MiT on Doors and Efficiency

MiT has a new sustainability wiki with page analyzing doors. Apparently the average heat transfer per swing door passage is 78 Wh (267 BTU) which is the equivalent of:

• 1.3 hours of light from a desk lamp
• 4.3 hours of light from a compact fluorescent bulb
• Driving a car 306 feet
• Half a mile jog

And apparently using a revolving door is much more efficient:

On average 8x as much air is exhanged when a swing door is opened as opposed to a revolving door. That's 8x as much new air that needs to be heated or cooled and that's why using the revolving door is a great way to reduce energy requirements on campus. {snip} Our estimates show that if everyone used the revolving doors at E25 alone, MIT would save almost $7500 in natural gas amounting to nearly 15 tons of CO₂. And that’s just from two of the 29 revolving doors on campus!

More at their wiki

New Engine Promises Greater Efficiency
From MIT's Technology Review:

The gas-saving technology, called homogeneous charge compression ignition, or HCCI, uses a form of combustion that is much more efficient than conventional spark ignition. Under some conditions, it can reduce fuel consumption by 25 percent, says William Green, a professor of chemical engineering at MIT who was coauthor of the new study. That's very similar to the efficiency of a diesel engine, which also achieves combustion by compression rather than a spark. But unlike diesel engines, HCCI results in a more uniform combustion and is thus much cleaner.

Source:
MIT Technology Review, Friday, August 03, 2007, A More Efficient Engine, A new type of engine could be relatively inexpensive., Kevin Bullis