Water Cooling of High Power Light Emitting Diode

The development in light technologies for entertainment is moving towards LED based solutions. This progress is not without problems, when more than a single LED is used. The amount of generated heat is often in the same order as in a conventional discharge lamp, but the allowable operating temperature is much lower. In order to handle the higher specific power (W/m(3)) inside the LED based lamps cold plates were designed and manufactured. 6 different designs were analyzed through laboratory experiments and their performances were compared. 5 designs cover; traditional straight mini channel, S-shaped mini channel, straight mini channel with swirl, threaded mini channel with swirl and 2 parallel mini channels with swirl. In the 6th design traditional mini channels were used. Based on the experimentally obtained heat transfer inside the cold plates, it was concluded that the mini channels utilizing swirling flow were much more efficient than channels with traditional flow without swirl. Similar conclusion was made for the design utilizing mini channels. Considering the pressure difference across the cold plate in addition to heat transfer properties, it turned out that two solutions were preferable; axial flow through mini channels or a s-channel. Experiments showed that the channel design utilizing swirling flows had up to 4 times the pressure loss as the mini channells-channel.