Evaporative Spray Cooling for High Power Solid State Lasers
Summary:
Rini Technologies, Inc. (RTI; Orlando, FL), developed and patented a unique way of spray cooling solid-state laser components at less weight, with less bulk, than current water-based laser cooling systems. The RTI method combines spray cooling and refrigeration in a unique nozzle array design that reduces coolant flow rate to the laser by a factor of ten compared to water-based techniques. Company engineers estimate that using the spray cooling method reduces the overall size and weight of a total cooling system by a factor of three or more compared to current state-of-the-art cooling equipment.
Technology Description:
The spray nozzle array pattern and overall package configuration is volume efficient. A spray nozzle impinges liquid droplets onto the heated surfaces of laser components and removes heat as the liquid vaporizes. By taking advantage of the phase change of the liquid coolant, a tenfold reduction in coolant flow rate (over that of single phase convective techniques) is possible. The action of the spray cooling enhances standard pool boiling. Once coolant has vaporized and cooled a laser component, the exhaust flows back to an integrated refrigeration cycle to be condensed. The heat acquired from the laser is rejected to the ambient environment.
The way the nozzles are designed makes them orientation independent. RTI's technology has demonstrated heat removal rates as high as 700 W/cm2 at 15ºC using ammonia as coolant. The company's unique vapor-atomizer nozzle design uses compressed ammonia vapor to atomize the liquid supplied to the nozzle array. RTI's spray cooling loop combines their vapor-atomizer with an integral vapor-compression refrigeration cycle into one closed-loop spray cooling system.
MDA Origins:
The agency awarded RTI a Phase I SBIR contract in 2000 and followed up with a Phase II SBIR contract in 2001. Until now, high-powered lasers in the 100-kilowatt range have all been chemical lasers. The ability to cost-effectively cool 100-kilowatt next-generation solid-state lasers under the harsh environmental conditions encountered in a tactical mobile platform, while meeting the strict size and weight specifications associated with these platforms, is an important technology area for the military.
Spinoff Applications:
This spray cooling technology has potential commercial applications for high-power industrial lasers used for metal cutting, drilling and welding, as well as the next generation of high-power medical, telecommunications and microwave devices.
Commercialization:
RTI invites inquiries from interested parties who may need a compact and lightweight laser cooling solution. The company is seeking to secure ongoing development contracts to further develop this spray cooling technology to withstand the rigors of real-world conditions. RTI is currently applying for patent protection on several unique aspects of their spray cooling technology.
Company Profile:
RTI began doing business in June 2000 and currently has 12 full-time employees. It occupies a 5,000 sq. ft. facility in Orlando, FL. In 2003, the company had revenues of approximately $1 million, and is on track for $2 million in 2004. Currently, most of its revenue is derived from government-funded contracts.
Contact Information:
Daniel P. Rini, Ph.D.
Rini Technologies, Inc.
3267 Progress Drive
Orlando, FL 32826
Tel: (407) 737-7840
Fax: (407) 384-2123
email: info@rinitech.com
web: www.rinitech.com
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