raw · papers · ingested 2026-07-19
Passive sub-ambient cooling: radiative cooling versus evaporative cooling
Source: https://arxiv.org/pdf/2107.04151
Authors: Ablimit Aili, Xiaobo Yin, Ronggui Yang. arXiv:2107.04151 [physics.app-ph], submitted July 9, 2021 (v3 revised December 11, 2021).
Key findings
Direct experimental comparison of a radiative cooler and an evaporative cooler under real clear-night-sky exposure:
- At low humidity (13% RH, 26.0°C ambient): evaporative cooling beat radiative (−15.0°C vs. −13.5°C sub-ambient).
- At higher humidity (32% RH, 17.0°C ambient): radiative held up better than evaporative (−11.5°C vs. −10.5°C) — radiative cooling is relatively more resilient as humidity rises, within the tested range.
Important caveat: even the paper’s “humid” test condition (32% RH) is far drier than a South Texas summer night, which routinely runs 80–95% RH. The paper’s own humid case does not reach South Texas conditions, so its “radiative cooling holds up okay” conclusion does not extrapolate cleanly to the Gulf Coast.
Why it matters for this archive
Provides real experimental grounding (not just theory) for how radiative cooling degrades with humidity, and a direct point of comparison against evaporative cooling — a design alternative worth weighing for a humid-climate build. See Night-sky radiative cooling § Climate dependency.