Long-term performance analysis of a hybrid indirect evaporative cooling-mechanical vapor compression system in Saudi Arabia

Air-conditioning is the major source of energy consumption in the Middle East region, accounting for more than 50% of the peak load. Indirect evaporative cooling (IEC) is a promising technology that can significantly reduce the energy consumption of air conditioning, but its performance degrades severely when air humidity is high. To overcome this limitation, the hybridization of indirect evaporative cooling and mechanical vapor compression (MVC) has been proposed, which uses IEC to pre-cool the outdoor air and then further processes the air to desired temperature and humidity. The hybrid IEC-MVC process possesses the merits of the two, i.e., low energy consumption and capability of humidity control. Herein, we evaluate the energy-saving potential of the hybrid system under the climatic conditions of Saudi Arabia. Based on a validated mathematical model, the annual cooling performance and energy consumption of hybrid IEC-MVC configuration is predicted under the climatic conditions of 14 major cities in Saudi Arabia, and results are compared with that of standalone MVC. Moreover, the water consumption of the IEC and potential amount of recoverable water are estimated. Results reveal that IEC handles more than 50% of the annual cooling load and reduces energy consumption by up to 40%. Moreover, in humid areas, the condensate recovered from MVC is able to replenish more than 70% of the water consumed by IEC.