I want to
make a LED Light to replace a standard halogen down lighter. For this I will be
using 16W Led bulb. Can some one suggest me the heatsink design for this so
that it can fit into compact area?
In order to be able to help you, I would need some info about the device you are using (RThj-c, Tmax, physical dimensions) as well as about the enclosure of the lighter (volume available, shape, type - hermetically sealed or open-air). You may also need to add some kind of thermal protection / current limiting circuitry depending on the power source you are using (constant current controlled would be desirable). BTW, do you have a datasheet for the 16W LED bulb?
If I understand correctly, you already have the power conversion stage from 220V AC to a 300 ... 350mA constant current source (are you using a serial configuration for the LEDs?). Assuming an85% conversion efficiency, you may need to dissipate around 18W. Since the LEDs are already mounted on individual heatsinks, you just need to screw down the LEDs on an aluminum plate that will have the opposite side cooled by natural convection (some 20mm space between the heatsink and ceiling would help significantly). A 300mm x 100mm, 2mm thick aluminum plate should be enough for a room that doesn't heat up more than 30C degrees. Since I was not able to find a maximum operating temperature and thermal resistance data for the device in the datasheet, I searched for the OVSP_4CR44 spec and I found that the same company offers 20 LEDs on a single heatsink, already mounted in strings of 5 series/ 4 parallel (may be helpful also). Bottom line: since no Rth and Tjmax are given, the nature of the problem is more experimental. You can start from whatever heatsink fits into your available space and if mass production requires more cost efficient design, you just operate the system in a worst-case condition and measure the temperature at heatsink level to check if you can shrink it down safely. Assuming uniform heat distribution for Pd = 18W, a 125C Tjmax and an average aggregate Rth of 2.5C/W, we get a heatsink maximum temperature of 80C (Tjmax - T_heatsink = Rth Pd). Since we can only guess the Rth at this moment, this calculation is just an example. Real numbers must be found by contacting the manufacturer for a reliable design. If data not available, the experimenal way is the only one.
Catalin, I whole heartedly thank you for your precious time you have given to help me find the solution. It is very valuable to me.
I also have received message from Robin Elkins of Elkindustries that it will be impossible to make a Hermetically sealed design in this case. So, I am now planning to make an open one.
You are welcome. Since you have to design it as an open system, you may try to use holes on both top and bottom of the enclosure (or lateral if bottom has to be a single-piece transparent glass). The natural air convection will improve the thermal profile. You can drill holes in the mid-points between the LEDs so the warm air will flow upwards naturally. Good luck!
I'm having a similar issue and any help would be appreciated.
I'm working on a project where in the 18 nos. of 1W HB LEDs are soldered on an individual MCPCB and further these 18 MCPCB (with LED attached) needs to be mounted on an aluminum heat sink using a thermal adhesive or similar.
My questions is - what is the best approch to determine the right heat sink in terms of dimensions, number of fins, fins size etc.
I have already calculated the thermal resistance values of the heat sink - ambient using the thermal modelling.
RUGGED, ROBUST, OEM/LABORATORY DIODE LASER MODULE "BREAKS RECORD" FOR POWER @ WAVELENGTH IN THE DEEP VIOLET
DATELINE: MELBOURNE, FLORIDA (USA), NOVEMBER 11, 2011 -FOR IMMEDIATE RELEASE-
ELK INDUSTRIES, LLC has achieved a "Breakthrough" in Output Radiant Flux for a CW Diode LASER Module at 398 - 401 nm. In the R&D Laboratories of ELK Industries, this milestone advance allows New and useful advances in the arts and sciences. A rugged and robust, variable power OEM/Laboratory LASER Operating at 401 nm with Output Power of 400 - 500 milliwatts (High Power) was Demonstrated for the first time in North America. It's Power Input is only 2 Watts at 100 - 240 VAC, 50 - 60 Hz, and LASER Diode Input of 393 milliamps at 5 volts, D.C., for full Output Power. The Highly collimated Output appears as TEMoo with a Focal Point of (only) 500 microns, or less. Additional collimation allows for Transmission for distances of over 1 kilometer. This advance "Opens Up Doors" into Research not possible, or practical, in the past. Especially due to the High Power and High Quality Beam Characteristics, this LASER can enable (New) Research in Fluorescence Lifetime Studies, Materials Research, Direct - Diode LASER Pumping of Dye Liquid LASERS, LASER Ablation Spectroscopy, LASER Marking & Engraving, Micromachining - especially of Organic Materials, Forensic Studies, Near UV LASER Illumination, LASER Light Shows, LASER Projection systems and Displays, Counterfeit Detection, and a host of other unique applications. The (overall) size of the LASER Module is (only) ~ 4" x 6" x 5". The LASER Diode, itself, is made in a Standard TO-18, 5.6 mm Can. The LASER Diodes are also available from ELK Industries, as a "Stock Item". This Product set is called the "DEEP VIOLET LASER". At ELK Industries, extreme utility of this LASER is key to the Development of Tunable, Direct - Diode LASER (CW) pumped Dye Liquid LASERS operating in the Blue or Blue-Green Wavelengths, as well as the 550 - 620 nm wavelength region. Researcher, and CEO of ELK Industries, Mr. Robin Elkins, has already achieved High Power CW Direct Diode LASER pumping of Rhodamine 590 Chloride with the "BLUE MAXTM OEM/Laboratory LASER", which Produces a diode LASER Output of 1 Watt at 440 nm (Maximum). Other, proprietary applications are being investigated for potential Industrial Uses on a Large Scale. These OEM, 398 - 401 High Power Diode LASER Modules are planned for immediate release, as the Diode LASER Lifetime, and "other" Key Diode LASER Characteristics have been well established, earlier this Year. These OEM/Lab LASER Modules are manufactured in the USA.
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