Thermal Analysis of an Object with Large Surface Area Under Controlled Conditions Regarding Radiative Sky Cooling and with High Emissivity in the 8-13 mM Wavelength Range
Peesapati Venkata Rangacharyulu1,Kiran Kumar Chittiboyina2
1Assistant Professor, Mechanical Engineering Department & Visakha Institute of Engineering and Technology
2Assistant Professor, Mechanical Engineering Department & Visakha Institute of Engineering and Technology
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Abstract - Radiative Sky cooling is an eco-friendly method of using the deep sky as a heat sink and transferring heat into space with a specific wavelength of 8-13 mm (atmospheric window), which is ideal for penetrating the atmosphere by avoiding scattering and total internal reflection in it. Because space acts as a sink, any object emitting heat in those wavelengths acts as a source. As a result, no external energy is required to cool the material. Though the average temperature of the outer sky is 3K, the effective sky temperature is affected by atmospheric factors such as humidity, air temperature, sky clearness etc. In this case, the emitter has been precoated with a specific radiative paint that allows high emissivity of the object in target wavelengths. The effectiveness of surface geometry on this radiative heat transfer is studied in various temperatures and humidity conditions under clear sky also conductive and convective modes of heat transfer and dust in the air are neglected. The view factor is considered along with the surface roughness for comparison. The results of simulation of a corrugated sheet with high relatable high surface area is compared with published results of an experimental model. The surface emissivity is maintained same as that of the experimental model. The behaviour of the both models at different conditions are noted and correlated.
Keywords: Radiative Sky Cooling, Atmospheric Window, Specific Emissivity, Ziblod condensers, Dew harvesting, Nocturnal cooling, space cooling, Spectral emission, Total Heat Flux
