Study and control of the optimal generation temperature in NH3-H2O absorption refrigeration systems

This paper presents the results of a study on the optimal generator temperature (OGT) in single stage NH3-H2O Absorption Refrigeration Systems (AARS). It is well known that the generation temperature affects the AARS's Coefficient of Performance (COP) and that there is a temperature value, called optimal generation temperature, for which the COP is maximum. Therefore, to develop new control strategies designed to maintain the optimal temperature in the system generator, it is necessary to study the dependency of this temperature on thermal operating conditions and system design parameters. One such type of study has been carried out here by means of a parametric analysis, using a simple model implemented in a computer program. Based on the results obtained a novel control system that works on two separated control-loops has been designed. The proposed control system maintains a constant temperature in the space to refrigerate as well as the optimal temperature in the system generator. (C) 2000 Elsevier Science Ltd. All rights reserved.