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ABSTRACT
The eighty-year-old single pressure absorption refrigeration system invented by Albert Einstein and Leo Szilard is attractive as it has no mechanical moving parts and can be driven by heat alone. The literature on the refrigeration system is scarce and only theoretical analyses are available. In this paper adversities of the primitive design and the operation of the refrigerator prototype are discussed. The prototype is able to achieve temperatures between 8°C (46.4°F) and 14°C (57.2°F). Five pairs of heat inputs between 53 W and III Warestudied. Cooling capacities decrease (from 34 W to l5 W) when the generator heat input increases, however, cooling capacities increase (from 17 W to 30 W) when the bubble pump heat input increases. The highest COP is 0.25 when the heat inputs to generator is 53 W and to bubblepump is 89 W. The ideal cooling capacity and COP are 40 W and 0.28, respectively.
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INTRODUCTION
The Einstein-Szilard refrigerator has caught increasing attention in the last few years across the globe (Jha 2008; TIME 2008; BBC 2010; Worms 2010). This refrigeration system was invented by Albert Einstein and Leo Szilard eight decades ago (Einstein and Szilard 1928, 1930). The unique relationship among the three working fluids, ammonia, butane and water, creates a partial pressure gradient for the refrigerant to evaporate and cool the surroundings. The system involves no moving parts, hence it has the potential to be reliable. However, the design has hitherto never been commercially produced and little information about the patent is available (Dannen 1997). From 1930to 1980, almost no work was done on this refrigeration system. Follín et al. (1980a, 1980b) intended to operate the refrigerator by using modest source temperatures (65°C [149°F] or below), which could be harvested from geothermal resources, solar thermal collectors, or cogeneration systems. In their study, the theoretical coefficient of performance (COP) of the system is 0.25 and 0.20, respectively. However, no further references or works pertaining to these studies are found.
An Einstein-Szilard refrigeration system without bubble pump was analyzed by Delano (1997) using a model derived from the principles of mass and energy conservation. The COP ofthe systemis 0.35. Later on, Delano (1998) applied the PatelTeja equation of state to assess the energy content...