Temperature reduction and energy-saving analysis in grain storage: Field application of radiative cooling technology to grain storage warehouse

Radiative cooling technology dissipates heat to outer space through the atmospheric window. A radiative cooling membrane possessing spectrum-selective optical properties has been installed on the grain storage warehouses in Hangzhou, China for a field testing. The long-term measurement results show notable decreases in headspace temperature and grain temperature by as much as 9.8 °C and 4 °C, respectively. A building model is created with measurement data and extended to seven grain storage ecological zones to assess potential electricity savings and temperature reductions without air conditioning. For cases with air conditioners, a total electricity saving of 573 GWh/yr is expected if applied nationwide. Without air conditioners, the temperature could decrease by 5.1–9.9 °C and 3.8–6.9 °C for headspace and grain respectively when ambient temperature exceeds 25 °C, thus upgrading the grain storage levels in different grain storage ecological zones. The linear correlation between the cooling-degree-day values set at 18 °C and the electricity consumption was developed, and extended to a global map. It reveals that in areas with values less than 1000 °C d, radiative cooling technology can maintain quasi-low storage temperatures, eliminating the need for air conditioning.