Bringing a little sunshine into our lives

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Cost considerations
The concept for hybrid lighting has been around since the early 1970s, but it has been difficult to make the technology practical.

Japanese researchers previously developed solar collectors with glass optical fibers — which are more heat-resistant, but also more expensive and harder to work with. According to Earl, the glass set-up cost around $40,000 to illuminate 10,000 square feet.

Earl and his collaborators have cut down on costs by using plastic optical fibers — as well as plastic mirrors. They are still in the prototype stage, but they hope to get the price to $3,000 for 10,000 square feet.

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“We are not at that level yet,” Earl admitted.

If they can reach their goal, a building owner in Hawaii could pay for implementing the new technology in 2-3 years, with the savings on electricity bills. In other parts of the country, where sunlight is reduced and utility costs are less, this payback would take longer.

“The cost has to come down for the northern parts of the country,” Earl said.

Side benefits
Oak Ridge National Laboratory has done some field tests with HSL. In one of these tests, the researchers realized that the sunlight coming from the collectors had a noticeable reddish tint during sunrise and sunset.

“We originally thought this might be a problem, but we found that people really liked it,” Earl said. “They would come in maybe a little sleepy, and they appreciated having the softer reddish color. And then in the evening, the red tint would say, ‘Hey it’s time to go home.’”

There have been studies that show that natural light is important for setting our body’s internal rhythms. Some doctors also attribute Seasonal Acquired Depression to a lack of full-spectrum natural light.

But perhaps, most surprising is the fact people buy more in a sunlit store. In 1999, the California Board for Energy Efficiency had a study done on the relationship between retail sales and the presence of skylights. The results showed a 40 percent increase in sales due to natural lighting.

The sales boost may be attributable to a feeling – expressed by some shoppers — that full spectrum light makes the store seem cleaner and more spacious.

Knowing that this 40 percent increase is a strong selling point, Earl and others have created a spin-off company, called Sunlight Direct, which is marketing HSL to retailers. They offer the new technology as an alternative to skylights, which can leak and fluctuate in brightness.

“We’re saying here’s a way to get all the convenience of artificial light, with all the benefits of natural light,” Earl said.

Sunlight Direct plans a project launch in 2007.

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