A pure radiant cooling device for “air conditioning” without conditioning air

Ever since the birth of the first air conditioner (Carrier air conditioner) in 1902, over one hundred years ago, it has been accompanied by several technical problems, e.g., (1) low energy efficiency in large open spaces, (2) spread of pollutants, airborne pandemic transmission (e.g., severe acute respiratory syndrome [SARS], COVID-19) through air-conditioning systems, and (3) low comfort caused by fan noise and blowing sounds. Here, we report a personalized pure radiant cooling device that decouples the fresh air supply from space cooling to achieve air conditioning without conditioning the air. Condensation-free radiant cooling with a radiant cooling capacity of 152 W/m² is achieved with a polyethylene (PE) film-covered super-cold infrared-emissive surface. By optimizing the design and operation parameters, the device saves up to 50.4% of cooling energy in a typical summer building environment. Our concept opens up the possibility of pandemic-free personalized thermal management with high energy efficiency and thermal comfort.