The diffusion absorption refrigerator (DAR) is a hermetically sealed refrigeration system utilizing three working fluids-ammonia, water, and hydrogen. Despite its low efficiency, the DAR has many advantages: (1) free of moving parts, (2) driven by heat input, (3) silent during operation, and (4) ozone safe working fluids.; The purposes of the present study are to achieve higher performance and replace the flammable gas hydrogen with helium. First, baseline tests on a domestic DAR were performed. The experimental data were analyzed using a data reduction model (DRM). Then, the unit was modified using a more efficient generator with heat exchange (GWHX). The modified unit (MDAR) was tested and the results were compared to the baseline. Finally, the buoyancy effects on the rate of absorption were studied theoretically based on the experimental observation.; The experimental studies show that the cooling COP (coefficient of performance) of the MDAR increased by 50% compared to the baseline. The theoretical studies reveal that the buoyancy effects are significant in the DAR absorber which explains the inferior absorption with a helium charge. Based on this study, further modifications to the DAR are suggested.
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