Review of vapor compression refrigeration in microgravity environments.

• First review of vapor compression refrigeration for space applications. • Summarizing more than 40 years of development. • Covering gas-liquid two-phase flow, thermal gravitational scaling and system design considerations. • Suggesting a general evaluation criterion to select cooling technologies for spacecraft. Using a vapor compression cycle for cooling in microgravity environments was already suggested in the 1970s to leverage the high coefficient of performance. Since then, only a few systems have operated in microgravity with scarce documentation of these flights. The lack of measured data and detailed documentation makes identifying the necessary next steps difficult for researchers entering the field of refrigeration in space. This paper provides a review of available literature for vapor compression systems flown in microgravity by outlining the history of vapor compression devices in space and presenting performance data. Moreover, gaps in the literature are highlighted and open questions are posed based on the reviewed material. Next steps of research are suggested to support and ultimately achieve reliable vapor compression refrigeration in space. Calculating equivalent masses for a fair comparison of different microgravity cooling technologies is proposed by capturing both energy consumption and used volume. [ABSTRACT FROM AUTHOR]