Proceedings of the 27th National and 5th International ISHMT-ASTFE Heat and Mass Transfer Conference December 14-17, 2023, IIT Patna, Patna-801106, Bihar, India
Energy, Exergy, and Economic Assessments of Sky Radiative Cooling System
Resumo
In the modern era, cooling systems are essential for almost
every building, often relying on active cooling powered by
non-renewable fossil fuels. However, there is a promising
alternative to partially replace active cooling with natural
environmental conditions for achieving comfort. This study
aims to explore the relationship between radiative cooling
power and the temperature difference between the ambient
environment and the sky. The research analyses energy parameters, such as radiative cooling power and radiative
efficiency, while considering variations in ambient temperature, relative humidity, and emissivity of the radiative
cooler surface. The results show that an increase in ambient
temperature and emissivity leads to higher radiative
efficiency, ranging from 20-30%, while relative humidity has a negative impact on radiative efficiency. The exergy
efficiency decreases from 21% to 2% as the heater tank
temperature and ambient temperature increase, but it increases
from 2% to 21% as the radiative cooler temperature decreases. With higher ambient temperature and relative humidity, the required surface area for cooling also increases, resulting in an elevated Total Annualized Cost (TAC) of the system from 3$/h to 6$/h. However, due to the higher emissivity, the surface area requirement for cooling decreases, leading to a reduced TAC from 5.8$/h to 4.87$/h.