Radiative cooling as low-grade energy source: A literature review

Abstract

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Energy Savings Potential of a Novel Radiative Cooling and Solar Thermal Collection Concept in Buildings for Various World Climates

“…This concept produces heat and cold in the same manner as two separated devices would do. Similar devices already tested in the literature were designed to produce either heat or cold and, without any modification of the original device, the other service was studied ,,. The RCE concept is conceived since the beginning to produce both.…”

“…Lot of research has been conducted in the study of the radiative cooling phenomenon, and, more recently, in the development of radiative cooling experimental prototypes and numerical/theoretical models. A comprehensive review of radiative cooling is presented in . The research conducted in, used unglazed solar collectors to test the radiative cooling achievable with a simple modification, showing the capability of cooling production.…”

“…Radiative cooling phenomenon is antagonist to solar thermal collection, mainly due to the different radiation wavelength used (longwave radiation for radiative cooling and shortwave radiation for solar thermal collection) and because solar thermal collection takes place during sunlight hours while radiative cooling mainly when there is no sunlight. A more detailed analysis of the differences between these two technologies is presented in …”

Deferred Cooling System for Desert Climates

“…Clouds can increase incoming infrared atmospheric radiation considerably because they can act as a blackbody that emits radiation near the infrared window. 1 As early as 1978, Atwater and Ball 2 created a method to compute infrared radiation fluxes and effective sky temperature. They mapped sky temperature and difference between surface and sky temperatures over the United States for different seasons of the year.…”

“…A world map showing locations where cooling needs can be met by radiative cooling is still missing. 1 Suppose that, through the use of selective materials, we could create an ideal emitter in the 8-13 mm atmospheric window and an ideal reflector outside this range, then cooling power at ambient temperature could reach up to 100 W/m 2 ; theoretically, this could result in cooling of about 50°C below ambient temperature if radiation energy was the sole energy affecting the perfect emitter. 5 Though such a material does not yet exist, there are ongoing efforts to create conditions that would get radiative cooling to operate as closely as possible to ideal conditions.…”