Fig. 7: Net cooling power of the PMMAHPA film during the midday.
From: A structural polymer for highly efficient all-day passive radiative cooling
a Schematic of the basic principles of PDRC. When used in a building roof or external siding, the PMMAHPA film exhibits high solar reflectance and high infrared emissivity. b Two-dimensional schematic drawing of the thermal box apparatus with a feedback-controlled heater. The heater maintains the sample surface temperature at that of the ambient environment, minimizing convective and conductive heat losses. c Photo of the experimental apparatus on a rooftop in Shanghai, China. d Temperature tracking of the ambient and the PMMAHPA film under solar intensity of ~ 900 W/m2 and relative humidity of ~ 44% on April 23, 2020. e Continuous measurement of the radiative cooling power of the PMMAHPA film during the midday.
