Novel cooling technologies used to improve the power and efficiency of jet engines has been used to reduce the heat transfer rate and the number of chips in an LED bulb. A 1500-lumen LED bulb was successfully demonstrated using the technique, addressing one of the key barriers to more widespread adoption of such bulbs for general lighting. Scientists at GE Global Research, the technology development arm of GE Co., in partnership with GE Lighting and the University of Maryland, demonstrated the bulb as part of a two-year, solid-state lighting program with the Department of Energy (DoE). The LED bulb produced lumens equivalent to a standard 100-W halogen bulb. Mehmet Arik, a mechanical engineer at GE Global Research and principal investigator on the LED project. (Image: Business Wire) “The scientists and technology leaders involved in this collaboration are dissolving some major barriers to the commercialization of general lighting LED bulbs,” said John Strainic, global product general manager for GE Lighting. “We’re taking swings at issues such as higher light output options, thermal management, and bulb size and weight. This kicks open the door to the solid-state age that is upon us.” As part of the DoE project, the research team of professors Bongtae Han and Avram Bar-Cohen at the University of Maryland's A. James Clark School of Engineering have developed and demonstrated novel cooling technologies that effectively manage the heat and promote lower system costs by reducing the number of LED chips required, when compared to conventional cooling technologies. Mehmet Arik, a mechanical engineer at GE Global Research and principal investigator on the LED project, said, “This is a revolutionary cooling technology with great promise. It has the potential to help us take LED lighting performance and efficiency to new heights. Through further research and improvements, we may be able to increase performance without compromising the efficiency or lifetime of an LED bulb.” Aviation and Energy roots GE’s cooling solution is based on technology the company now uses in its aviation and energy businesses. The company has a team of fluidics experts who specialize in technologies that manage flow. They are developing innovative ways to control airflow and combustion to dramatically reduce the amount of pressure losses and loading characteristics in aircraft engines and power generation in gas and wind turbines. “Just one floor down in the same research building, I have colleagues using our dual cool jets technology to improve both the power and efficiency of the jet engines and power generation turbines,” Arik said. “With wind turbines, for example, we’re manipulating airflow to increase wind energy production. With LEDs, we’re using dual cool jets to improve the heat transfer rate and reduce the number of chips in the lamp.” How the dual cool jets technology works The dual cool jets are very small microfluidic bellows type devices that provide high-velocity jets of air, which impinge on the LED heat sink. These jets of air increase the heat transfer rate to more than ten times that of natural convection. The improved cooling enables LED operation at high drive currents without losses in efficiency or lifetime. For a given lumen output, the dual cool jets’ improved thermal management reduces the necessary LED chip count. This, in turn, can dramatically lower the cost of the lamp. In addition to performance and cost advantages, this cooling technology enables reductions in LED lamp size and weight. The project is in its final stages; the organizations are now studying ways to improve the reliability and lifetime of LED lighting systems. For more information, visit: www.ge.com/research