Planar-lighting-enabled parking-area lighting combined with linear surface-mount LED fixtures and traditional LED area lights to deliver an 81% reduction in energy usage for a hospital parking lot.
Cree has announced a new solid-state lighting (SSL) project at the Reston Hospital Center in Reston, VA. The hospital retrofitted all lighting in its parking garage with three types of Cree luminaires including the LED-edge-lit IG Series luminaire that snared an LEDs Magazine Sapphire Award earlier this year. The use of SSL, along with autonomous control for daylight and occupancy, delivered an 81% reduction in energy usage, equating to just more than $60,000 in annual savings.
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The legacy lighting was problematic both in terms of energy usage and maintenance costs. "Prior to making the switch to Cree’s LED lighting, we were experiencing astronomical electricity bills and excessive maintenance costs from lighting in the hospital’s parking garage," said Chip Cooper, Reston Hospital Center project manager and master electrician. "The material and labor costs of replacing five to 10 globes and 30 or more light bulbs a month were significant, so we were looking for an opportunity to address the issue while enhancing the visibility, safety, and comfort for our patients, visitors, and staff."
While we have often reported on re-lamping cost as a motive for SSL retrofits, the hospital's need to replace fixture globes is a bit unique. Cooper said the prior fleet of 300 175W metal halide (MH) fixtures operated 24 hours a day and generated so much heat that the globes would melt at some point.
The MH fixtures were largely replaced by the IG Series products. Those luminaires utilize the Cree WaveMax technology that was first introduced in April 2015. WaveMax is a planar lighting technology that relies on LED edge lighting. In the case of the IG, four planes form a rectangular fixture that emits inherently diffuse light, and as mentioned won the Sapphire Award in the Outdoor SSL Luminaire Design category.
The SSL project also utilized the LS Series Surface Ambient luminaires in stairwells. Those LED fixtures are part of Cree's TrueWhite brand of products that deliver 90-CRI or better light.
On the roof of the parking deck, the hospital had previously relied on 1000W legacy lights, but Cooper said there were still dark areas and shadows. The Cree OSQ luminaires installed on the roof has now delivered uniform coverage. "Now, it could be two in the morning, and you can see anything in any area up there," said Cooper. "The dissipation of the light is excellent. The color is great. And you can look up towards the light and it’s not going to blind you.”
While the transition to LED-based lighting would deliver baseline energy savings, it's the autonomous control in the hospital project that really amplifies the savings. The IG Series LED fixtures installed throughout the garage parking areas can drop to 10% brightness or even shut off completely in areas where there is sufficient natural light during the day. When motion is detected during the day, the fixtures come to 25% of full output.
At night the fixtures are set to operate at 15% brightness but come up to full output based on motion. And Cooper said hospital security has been pleased with the glare-free design that enables security cameras to capture images accurately. As the nearby photo illustrates, the LED-based garage lighting is extremely uniform yet will not cause drivers or pedestrians discomfort from glare.
