Illuminance degradation of led streetlighting luminaires in a hot environment

Two LED streetlighting luminaires were installed in the city of Al-Ain, United Arab Emirates, one of the hottest regions in the world. The street was closed to traffic and illuminance measurements were taken daily every 10 minutes for 300 days including the summer of 2010. Temperature and relative humidity values were acquired inside the driver compartment of the luminaires and outside of the luminaires. This paper reports the illuminance levels, temperature, and relative humidity data. Illuminance did not change by more than 12 percent throughout the test period. The drop in illuminance was 4.5 percent per 10 degree C for the ambient temperature range of 20-40 degrees C.