As it has been released, Cree has realized a new retrofit project at the Bowling Green State University (BGSU) near Toledo. Initially the university considered replacing the previously installed metal halid lamps (MHLs) with fluorescent tubes, but finally decided to retrofit the MHLs with LED high bay lamps due to their superior energy saving potential. The retrofit project was applied in an indoor area.
   
The previously used MHLs didn’t match the expectation of the university’s facility management any more. Particularly the MHLs high energy consumption, poor light quality and insufficient brightness levels had been in the center of criticism. The university had long time considered a change to old MHLs, the only reason of hesitation had been the high cost of buying new LEDs. However, with its new high bay lamp-series, Cree was able to offer a high bay lamp at a competitive price level.
MHLs of 400 Watt were replaced with LED lamps of 230 Watt with an efficacy of 100lm/W. Cree offered a 10-years warranty and therefore the university expects to have little to no issues with maintenance costs in future. Whilst the MHLs had caused extraordinarily strong light spots next to shadowy areas, the LED-lamps light distribution is now much more even resulting in an overall improved feeling of quality of light.
Another big advantage of the LEDs are their instant turn/off which allows the university to switch off the lamps, when light is no efficiently used. The old MHL-fixtures had frequently not been turned off in order to avoid problems the lamps’ long warm-up times which caused additional energy consumption.sm.