High Lift Heat Pump

NASA has identified a need for higher heat rejection temperatures due to an equatorial lunar mission profile, where surface temperatures reach 400 K. To meet this need for space exploration vehicles to reject waste heat to high temperature heat sinks, Mainstream proposes adapting our oil-less vapor-compression (V-C) refrigeration compressor technology for operation at high temperature and high lift. Vapor-compression systems use two-phase heat transfer which reduces component size and mass over single-phase heat pumping cycles such as reverse-Brayton or Stirling. Mainstream?s current oil-less V-C compressor technology is gravity-insensitive, has a long operating life, can be scaled to match various heat loads, and has been mission-proven on the international space station (ISS) placing it at a TRL 9. The proposed development effort will extend this compressor technology to operation at high temperatures and high lift, to which it is inherently well-suited. The resulting compressor will be an enabling technology for the needed high temperature heat pumping systems.

The proposed research is targeted at enabling equatorial lunar exploration. NASA has identified a need for improved heat rejection systems in this environment, where surface temperatures can reach 400 K. The required heat rejection temperature exceeds the maximum heat rejection temperature of commercially available compressors. Our technology will enable space-based heat pumping systems at these temperatures. Mainstream expects that this will result in other NASA applications, such as non-lunar exploration vehicles with very high heat rejection loads.

In addition to NASA?s lunar exploration mission profile, Mainstream?s compressor technology has potential to benefit any space-based system that must reject large amounts of heat through radiation. In these cooling systems, radiators are almost always the largest contributor to size and weight. By increasing the rejection temperature through a lifting cycle, such as the V-C refrigeration cycle, radiator size and weight can be significantly reduced. It can be assumed that any satellite or exploration vehicle that has high electric power consumption (1000s of watts or greater) is going to have large heat rejection requirements, due to the inherent inefficiencies of any real system. These high power satellites could potentially benefit from a lifting cycle.

This is early/mid-stage (TRL 4) — the most realistic path in is NASA SBIR/STTR, which funds small businesses and research institutions to develop technology aligned with NASA's needs (equity-free, phased funding). Check whether a current SBIR/STTR solicitation topic overlaps with this project's technology area, or contact the project directly (above) to ask.

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