Search results
Results from the WOW.Com Content Network
Common absorption refrigerators use a refrigerant with a very low boiling point (less than −18 °C (0 °F)) just like compressor refrigerators.Compression refrigerators typically use an HCFC or HFC, while absorption refrigerators typically use ammonia or water and need at least a second fluid able to absorb the coolant, the absorbent, respectively water (for ammonia) or brine (for water).
Adsorption refrigeration has been extensively researched in recent years because the technology is often noiseless, non-corrosive and environmentally friendly. [5] The heat source for adsorption refrigeration can be fossil fuel, biomass fuel, nuclear fission, geothermal energy, waste heat, or solar thermal energy. [1]
A solar-powered refrigerator is a refrigerator which runs on energy directly provided by sun, and may include photovoltaic or solar thermal energy. Solar-powered refrigerators are able to keep perishable goods such as meat and dairy cool in hot climates and are used to keep much-needed vaccines at their appropriate temperature to avoid spoilage.
A National Aeronautics and Space Administration (NASA) sponsored report in 1976 surveyed solar energy system applications of air conditioning. Techniques discussed included both solar powered (absorption cycle and heat engine / Rankine cycle) and solar related (heat pump) along with an extensive bibliography of related literature. [2]
The performance of the absorption heat pump is indicated by the coefficient of performance (COP). The COP is the ratio of the removed (for refrigeration) or provided (for heating) heat to the energy input. At present, the maximum temperature of its output does not exceed 150 °C. The temperature rise ΔT is generally 30–50 °C.
The Einstein–Szilard or Einstein refrigerator is an absorption refrigerator which has no moving parts, operates at constant pressure, and requires only a heat source to operate. It was jointly invented in 1926 by Albert Einstein and his former student Leó Szilárd, who patented it in the U.S. on November 11, 1930 (U.S. patent 1,781,541).
The absorption cycle is similar to the compression cycle, but depends on the partial pressure of the refrigerant vapor. In the absorption system, the compressor is replaced by an absorber and a generator. The absorber dissolves the refrigerant in a suitable liquid (dilute solution) and therefore the dilute solution becomes a strong solution.
The most common refrigeration cycle is the vapor compression cycle, which models systems using refrigerants that change phase. The absorption refrigeration cycle is an alternative that absorbs the refrigerant in a liquid solution rather than evaporating it. Gas refrigeration cycles include the reversed Brayton cycle and the Hampson–Linde cycle.