In August 2007, Cree’s management made a bold decision to replace the existing fluorescent lighting technology at its Durham, NC facility with new energy-saving, environmentally friendly LED lighting technology. The group started with the company’s headquarters building, but eventually plans to replace more than 7,000 existing fluorescent light fixtures covering more than 800,000 square feet campus-wide. Phase one replaced 200 existing fixtures in 7,000 square feet of space in the visitor lobby, waiting areas and conference rooms. All the exterior parking lot lighting was also converted from high-pressure sodium to LED lighting. Both parts of phase one had to be completed by early November 2007, just 3 months later.
To make phase one a reality, the facilities team needed vendors that had the capability to use emerging LED technology; to produce commercially available LED lighting fixtures fast; and to incorporate Cree lighting products — specifically XLamp lighting products — into the fixture design. This was challenging since many LED lighting vendors had not focused on LED lighting retrofit solutions to replace existing commercial grade 2×4 T8 fluorescent troffers, concentrating instead on LED lighting for under-counter applications, residential cans, and architectural decorative lighting. Cree needed to find vendors that could make commercial-quality LED 2×4 T8 troffer fixtures.
After networking with the sales and marketing teams and doing extensive research and phone interviews, the facilities engineering team identified five vendors out of an initial pool of 30 companies with the technical expertise to provide commercial-quality LED lighting that could complete phase one within the limited time frame. These five vendors were asked for product samples for testing to determine if they were the high-quality, application-appropriate LED lighting solutions with the “form, fit and feel” needed to assure the installation would be successful. This selection effort also involved a visit to each of the vendors’ manufacturing locations to conduct source inspections, quality control checks, and answer LED light fixture designers’ questions. This process was completed over a six-week period.
Designing LEDs into any illumination product requires a decision between designing a complete luminaire based on LEDs, or an LED-based lamp meant to install in an existing fixture. Generally, a complete luminaire or fixture design will have better optical, thermal, and electrical performance than the retrofit lamp, since the existing fixture does not constrain the design. In the end it is up to the fixture designer to decide whether the total system performance of a new luminaire or the convenience of a retrofit lamp is more important. If the target application or the customer’s need is better served by creating a new LED fixture, then designing the light output to match or exceed an existing fixture has several advantages. First, an existing design is already optimized to target a known application and can, therefore, provide guidance for setting the design goals around light output, cost, and operating environment. Second, an existing design is already in an accepted form factor. Switching to LED technology is easier for the end user or customer if the form factors are the same.