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Description
A 1,300-liter-capacity liquid hydrogen (LH2) storage tank has been constructed and tested. The thermal insulation system of the LH2 storage tank is designed to have a boil-off rate (BOR) of 1.5 vol.%/day and a refrigeration system is introduced to achieve zero-boil-off (ZBO) of LH2. A two-stage GM-type pulse tube refrigerator (PT815, Cryomech) is utilized for the refrigeration system. The LH2 storage tank mainly comprises a vacuum chamber, radiation shield, and internal reservoir. The aluminum shield is conductively cooled by the first stage of the cryocooler and it also has a vapor-cooled loop for rapid initial cooling. The stainless-steel reservoir has a fin-array heat exchanger to suppress pressure elevation due to the vaporized hydrogen at its top side. The fin-array is cooled by the second stage of the cryocooler. The annular space between the outer shell and the internal reservoir is evacuated to 10-5 mbar. Although it was originally intended for storing LH2, due to safety regulations, liquid nitrogen (LN2) is utilized to figure out the thermal characteristics of the tank. At the initial process of cooling, LN2 was supplied to the vapor-cooled loop and the internal reservoir, simultaneously. When the internal reservoir was filled approximately 40% with LN2, all the valves were closed with the cryocooler on. The refrigeration system was controlled to maintain an internal pressure of 102 kPa. The experimental results were compared to the simulated results using modified temperature conditions of LN2.
| Submitters Country | Republic of Korea |
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