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In recent years, it has been observed that room air conditioners require considerable amounts of electricity. In this study, the annual performance and applicability of a hybrid air conditioner combining a fresh air ventilator and direct evaporative cooling water spray system were evaluated. The direct ventilation temperature degree-hour (TDH), evaporative cooling enthalpy degree-hour (IDH), and hybrid temperature degree-hour (TIDH) were defined to represent the applicability of natural energy. Meteorological data in China was used to determine the natural source utilization potential for direct ventilation and evaporative cooling. An applicability analysis was conducted in 334 cities in China. To further analyze the energy-saving potential, a simulation model was established and verified for the hybrid air conditioner based on laboratory tests. The operation periods with different work modes, energy-saving rates, and energy efficiency values were considered for three typical cities, i.e., Nanjing, Beijing, and Lanzhou, representing wet, semi-wet, dry, and semi-dry zones, respectively. Considering the extra energy consumption of the ventilator, the total energy consumption was reduced in these cities by 6.4%, 22.6%, and 50.2%, respectively, and the system seasonal energy efficiency ratios (SEERs) improved by 6.9%, 29.3%, and 98.9%, respectively. Finally, the energy-saving potential, operation ratios, and absolute energy-saving values were calculated and analyzed for 31 provinces in different working zones. The results indicate that the proposed system has the best applicability and energy-saving potential in northern China. • A simulation model was established for a hybrid air conditioner. • An applicability analysis was conducted in 334 Chinese cities. • Energy consumption was reduced by 6.4, 22.6, and 50.2% in three typical cities. • The energy-saving potential in 31 provinces was calculated and analyzed. [ABSTRACT FROM AUTHOR]

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. • A hybrid air conditioner combining ventilator and evaporative cooling is proposed. • Typical day and SEER tests were carried out under three typical conditions. • Operation period of mechanical refrigeration decreased from 32.5% to 56.1%. • Total cooling capacity of mechanical refrigeration decreased from 27.9% to 69.1%. • SEER improved by 12.3%, 38.5% and 221.9% respectively. [ABSTRACT FROM AUTHOR]