All right, I'll admit it. The fact that the Netherlands-based revolving-door manufacturer Boon Edam has a model that uses human power to generate electricity is mostly a gimmick. By entering or leaving through the NRG+ Tourniket, a generator built into the revolving door mechanism powers three LED spotlights in the ceiling of the door.
But if it's a gimmick, it's a great one--if it gets more people to use revolving doors instead of standard hinged doors in commercial buildings.
We don't often think about revolving doors, but they can save huge amounts of energy and money in commercial buildings. They save energy because they dramatically reduce the inflow of unconditioned outside air when people enter a building. Just how much energy revolving doors save is a little hard to figure out. There appears to be very little information available on this, and some of the leading energy engineers I contacted about this were not aware of performance data, though they agreed that revolving doors can save a lot of energy. The energy savings will be greatest on tall buildings where the stack effect results in significant negative pressure on the ground floor.
A study at the Massachusetts Institute of Technology (MIT) estimated that in campus building E25 (a seven-story academic building that houses the College of Health Sciences and Technology) the revolving doors allow just one-eighth the air leakage that results from the building's standard hinged doors.
The website of the International Revolving Door Company in Evansville, Indiana, claims that someone entering through a revolving door admits only 26 cubic feet of air, on average, while a swing-door entrance admits an average of 1,800 cubic feet (about 70 times as much). In some cases, the site claims, the ratio is closer to 100:1.
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Look at the latest issue of ASHRAE Fundamentals for more information on revolving doors, the efficiency of which has only recently been officially acknowledged.
In ground floor single-leaf swing doors of a tall building here in Riyadh, I measured an outward air velocity of 2m/s due to building pressurization (to keep hot outside air and dust out), equal to 4 cu m/s of air that had to be made up by cooling that hot (max 40~50°C) outside air down to indoor temperature.
But far worse than that was the air loss through two pairs of sliding doors on a vestibule, because the door controls held both sets open whenever there was more than a little pedestrian traffic through them. This problem is now recognized in the ASHRAE material.
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