Light Emitting Diodes (LEDs)
A limitation of current LED lamps is heat transfer; high temperatures over time degrade performance. Most lamp manufacturers have adopted a large aluminum heat sink to address this issue. The heat sink and the upstream manufacturing of the aluminum have been identified as the primary environmental concern for the lamps. This presents a unique opportunity for research that will improve the thermal performance of the LEDs, reduce the size of the heat sinks, demonstrate cutting edge modeling techniques, and educate the lighting industry about thermal design. Undergraduate students are currently leading the experimental testing of existing LED products and thermal calculations.
The team of research students constructed a thermal testing environment designed to provide a "worst case" thermal environment for lighting products. The test chamber was designed to be thermally equivalent to a residential ceiling with a recessed can fixture. The thermal chamber includes instrumentation to allow temperature measurements at 1 second intervals over time in multiple locations on the lighting product and the environment.
Using the thermal testing chamber the research team is testing the performance of a variety of LED products to characterize the performance of the heat exchangers. The thermal evaluation will be compared to the more common CFL and incandescent products.
The team is also working on end of life and sustainable features in LED lighting. An updated life cycle assessment is underway with collaborators at UC Berkeley.
Prior Work
At the Pacific Northwest National Laboratory I led a team of researchers to develop a comprehensive assessment of LED lighting when compared to traditional CFL and incandescent options. Our study confirmed that over the life of most lighting products the use phase is the dominant factor for energy and environmental impacts. For this reason, LEDs are a significantly better choice since they operate at lower wattage than incandescent and CFL products.
We also found that the only area where the CFL was a bit better than LEDs is in the category of landfill waste. This category is driven primarily by the relatively large amount of aluminum in the LED heat sink. In the short term this issue can be resolved with recycling, but in the longer term it makes sense to work on improving heat transfer in LEDs. This research provided the motivation for the current research at the University of Portland on thermal performance of lighting products.
