NREL Building Uses 'Light Louvers' to Reduce Need for Electric Lighting

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nrel windowA new research facility at the National Renewable Energy Lab near Golden, Colo., uses innovative design elements such as "light louvers" to reduce the need for conventional lighting.

The curve of the light louvers, which are suspended within the window, catches the light and bounces it deep into the building - about 10 feet deeper than it would naturally, according to a press release.

"The windows are literally the balance point in how the building manages energy," said Philip Macey, project manager for Haselden Construction, which is building the structure. "Get the windows too big and you'll get too much heat gain and heat loss. Too small and you won't get enough daylight to light the interior of the building to the middle of the floor plan."

The 222,000 square-foot research facility, when it opens this summer, will house more than 800 staff and an energy efficient information technology data center.

Considering that 19 percent of the U.S. energy portfolio goes toward commercial buildings, the department is building the facility as a showcase for energy efficiency that can replicated by the building industry.

As another method of reducing energy use, once the building is active employees will be notified when to open windows to let cool air in or shut them to keep warm air out, as predicated by the needs of the building.

The building also will be testing two new kinds of windows.

Electrothermic windows, which can be tinted with a small electrical charge, will keep out heat and reduce load on the HVAC system.

Thermochromatic windows have glass that reacts to temperature changes, helping reduce heat transfer.

"You don't get the fine control of the electrochromic windows but, the thermochromic windows are cheaper and it's a killer technology," said NREL Research Scientist Dane Gillaspie.

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