Idemitsu Energy Solutions Achieves Maximum 31.7% Reduction in AC Power Consumption with Radiative Cooling Paint 'Radi-cool'

Idemitsu Energy Solutions Co., Ltd. (Headquarters: Chiyoda-ku, Tokyo) and Radi-cool Japan Co., Ltd. (Headquarters: Chuo-ku, Tokyo) are pleased to announce the results of a demonstration project regarding the energy-saving performance of the radiative cooling paint "Radi-cool" conducted at the "Hakata Port Bayside Museum" in Fukuoka City. In this project, it was confirmed that air conditioning power consumption was reduced by a maximum of 31.7% under strict meteorological comparison conditions (described later).

▲ Appearance before and after painting the roof of Hakata Port Bayside Museum

Background and purpose of the demonstration project Fukuoka City has set a challenge goal of achieving net-zero greenhouse gas emissions by FY2040, and is promoting reductions in energy usage and greenhouse gas emissions at public and private facilities. Since the port area has many buildings with structures susceptible to sunlight, we verified the energy-saving effect through this project and conducted a demonstration project as an initiative toward decarbonization.

Main results of the demonstration project: Confirming the correlation between temperature control and power reduction From the results of this project, a maximum reduction of 34.3°C in roof surface temperature and a maximum reduction of 9.7°C in attic space temperature were confirmed. Furthermore, regarding air conditioning power consumption, when compared under the same meteorological conditions (global solar radiation ±0.3 MJ/day, maximum temperature difference less than ±1.0°C), a maximum reduction of 31.7% and an average reduction of 18.1% (5 cases) were confirmed before and after painting.

▲ Roof surface temperature measurement status before and after painting (thermo camera)

▲ Roof surface temperature measurement status before and after painting (thermo camera)