As described by the lab, the Sandia cooler predominantly transfers heat across an air-gap (maintained via self-generated fluid bearing) between the base plate a

As described by the lab, the Sandia cooler predominantly transfers heat across an air-gap (maintained via self-generated fluid bearing) between the base plate and rotating impeller. As described, they claim that if they can maintain the air-gap to 10um, then they get a net win since the specific (per surface area) thermal resistance is sufficiently low (due to only being 10um), and the transfer surface area is comparatively enormous. Nevertheless, the air-gap still forms the dominant component of their overall thermal resistance. Reading through their posted development report [0], it's apparent that they were having trouble hitting that 10um target with their designs. Not exactly a surprise that this is the most difficult part. Not surprising that the "commercialized versions" (see other posts) don't use this mechanism. [0] https://ip.sandia.gov/techpdfs/Development%20of%20Sandia%20Cooler%20SAND2013-10712.pdf https://ip.sandia.gov/techpdfs/Development%20of%20Sandia%20C...