Improving the Performance of the Air Conditioning Unit in Different Locations of a City Bus and Lightening the Air Ducts

Özcan O., Demirtaş S., Ylldlz A. E., Coşkun A.

SAE Automotive Technical Papers, WONLYAUTO 2022, Pennsylvania, United States Of America, 01 January 2022 identifier

  • Publication Type: Conference Paper / Full Text
  • Doi Number: 10.4271/2022-01-5044
  • City: Pennsylvania
  • Country: United States Of America
  • Keywords: Air conditioning unit, Air duct, CFD, Fan boundary condition, HVAC, Lightweighting
  • Istanbul Technical University Affiliated: Yes


© The focus of this study is to validate vehicle test results of the air conditioning (AC) unit in a city bus and perform a comparative computational fluid dynamics (CFD) analysis on homogenizing the cabin air distribution in different AC unit locations on the rooftop. To validate CFD practical results, a vehicle test was performed outdoor during the AC unit works. Obtained test results based on airflow rate inside AC unit and also measured velocity values on the front cabin of air duct were validated without completely modeling the whole AC unit and indoor cabin via CFD. With this simplified method, it is thought that this approach can give an idea for new prototype air duct designs in relevant industries. Another advantage to this approach is that it avoids high mesh density near the radial fans (blowers) placed on the AC unit. Foam placed in air ducts as insulation and air blockage material is also optimized for air distribution in the indoor cabin. In conclusion, several foams and air duct designs are reviewed, and a design that represents the most appropriate homogenous air distribution and lightweight air duct is proposed.