Thermodynamic and economic analysis of the performance of a direct evaporative cooler working under extreme summer weather conditions

摘要

Riyadh is a desert region characterized by large daily and seasonal ambient temperature variations. Air cooling using mechanical vapor compression requires high energy rates resulting in negative environmental impacts. The use of non-conventional cooling methods such as evaporative cooling is attractive and needs further investigations particularly in such critical weather conditions. This paper deals with the analysis of the performance of a direct evaporative cooling in hot and arid weather conditions. Theoretical models using heat and mass transfer, exergy and cost analysis are first developed and presented. Such models have been systematically validated using available experimental and theoretical results from previous studies. The second part of the work concerns the analysis of the performance of a direct evaporative cooler under a metropolitan central Arabian Peninsula (Riyadh, KSA) weather conditions using average hourly temperature and relative humidity of the month of July. The optimum operating parameters of the cooler have been then selected. The analysis shows that the effect of the cooler effectiveness on the exergy efficiency is not significant. The suitable value of the effectiveness of the evaporative cooler working under summer weather of the studied location is found to be between 0.7-0.8. Such a value achieves comfortable conditions at low cost.