NASA SBIR 2005 Solicitation


SUBTOPIC TITLE:Thermal Control for Instruments
PROPOSAL TITLE:Miniature Loop Heat Pipe with Multiple Evaporators and Multiple Condensers

SMALL BUSINESS CONCERN (Firm Name, Mail Address, City/State/Zip, Phone)
TTH Research, Inc.
14300 Cherry Lane Ct., Suite 215
Laurel, MD 20707-4990
(301) 641-2954

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
Triem   Hoang
14300 Cherry Lane Ct., Suite 215
Laurel, MD  20707-4990
(301) 490-1800

TECHNICAL ABSTRACT (Limit 2000 characters, approximately 200 words)
Loop Heat Pipe (LHP) is a high performance heat transport device using capillary forces to circulate the working fluid in a closed loop. Conventional LHPs usually have one capillary pump (evaporator) to acquire waste heat from a heat source. Recent efforts have focused the development of LHPs that contain two or more evaporators. Even though two-evaporator LHPs performed very well, the volume of each compensation chamber (CC) became much larger than that of the single-evaporator counterpart. The reason was that all but one CC would be liquid-filled during normal operation. The one that was not liquid-filled had to be large enough to accommodate the system liquid expansion at maximum temperature. As a result, LHPs with more than 3 evaporators were not feasible for practical applications simply because the CCs became prohibitively large. In the current research, the CCs of a multiple-evaporator LHP were capillarily-linked. In other words, the CCs always contained a mixture of liquid and vapor (two-phase), allowing the loop to operate with a much smaller fluid charge. Consequently the required CC volume was also reduced.

POTENTIAL NASA COMMERCIAL APPLICATIONS (Limit 1500 characters, approximately 150 words)
As electronic devices place ever-increasing demands not only on power requirements but also on packaging technology to reduce size and weight. As a consequence, high performance thermal management technologies, especially high heat flux cooling, have to keep up with the heat dissipation needs. High power electronics are employed in applications ranging from all electric vehicles to radars (both space-based and terrestrial). Examples of high power electronics are power converters, switches, motor drives. In addition, recent advances in laser technology impose a tremendous increase in heat flux requirements of laser diodes. Unless a high heat flux cooling technology such as the proposed cooling concept becomes available soon, recent advances in power electronics cannot be realized.

POTENTIAL NON-NASA COMMERCIAL APPLICATIONS (Limit 1500 characters, approximately 150 words)
The cooling technolgy is also applicable to provide thermal management of the avionics and electronics in military vehicles. LHPs are needed mainly due to high acceleration conditions, transport length and small diameter requirements for the transport lines.

NASA's technology taxonomy has been developed by the SBIR-STTR program to disseminate awareness of proposed and awarded R/R&D in the agency. It is a listing of over 100 technologies, sorted into broad categories, of interest to NASA.

Energy Storage
Thermodynamic Conversion
Ultra-High Density/Low Power

Form Printed on 07-25-06 17:04