Feb 19 2008 10:48PM | Permalink | Email this | Comments (0) |
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The first time I walked through, I though the new Wal-Mart in Highland Village, TX was haunted. Like most Wal-Marts, this monster store never closes, and I take advantage of all-the-time access to complete my shopping very late at night when the store is almost totally devoid of other customers to slow me down.

I was wondering down the deserted frozen food aisle when something unexpected occurred. As I walked past the frozen waffles, the cooler case spontaneously changed from a darkened state:

to a lighted state

At first I thought a playful poltergeist (or a bored store clerk) was tricking me because a moment later, the lights in the case shut off again. Just then, I noticed the motion sensor above the case.

A few experiments proved I had not encountered a lingering spirit. Instead, Wal-Mart had installed controls on their refrigerated spaces to assure the lights only turn on when a consumer is peering into the case.

Lighting in refrigerated cases is particularly problematic for energy conservation. Supermarkets know that well-illuminated products outsell poorly lit products. Unfortunately, cold cases naturally reflect outside light, making the food inside appear dark and unappealing. Thus, fluorescent bulbs are placed inside refrigerated spaces to provide proper product lighting. However, these bulbs are usually always on, and the energy they dissipate as heat must be lifted out of the refrigerated space.

Hence, these cases normally present a double energy penalty. First, extra lighting must be used to showcase the enclosed product. Plus, extra energy must be expended to remove heat generated by that light source out of the cold space.

Keeping the lights in refrigerated cases off until a customer is in close enough proximity to see the products inside is a simple, elegant, and clever adaptation of lighting controls to mitigate unnecessary energy guzzling.

Clearly, Wal-Mart understands energy efficiency.

I, of course, spent the next 30 minutes running up and down the refrigerated food aisles, creating a “wave” of light akin to a baseball game. The motion sensors turned the lights in those colds cases on and off as I whizzed past with my shopping cart.

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