NASA SBIR 00-1 SOLICITATION

FORM 9B - PROJECT SUMMARY

PROPOSAL NUMBER 00-1 20.01-9569 (Chron: 000432 )
PROJECT TITLE
High Heat Flux Electronics Cooling Cycle

TECHNICAL ABSTRACT (LIMIT 200 WORDS)
The area/volume power densities of packaged electronics will continue to increase until the method of heat rejection is the sole performance limiter. Perhaps the most reliable long-life cooling systems finding applications in space are passive; namely, heat pipes. Unfortunately, the balance between capillary pressure and viscous resistance limits the performance of these devices. Overall fluxes of 100W/cm^2 may be achievable with such systems, but local fluxes will never exceed pool boiling critical heat flux values that peak at approximately 100W/cm^2, but are normally much less. The novel thermal cycle proposed here circumvents this limitation. The cycle is passive yet generates pressure gradients substantially larger (up to 100-fold) than capillary systems. Such pressure differentials may be exploited to achieve very high forced-convection phase-change cooling rates (i.e. flow boiling/spray cooling) in coupled evaporators by direct contact with MCMs, or by more traditional flow-through designs. Heat fluxes obtained in this manner exceed those of capillary systems and are ~O(500W/cm^2). In Phase I we will demonstrate the high heat flux capability of the cycle exceeding 100W/cm^2 from simulated 2-D surfaces or 3-D MCM stacks. In Phase II we will produce an optimized design for high flux space electronics (i.e. satellite) heat rejection.

POTENTIAL COMMERCIAL APPLICATIONS
NASA can benefit greatly from a thermal system whose performance is similar to a mechanically pumped loop, but does not require a pump. If the cycle proposed is successfully demonstrated it could prove valuable to NASA as a passive, versatile, low-mass, high-performance cooling cycle for high-density electronics cooling, power conditioning, or even at the large scale in power cycles and thermal radiators. However, the business that has the greatest near-term commercial potential is the use of high heat flux loops for high-performance electronics cooling in terrestrial applications. High-end computing/electronics requires heat removal from high-density sources. Thus heat fluxes are large and only enhanced convective heat transfer techniques can transfer such heat rates the required distance between heat source and heat sink. The proposed inexpensive, robust cycle can transfer heat loads comparable to mechanically pumped loops, it is silent, and it can provide uniform temperature cooling at the heat source without drawing additional power. These cycle characteristics are attractive, as current commercial solutions become incapable of the increasingly demanding heat load requirements of microprocessors and power electronics.

NAME AND ADDRESS OF PRINCIPAL INVESTIGATOR (Name, Organization Name, Mail Address, City/State/Zip)
Dr. Mark M. Weislogel
TDA Research, Inc.
12345 W. 52nd Ave.
Wheat Ridge , CO 80033 - 1917

NAME AND ADDRESS OF OFFEROR (Firm Name, Mail Address, City/State/Zip)
TDA Research, Inc.
12345 W. 52nd Ave.
Wheat Ridge , CO 80033 - 1917