Experimental performance analysis of hybrid air conditioner in cooling season

In this study, a hybrid air conditioner was proposed and investigated, based on combining a fresh air ventilator and direct evaporative cooling water spray system. Relative to a previously developed air conditioner using fresh air, the proposed air conditioner could be controlled more efficiently controlled through control strategies based on the outdoor environment. In this study, four zones with different operation strategies were considered, including direct ventilation (Zone 1), evaporative cooling ventilation (Zone 2), high efficiency direct ventilation (Zone 3), and off ventilation (Zone 4). A 1.5-HP room air conditioner was integrated with a ventilator, and the design principle and ventilator selection was illustrated. To compare the performances of conventional and hybrid air conditioners, a laboratory was used to simulate a typical day with an ambient environment and indoor cooling loads. One day at the beginning of the cooling season in three typical cities (Nanjing, Beijing, and Lanzhou, representing wet, semi-wet, and semi-dry/dry zones, respectively) were selected to conduct the field tests. The results show that the hybrid air conditioner exhibits high energy efficiency and energy-saving potential. Compared with conventional air conditioners, the total cooling capacity shows decreases ranging from 27.9% to 69.1% for the three cities. And the seasonal energy efficiency ratio test shows improvements of 12.3%, 38.5% and 221.9% in Nanjing, Beijing, and Lanzhou, respectively, indicating high operation efficiency in the cooling season.

Automated summary

A hybrid air conditioner combining a fresh air ventilator and direct evaporative cooling water spray system was proposed and investigated in this study. The results showed that the hybrid air conditioner exhibited high energy efficiency and energy-saving potential compared to conventional air conditioners through laboratory testing and field verification in three different cities.