Life prediction of LED-based recess downlight cooled by synthetic jet

This paper details the adaptation and implementation of a proposed hierarchical model to the reliability assessment of LED-based luminaires. An Edison base ? 6 in., compatible can, downlight ? LED replacement bulb, cooled by active synthetic jets, is used as the test vehicle. Based on the identified degradation mechanisms and the experimentally obtained degradation rate of the cooling device, the reduction in the heat sink enhancement factor, and thus the increase in the LED junction temperature, is determined as a function of time. The degradation mechanisms of the dual-function power electronics – providing constant power to the LEDs and to the drivers of a series of synthetic jets – are also analyzed and serve as the basis for a hybrid model which combines these two effects on the luminaire lifetime. The lifetime of a prototypical luminaire is predicted from LED lifetime data using the degradation analyses of the synthetic jet and power electronics.