Additive manufacturing of a compact flat-panel cryogenic gas-gap heat switch.

State-of-the-art heat switches are only rarely employed in thermal system architectures, since they are rather bulky and have a limited thermal performance (expressed as the heat transfer ratio between the "On" and "Off" state). Using selective laser melting additive manufacturing technology, also known as 3D printing, we developed a compact flat-panel gas-gap heat switch that offers superior thermal performance, is simpler and more economic to produce and assemble, contains no moving parts, and is more reliable because it lacks welded joints. A prototype measuring 5 x 5 x 1 cm3 outer dimensions is developed with an integrated coolant heat sink to assess the feasibility of the technology. Later a second prototype measuring 3.2 mm thick, 10 cm by 10 cm frontal area panel is developed. An on-off heat conductance ratio of about 45 is measured at 100 K, and the on-conductance is 4.5
W/K. In addition to being compact, this type of heat switch has a large on-conductance compared to other types of cryogenic heat switches. This opens doors to utilize the heat switch for cryogenic temperature control applications.