Performance of a low- temperature NH 3H 2O absorption-refrigeration system

Abstract

Conventional absorption-refrigeration systems cannot produce temperatures below −20 °C. We have studied a two-stage NH 3H 2O absorption-refrigeration system, which may be used to produce refrigeration temperatures as low as −70 °C. This system operates at three pressure levels so that the heat released by the high-pressure condenser and by the medium-pressure absorber are rejected to the ambient, while heat released by the low-pressure absorber is received at the medium-pressure evaporator. A method and a corresponding computer code have been developed to simulate the operation of the proposed system. Employing this method, we predict for 10 °C ambient temperature that the theoretical coefficient of performance ranges from 20 to 65%, while the lowest temperatures range from −70 to −30 °C; the corresponding theoretical refrigeration load ranges from 300 to 1100 kJ/kg of refrigerant produced in the generator.