[sustran] Improving bus design cools passengers, saves fuel

Eric Britton eric.britton at ecoplan.org
Tue Jul 21 16:13:23 JST 2009


I thought this was interesting. Any comments, further background?

 

Eric Britton

 

Contact: Sunil Kale
srk at mech.iitd.ac.in
Inderscience <http://www.inderscience.com>  Publishers 


Slotted buses keep passengers cool


Improving bus design cools passengers, saves fuel


A simple redesign of public buses used in hot and dry climates could make
passengers more comfortable without the need to use extra fuel running air
conditioning, according to a study published in the International Journal of
Heavy Vehicle Systems.

Sunil Kale of the Department of Mechanical Engineering, at the Indian
Institute of Technology Delhi, India, and colleagues point out that the
majority of passenger trips are taken in open window buses.

Worldwide, buses are the principal means of commuting within and between
cities, the researchers explain. For cost reasons, particularly in the
developing world, only a small fraction (less than 5%) of inter-city
vehicles are air-conditioned. They add that air-conditioning is not a
commercially or environmentally viable alternative to simply opening the
side windows and even the doors.

Opened windows are supposed to improve airflow and keep passengers cool
while the bus moves. However, the cooling effect of open side windows is
inadequate for comfort in the hottest parts of the world on a crowded bus.

Kale's team has now carried out an aerodynamic study of fluid flow in a 1:25
model. Their findings suggest that a few simple modifications to
conventional design could significantly boost cooling airflow with none of
the cost or energy requirements of an air- conditioning system.

The turbulent flow into a standard bus does not allow air into all areas.
Passengers sitting near or standing in the aisle do not receive any
ventilation, while those in the front seats receive airflow from the rear.
The team has found that a wide vent at the front and rear of a bus will draw
air into the bus at a much better rate than side windows. A similar boost
can be obtained with adjustable roof vents.

These modifications would allow cooling air to increase the comfort zone of
the bus from a mere 11% of the interior volume to more than 50%. This means
that all passengers will experience some cooling airflow. In addition to
improved comfort there is an overall reduction in drag. Some of this drag
reduction could be sacrificed to provide grills and filters to prevent the
influx of insects and dust. Optionally a passive evaporative cooling system
could be incorporated into the vents to cool the incoming air and further
boost the comfort inside the bus.

"In a long-term policy perspective of sustainable transport, buses form an
important mode of transport that needs to be strengthened," the researchers
say, "Besides improving fuel economy, passenger comfort is a major issue
with such buses especially in tropical climates."

###

"Aerodynamics of a bus with open windows" in International Journal of Heavy
Vehicle Systems, 2009, 16, 459-488 

 

 

 

With all good wishes,

 

Eric Britton 

Managing Editor

 

|  <mailto:editor at worldstreets.org> editor at worldstreets.org |
<http://www.worldstreets.org/> World Streets | Paris  | +331 4326 1323 |
Skype newmobility

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://list.jca.apc.org/public/sustran-discuss/attachments/20090721/7a8239c2/attachment.html


More information about the Sustran-discuss mailing list