Performance Analysis of Adsorption Refrigeration System

Abstract

The demand for refrigeration and air-conditioning is increasing day by day due to global warming. Conventional methods of refrigeration require CFC, HCFC and CFC as refrigerants, but, the emission of these refrigerants play a significant role in ozone layer depletion enhancing the global warming. The direct electrical energy utilization to a lage extent is also a drawback of conventional refrigeration methods. So the demand of environment friendly and energy efficient technology for refrigeration and air conditioning is increasing. Adsorption cooling has gained attention as a novel technology. It has the advantages of being environment friendly, having zero ozone depletion potential (ODP) as well as zero global warming potential (GWP) as natural refrigerants such as water and ammonia can be used as refrigerants, and can be driven by low grade energy such as solar energy and waste heat. In this thesis performance analysis of a single bed adsorption system is performed using activated carbon ammonia as working pair. A simple model base on thermodynamic cycle of the adsorption refrigeration process is used for the analyzing cooling capacity (MJ/m3) and the coefficient of performance (COP) of the system. The model is based on the Dubinin - Astakhov (D-A) equation which correlates adsorption or desorption per unit mass of adsorbent to the temperature of the adsorbent. A code is developed for the model analysis. Driving temperature is varied from 350 K to 550 K (typical range of temperature obtainable from automotive exhaust gas). Activated carbon adsorbents investigated are: 208C, SRD1352/2, SRD1352/3 and SRD06040. Best performance is obtained for SRD1352/2 type activated carbon for cooling production of 217 MJ m-3 with a COP of 0.7 and driving temperature 410 K.