raw · papers · ingested 2026-07-19
Effect of atmospheric water vapor on radiative cooling performance of different surfaces
Source: https://www.sciencedirect.com/science/article/abs/pii/S0038092X19302282
Journal: Solar Energy, published March 11, 2019.
Key findings
Cooling power decreases by 86.6 W/m² with increasing total water vapor column. As total water vapor column rises from 0 to 7,000 atm-cm, average effective emissivity falls from 79.5% to 35.3% — a 44.2% decrease. A metafoam radiative-cooling material was measured reducing average temperature by 5.2°C (day) and 10.2°C (night) under the tested conditions.
The critical comparative data point (surfaced via search-result snippet — full text is paywalled, and this specific figure should be treated as needing independent re-verification before being cited as settled fact): a radiative cooling surface ran 6–7°C ABOVE ambient in humid subtropical Hong Kong (absolute humidity ~16 g/m³), versus 4.9°C BELOW ambient in dry Stanford, CA (absolute humidity ~10 g/m³). South Texas summer absolute humidity commonly exceeds 16 g/m³, putting it in or beyond the Hong Kong regime.
Why it matters for this archive
If this Hong Kong/Stanford comparison holds, a radiative-cooling surface in South Texas summer humidity could become a net heat source rather than a cooling mechanism — precisely the opposite of what the archive’s New Mexico-derived physics assumes. This is the single most consequential finding for any attempt to build a Double Play-style passive cooler outside an arid climate. See Night-sky radiative cooling § Climate dependency.