NUMERICAL ANALYSIS OF MULTI-BED ACTIVATED CARBON/METHANOL ADSORPTION REFRIGERATION SYSTEM WITH ALLOWANCE FOR DYNAMIC PRESSURE VARIATIONS

摘要

The performance of a multi-bed (4 beds) adsorption refrigeration system having an activated charcoal-methanol pair was investigated using a numerical model. The model appropriately accounts for heat transfer, mass transfer, and thermodynamic behaviours, and distinguishes itself from similar studies in that it allows for pressure variation during desorption and adsorption stages. During operation, methanol desorbs and adsorbs simultaneously in two separate adsorber beds, while two other beds are heated and cooled in preparation for desorption and adsorption, respectively. A control strategy was investigated whereby bed switching is automated as a response to changes in bed pressures and water flow rates. The results were analysed to determine the effects of key operational parameters including water flow rate, heat source temperature and evaporator temperature on the performance indicators of coefficient of performance (COP) and specific cooling power (SCP).