Passive cooling with natural frustules delivering daily average cooling power exceeding 225 W/m2
Journal
Applied Thermal Engineering
Journal Volume
298
Start Page
131070
ISSN
13594311
Date Issued
2026-06
Author(s)
Abstract
We demonstrate that diatomaceous earth (DE), a natural, durable, and eco-friendly material, can achieve an average daily cooling power exceeding 225 W/m2 through the hybrid radiative and evaporative cooling effects. The intrinsic micro/nanoporous structures of DE, combined with its hydrophilic ceramic composition, endow DE with an excellent water-retention capacity and sustained-release evaporation properties. After thermal treatment, DE exhibits a favorable radiative cooling ability and outstanding water absorption properties. The excellent water retention capacity and sustained-release evaporation mechanism enabled the DE to remain moist for 44 h under outdoor conditions. DE offers temperature reduction by approximately 22.7 °C relative to the building material during daytime and provides sub-ambient cooling by 3.1 °C–6.4 °C relative to open surroundings at night. DE can offer an annual cooling energy of 8.5 × 1010–2.0 × 1011 kJ in cities with different climates and annual precipitation, thus outperforming state-of-the-art passive cooling materials by 1.2–2.5 times. As a natural, durable, low-cost, and non-polluting material, DE is a viable option for passive cooling technology in large-scale applications.
Subjects
all-day passive cooling
daytime radiative cooling
diatomaceous earth
evaporative cooling
natural materials
sustained-release evaporation
Publisher
Elsevier Ltd
Type
journal article