air is again anesthetized through an evaporative cooler, consisting of a aerosol of beginning water, which cools and re-humidifies the air. Clamminess is removed from the cooled air with addition aerosol of alkali solution, accouterment the aperture of cool, dry air.

The alkali band-aid is regenerated by heating it beneath low pressure, causing baptize to evaporate. The baptize evaporated from the alkali band-aid is re-condensed, and rerouted aback to the evaporative cooler

Single pressure absorption refrigeration

A single-pressure assimilation refrigerator uses three substances: ammonia, hydrogen gas, and water. At accepted atmospheric conditions, ammonia is a gas with a baking point of -33°C, but a single-pressure assimilation refrigerator is pressurised to the point area the ammonia is a liquid. The aeon is closed, with all hydrogen, baptize and ammonia calm and endlessly reused.

The cooling aeon starts with abounding ammonia entering the evaporator at allowance temperature. The ammonia is alloyed in the evaporator with hydrogen. The fractional burden of the hydrogen is acclimated to adapt the absolute pressure, which in about-face regulates the vapour burden and appropriately the baking point of the ammonia. The ammonia boils in the evaporator, accouterment the cooling required.

The abutting three accomplish abide to abstracted the aerial ammonia and the hydrogen. First, in the absorber, the admixture of gasses enters the basal of an acclivous alternation of tubes, into which baptize is added at the top. The ammonia dissolves in the water, bearing a admixture of ammonia band-aid and hydrogen. The hydrogen is calm at the top of the absorber, with the ammonia band-aid calm at the bottom.

The additional footfall is to abstracted the ammonia and water. In the generator, calefaction is activated to the solution, to distill the ammonia from the water. Some baptize charcoal with the ammonia, in the anatomy of vapour and bubbles. This is broiled in the final break step, alleged the separator, by casual it through an acclivous alternation of askance pipes with accessory obstacles to pop the bubbles, acceptance the calm baptize to cesspool aback to the generator.

Finally the authentic ammonia gas enters the condenser. In this calefaction exchanger, the hot ammonia gas is cooled to allowance temperature and appropriately condenses to a liquid, acceptance the aeon to restart