Cooling High Power UV LEDs for Curing Applications

In conventional lighting, visible LEDs (Light Emitting Diodes) are seeing explosive growth in a variety of applications driven by low power consumption, long life and environmentally friendly materials used in their construction. According to the US Department of Energy from 2010-2030 the cumulative energy savings are estimated to total approximately 1,488 terawatt-hours, representing $120 billion at today’s energy prices, and would reduce greenhouse gas emissions by 246 million metric tons of carbon.

UV-LEDs are also seeing ever increasing adoption in curing applications for many of the same reasons – high efficiency, greater than 10,000 hours lifetime, green technology with no mercury disposal issues, no ozone production and no volatile solvents. Additionally, with optimized formulations of inks and adhesives, cure quality and durability have been found to be superior. Early adopters of UV LEDs have shown a long-term commitment to environmental and energy concerns.

Although UV-LEDs are efficient, their high power can lead to high temperatures which can dramatically reduce their lifetime and performance. Large stand-alone chillers are typically chosen to cool the UV diodes on ink curing systems. The chillers are often larger than the UV systems themselves and take up precious space on the processing floor where these units are utilized. The requirements include tight temperature control to a level slightly above ambient and control communication to the UV unit to assure the cooling system is functioning while the UV heat is operational. Our customer was seeking a replacement to their large chiller system to cut down shipping cost, save on floor space, save weight, and lower power consumption so they could provide a better value proposition for their customers. A small chiller to meet their cooling load of 400-900 watts was required.

When approached with this challenge, Aspen Engineers developed a 2RU high chiller system (3.5” tall) with the ability to be mounted in a 19-inch-rack or placed on a workbench.

This new unit leverages the variable speed capability of the Aspen compressor to meet stringent temperature control requirements.  In addition a variable speed coolant pump that is adjustable to provide from 1-4 Liters per Minute flow and up to 60PSI makes the new chiller suitable for a wide range of applications.  The RMC-800 and RMC 1100 units will meet a wide range of cooling requirements in UV LED, Laser, and medical applications.   As a complete system, all that is needed for the user is to add coolant and connect the system to the device to be cooled.  This system is well positioned to replace both larger vapor compression chiller units, and thermoelectric driven chiller systems.  It will draw less than one quarter (1/4) the power of a typical thermoelectric chiller.

According to Deivis Parejo – Business Development Manager at Honle UV America, Inc. “The Aspen RMC-800 is ideal for use with our LED Powerline series.  The chiller is less than one quarter the size and less than one eighth the weight of more conventional chillers”.

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