Hydrogen Advanced Loop Heat Pipe

Passive cooling transport in the cryogenic temperature regime still remains a challenging task since problems regarding parasitic heat gains from the surrounding have not been resolved satisfactorily. A recently-introduced concept of Advanced Loop Heat Pipe (or ALHP) had demonstrated an ability to manage “excessive” vapor generation in the compensation chamber. Nitrogen and Neon were successfully utilized as the working fluids to provide cryocooling transports in the temperature range of 80-120K and 30-40K, respectively. A Hydrogen ALHP in 2004 became the first capillary-pumped system to operate in the 20-30K range. This paper will present the ALHP technology in general and the detailed description of the research program/test results in particular.