Miniature Loop Heat Pipes for Electronic Cooling

Abstract

Thermal management of modern electronics has become a problem of significant interest due to the demand for power and reduction in packaging size. Requirements of next-generation microprocessors in terms of power dissipation and heat flux will certainly outgrow the capability of today’s thermal control technology. LHPs, like conventional heat pipes, are capillary pumped heat transport devices. They contain no mechanical moving part to wear out or require electrical power to operate. But unlike heat pipes, LHPs possess much higher heat transport capabilities enabling them to transport large amounts of heat over long distances in small flexible lines for heat rejection. In fact, a miniature ammonia LHP developed for a NASA space program is capable of transporting 60W over a distance of 1 meter in 1/16”O.D. stainless steel tubing. Therefore, miniature LHPs using water as the working fluid are excellent candidates to replace heat pipes as heat transports in electronic cooling systems. However, a number of operational issues regarding system performance, cost, and integration/packaging must be resolved before water LHPs can become a viable option for commercial electronics.

Parametric analysis of loop heat pipe operation: a literature review

“…Currently, LHP miniaturization is in the forefront of an extensive research and development to provide cooling solutions to the high heat load/heat flux problem of advanced electronic packaging [20][21][22][23][24][25][26][27][28]. The constrained space of such applications requires to design specific LHPs.…”

“…The constrained space of such applications requires to design specific LHPs. Various models have been developed for the LHP characterization [7,23,[29][30][31][32]. The steady state models are useful to size new-designed LHPs and to predict LHP performance for various fixed external conditions.…”

Transient analysis of boiling heat transfer in periodic drying out miniature pools

“…Among the steady-state devices, the most studied are the capillary driven two-phase loops, such as the Capillary Pumped Loop (Platel et al, 1995;Chen and Lin, 2001) and Loop Heat Pipes (Hoang et al, 2003;Riehl and Dutra, 2005;Maydanik, 2005).…”

Experimental tests of a stainless steel loop heat pipe with flat evaporator

“…Many efforts are directed to the improvement of the design of miniature loop heat pipes (mLHPs) being easier fitting them inside very small and compact electronic equipment [4,5]. A great advantage for loop systems with respect to conventional heat pipes, is their wide flexibility in the design of the evaporator and condenser sections.…”