(Author: Judy Lin, Chief Editor, LEDinside)

Miniaturization and rising efficiency in LED chip designs has initiated redesigns in heat sinks, which are becoming more compact and turning to new designs to achieve faster thermal dissipation, said MechaTronix General Manager Koen Vangorp during an interview with LEDinside at Taiwan International Lighting Show 2016 (TILS) that took place recently in Nangang Exhibition Hall, Taipei.

“Three years ago, people were less aware of the importance of cooling in LED lighting,” said Vangorp.

This is changing, though, due to rise of high power compact Chip on Board (CoB) and Driver on Board (DoB) designs that are requiring luminaire vendors to invest in more effective cooling solutions for LED luminaires.

In the past, aluminum heat sinks were sufficient for 50W to 70W LED luminaire applications, but tremendous shift in mid-power LED chip efficiency from 100 lm/W to 200 lm/W has demanded for more efficient and rapid thermal dissipation designs on the market, said Vangorp.

To meet thermal dissipation demands, MechaTronix introduced their patented CoolTube® into its high-power heat sink designs. The copper coated tube structures contain four 1.7mm-sized closed-loop heat pipes, each tube is filled with liquid that can rapidly transform into heat under low temperature difference, and quickly dissipate thermal energy from the heat sink device, explained Vangorp. By placing the CoolTube® in the center of the heat sink, a 20 cm diameter heat sinks can rapidly cool down 550W high bay light by passive cooling. No additional fan structures are needed with this design.

The emergence of DoB technology also has a small impact on LED thermal dissipation design. LEDs were normally driven by a constant current driver outside of the design. With the AC to DC Driver-On-Board design now integrated on the LED engine, extra power loss from the power conversion has to be cooled down In general, DoB designs have more than four to five LEDs soldered onto the board, and every LED has to be cooled to the same temperature simultaneously to prevent color shift, explained Vangorp. However, in DoB designs the LEDs located closer to the driver will be heated to a slightly higher temperature than rest of the LEDs, hence the driver has a small effect on cooling.

To illustrate the advancements in LED efficiency and brightness designs, Vangorp pointed it would take only six to eight 65,000 lumens LED luminaires to light up the 300 meter tall 85 Sky Tower in Taiwan’s southern capital Kaohsiung. Mechatronix collaborated with Khatod, Almeco, and Citizen using the Japanese chip manufacturers LED engine CLU550, nicknamed the “Monster”, and the luminaire attracted a lot of interest from LED luminaire manufacturers at the show. The heat sink manufacturer specializes in high power LED luminaire application has collaborated with many leading LED chip manufacturers in the industry, such as Lumileds, Citizen, and Osram.

Zhaga to launch Book 15 in 2016

As a Zhaga member, the company has been designing heat sinks that can fit all lighting components and drivers, such as those designed by Meanwell. The driver manufacturer’s round design has impacted MechaTronix CoolBay® high bay LED cooler designs, which is made especially to fit with the HBG LED drivers. Emergence of CoB designs on the market also urged Zhaga to create new standards.

Asked if Zhaga had any plans of releasing new standards this year, Vangorp noted the emphasis was on industrial lighting light engines this year. In the past, most of the standards were mostly related to commercial lighting applications, but Book 15 “rectangular LED modules for use with lens array” is specifically aimed at outdoor lighting applications. Book 15 which is still being drafted by the consortium will support 2x2, 6x2, and 8x2 arrays for outdoor lighting applications, said Vangorp.

For the LED heat sink manufacturer that specializes in high power LED luminaire sector, the outlook remains bright. Vangorp was especially optimistic that the global horticultural lighting market, which is valued at US $3 billion would offer plenty of opportunities as applications widened from LED grow lights to sorting foods, egg fertilization, and other new applications. These applications also present new opportunities for heat sink makers, since most of these applications require temperatures to be kept at low temperatures to prevent livestock or plants from being affected by heat emitted from lights.

Trends in LED chip design, such as emergence of CoB and DoB in high power LED luminaire designs are also driving heat sink designs, where new materials and design concepts such as heat tubes are used. Emerging new high power LEDs is also driving Zhaga standards to shift from commercial lighting to outdoor industrial lighting sector. Moreover, as new applications emerge in the temperature sensitive horticultural lighting segment, the industry is expected to introduce new opportunities for LED lighting and heat sink market.