Analysis of Airflow Organization in Buses Air-Conditioned by Direct Evaporative Coolers

Considering the energy-saving advantages of the direct evaporative cooler (DEC) compared to the traditional air conditioning system (TAC), this study aims to indicate its ability to improve the thermal comfort and the indoor air quality of the bus compared to the bus air-conditioned by the traditional compressor system. Taking a bus in Lanzhou as the object, the numerical model and method were first verified by an experimental method. Then, numerical analyses were simultaneously carried out in both bus models, which were air-conditioned by TAC and DEC, respectively. The results showed that the thermal comfort of the bus air-conditioned by DEC is more satisfactory, and the indoor air quality is better. Additionally, the bus air-conditioned by DEC achieves a 43.7% improvement in the temperature efficiency and a 31.3% improvement in the ventilation efficiency compared to the bus air-conditioned by TAC. The conclusion will provide valuable insights into the application of DEC in buses in dry regions.