Theoretical study of the performance of an ammonia/water absorption-resorption refrigeration system.

Ammonia is a well-known natural refrigerant which has been widely used in refrigeration technology due to its favorable thermodynamic properties. In this paper, an absorptionresorption refrigeration system is studied. The main advantages of an absorption-resorption system compared to commonly used absorption refrigeration systems are the lower pressure levels and the use of lower temperatures at the desorber and the resorber. Thus, resorption technology opens up new possibilities for using cheaper assembly materials, for example polymeric heat exchangers, due to the lower working pressures. In this work, the modeling of an absorption-resorption refrigeration system using Engineering Equation Solver (EES) is used to analyze the performance of the cycle working at moderated pressure levels. The study was divided in two parts: First, taking into account only the internal variables of the cycle, the influence of the pressure and temperatures on the cycle performance (composition of the solution circuits, COP and cooling capacity) has been studied. Secondly, it has been carried out a preliminary comparison between the calculated and experimental results obtained in an ammonia/water absorption-resorption refrigeration chiller, which was set up at TU Dresden by Makatec GmbH. For this second task, a model has been developed that takes the external streams into account.