Modeling, Refrigeration, Adsorption, Lumped parameter, COP
In this paper, we proposed a dynamic model for a two-bed adsorption refrigeration system. Different from most existing researches which assume saturation vaper pressure in each device, the proposed method models the pressure in each device by considering both the liquid and vaper content in the device. Therefore, it can be more accurate in describing the system response and more suitable for studying the system instrumentation. The components included in this system model are: adsorption bed, evaporator, condenser, expansion valve, and etc. Each device is modeled based on the energy and mass conservation. Furthermore, the adsorption phenomenon is modeled by the â€œFreundlich equation,â€ and â€œlinear driving force model.â€ The phase change of the refrigerant in evaporator and condenser is modeled by Hertz-Knudsen theory. In a case study, the pressure of the adsorption bed during the adsorption process is estimated to be 0.7kPa by the proposed model, while it was 1.6kPa by conventional method which assuming saturated vapor pressure. The coefficient-of-performance of the adsorption system is estimated to be 0.246 by this model, 0.36 by conventional method, and 0.28 by experimental data. The proposed model can estimate system performance more accurate than the conventional method. Moreover, the proposed model also inspire a new instrumentation strategy for the adsorption system, in which the system efficiency is improved and the pressure surge is avoided.