The effect of operating conditions on the performance of zeolite/water adsorption cooling systems

A numerical investigation of the effect of operating conditions on the thermal performance (coefficient of performance and specific cooling power) of an adsorption cooling system based on the Zeolite 13X/water working pair is presented in this paper. Both heat and mass transfer limitations are taken into account in the numerical model. Darcy's law and the linear driving force (LDF) model are used to describe the mass transfer limitation between the particles and within the particle, respectively. In this study, the effect of operating conditions such as adsorption temperature (Ta), generation temperature (Tg), condensing temperature (Tc), evaporating temperature (Te), the driven temperature of heat exchange fluid (Th,in) and the velocity of heat exchange fluid, on system performance were investigated. The results show that Ta, Tg, Tc and Te have significant effects on the system performance. For a given set of operating conditions, Ta and Tg possess optimal values based on the system performance. The driven temperature, Th,in was found to have negligible effect on the coefficient of performance although the optimal cooling power increases with Th,in. The cycle time decreases with an increase in fluid velocity, but this effect will be reduced for a high value of fluid velocity. The results of the numerical investigation will provide useful inputs to the development of an experimental adsorption cooling facility in the School of Mechanical and Production Engineering at the Nanyang Technological University.