Walmart* has three goals
Office Depot’s Vision is “To Increasingly
Regulating Lighting Design
Lighting design is regulated in most states by defining the maximum number of watts per square foot. This is called "lighting power density" (LPD).
While all states are required to have codes governing LPD many do not police or enforce the limits. The current trend, however is for strict enforcement during planning, inspection and even after the certificate of occupancy is given.
Walmart stores will have skylights used in combination with T8 fluorescent fixtures. The fluorescent fixtures in the skylight area are dimmable so that as the daylight contribution increases the electric light contribution decreases.
Note they have painted the ceiling white, have the fixtures across the aisles and have a polished concrete floor. Each of these factors contributes to the apparent brightness of the space.
If the goal is to be supplied by 100% renewable electricity then the load needs to be reduced.
The sales area loses points in my book because the fluorescent used is the modern-day equivalent of "cool white." Those tubes are known for terrible color rendering and a color temperature of 4100 degrees Kelvin. At night the store takes on a eerie blue glow that is really obnoxious especially with all the POS signage in blue. There is no reason today to use anything less that 80+ CRI.
The message of color rendering and color temperature is not lost on Walmart. In the grocery area ceramic metal halide fixtures are used to make the food appear more appetizing. Meat, bakery, deli and produce respond well to warmer color temperature and better color rendering. Why they used low color rendering is puzzling.
The sign at the entry reads, "This Office Depot location is removing 250,000 pounds of carbon and greenhouse gases from the environment each year through the use of high performance daylighting." High performance daylighting or just "daylighting" means all the light required for the space comes from skylights. Looking closely shows some of the fixtures are off entirely while others are reduced to two tubes.
Skylights for daylighting are a little smarter than a hole in the roof. Some use mirrors to track the sun to get the maximum light into the store while filtering heat. Typically this type of skylight could replace a 1,000 watt metal halide or a fluorescent fixture rated at 800 watts.
Again you see a highly polished, concrete floor and white ceiling. The message about floors and ceilings should be getting clearer. Both features help to brighten the space.
A typical carpet floor would only reflect maybe 10-20% of the light back into the space depending on the color. A black ceiling gives back nothing.
The store pictured is a location in Greensboro, NC. The store in High Point, NC was given a similar treatment during an upfit. Metal halide fixtures were replaced with T5 fluorescent fixtures and the concrete floor polished to a high gloss during the upfit.