Effect of Climatic Governing Parameters on the Performance of Solar Adsorption Refrigeration System

Abstract

Solar energy is a renewable resource, clean and ecologically friendly. Solar thermal energy is attractive alternative energy to drive the adsorption of refrigeration machines. This work presents a numerical investigation of the effect of climatic governing parameters such as ambient temperature and component temperatures on the performance of solar adsorption refrigeration systems using methanol/activated charcoal pairs.

Activated carbon as adsorbent and methanol as a refrigerant is selected. Some predictive empirical equations accounting for heat balance in the solar collector components, instantaneous heat and mass transfer in adsorbent bed, and performance parameters were presented. Interactive C++ programming was developed to carry out the parametric study of some climatic factors such as ambient temperature and solar radiation intensity with aperture width of 0.14 m, collector length of 2.1m on the system performance. The effect of ambient temperature and component temperatures with aperture width, collector length, on specific cooling power (SCP), refrigeration cycle COP (COP_cycle), and solar coefficient of performance (COPs) are being investigated. The results are presented in form of profiles such as pressure developed in the generator, specific cooling power and system coefficient of performance profiles, under varying weather conditions and ambient temperature, operating conditions of evaporating temperature, T_ev = 0 ^oC, condensing temperature, T_con = 30 ^oC and desorption temperature of 100 ^oC,

The influences of operating and design parameters on the system performance are significant. The system performance shows no appreciable changes with varying condenser temperature with significant effect with varying evaporation and desorption temperature. It is shown clearly that for different desorption temperatures below 120 ^oC there is an appreciable effect on the system performance parameters. The study has revealed the system attains a promising performance of the adsorption refrigeration system using AC / methanol pair driven by solar energy.

Keywords: Adsorption; Refrigeration; Activated carbon/methanol; Simulation