There are few situations more uncomfortable than sitting on a public bus in a hot, dry climate, especially if the bus has no air conditioning. However, a new study published in the International Journal of Heavy Vehicle Systems suggests that passengers could be comfortable without using extra fuel for air conditioning after all.
According to Sunil Kale from the Department of Mechanical Engineering at the Indian Institute of Technology, the majority of passenger trips are taken in open window buses and for cost reasons, particularly in the developing world, only a small fraction of inter-city vehicles are air conditioned.
Instead opened windows are supposed to improve airflow and keep the passengers cool – but the cooling effect of open side windows is generally inadequate for comfort in the hottest parts of the world in a crowded bus.
So Kale’s team has carried out an aerodynamic study of fluid flow in a 1:25 model. It suggests that a few modifications to the conventional design could boost cooling airflow with none of the cost or energy requirements of an air conditioning system.
According to its findings, it is the turbulent flow into a standard bus that does not allow air into all areas. However, with a wide vent at the front and rear of a bus, air can be drawn into the vehicle at a much better rate and a similar boost can be obtained with adjustable roof vents.
These modifications, the team believes, will allow cooling air to increase the comfort of the bus from a mere 11 per cent to more than 50 per cent. This allows all passengers to experience some airflow as well as providing an overall reduction in drag.
air conditioning is not air ventilation, common 🙂