An Instructive Breeze from Ceiling Fans

Most ceiling fans are paragons of inefficiency and poor design. Their motors are among the least efficient possible. Manufacturers get away with low efficiency because the fan itself cools the motor and carries away the waste heat. The fan blades are the most primitive, least aerodynamic shapes that one can imagine. Most are crude paddles. Designers of airplane propellers (who also needed to move air) abandoned paddles almost a century ago, but ceiling fan technology somehow never escaped the 1800s. Finally, the controls barely control, leading the fan to operate when it isn't needed, to spin the wrong way, or just to spin faster than is needed.

This is why news of a new, high-efficiency ceiling fan is important (see "Cutting Edge Blades Slash Fan Energy Use," pg 7). The product is not yet on the market, but the concept demonstrates that huge--up to 50%--end-use energy savings are still possible. It also demonstrates how an integrated approach is likely to save more energy than attacking just one fan component.

The researchers at Florida Solar Energy Center (FSEC) addressed four aspects of fan energy use when investigating ways to save energy. First, they improved the aerodynamic qualities of the fan blades, making them move more air with less input energy. Second, they used the smallest possible fan motor that would provide the optimum air flow, which resulted in less energy use and waste heat. (FSEC would have preferred a more efficient motor as well, but they could not convince the manufacturer to use it.) Third, they developed smarter controls to ensure that the fan operates only when the occupants really want it.

And fourth, the savings do not stop with the fans. People often overlook the fact that ceiling fans are closely linked to lighting options (the fan must be above any overhead lights; thus lighting is usually part of the fan package). Fans with fixtures designed for efficient lights, as FSEC's new fan is, save even more energy.

Some potential improvements, like more efficient motors, may take a while longer to appear in the market. And the higher-end fans that feature more energy-saving measures may not sell as readily as cheaper models, because first cost is still the consumer's highest priority. Still, we can expect to see some market penetration. Manufacturers may promote other aspects of fan performance, such as quiet operation or pleasant lighting, ahead of the invisible energy savings. Still, projects like this one show how far energy efficiency can go.

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