Fig. 1: Schematic description of the passive isothermal film.

a Configuration of the system consisting of radiative cooling and water desorption-driven endothermic reaction (WD-ER) layers for arid climates. b Theoretical cooling and heating power to maintain an isotherm of 25 °C throughout a full day. c Cooling mechanism during daylight hours. d Heating mechanism during nighttime. PDMS and MIL-101(Cr) represent the polydimethylsiloxane and chromium(III) terephthalate metal-organic frameworks, respectively.