Loop Heat Pipes - Their Performance and Potential

Loop Heat Pipes combine the advantages of both heat pipes and Capillary Pumped Loops, while overcoming the limitations of each. Loop Heat Pipes provide very high thermal transport capacities; they can transport heat over long distances, through small cross-sectional tubes and have the capillary pumping capacity to overcome high gravitational heads. Most of these features are available from capillary pumped loops (CPLs), but unlike CPLs, Loop Heat Pipes are inherently self priming and totally passive in operation. This paper describes the operating principles of Loop Heat Pipes, provides performance data from hardware tests, describes some areas of ongoing development, and discusses applications, terrestial as well as space, where Loop Heat Pipes could confer major benefits.