Desiccant enhanced nocturnal radiative cooling-solar collector system for air comfort application in hot arid areas

In this study, the feasibility of implementing desiccant enhanced nocturnal radiative cooling-solar collector system for air comfort application in hot arid areas of Upper Egypt is carried out using the analytical techniques. The system is investigated based on a daily cycle one-way airflow direction and the measured weather data. In addition, a mathematical model for analyzing the heat and mass transfer in the system during adsorption (nighttime mode) and regeneration (daytime mode) is established. The obtained results were verified with correspondent experiments and a good agreement existed. Thereafter, the model is used to investigate the system feasibility for air comfort application. It is found that this system can be used in hot arid areas of Upper Egypt at which the ambient air relative humidity is very low in summer daytime and gradually increases during nighttime that makes utilization of this system effective. Also, the model is used to investigate the effect of the air mass flow rate on this system performance and the results show that, it is preferred to use a low air mass flow rate in order to obtain a lower outlet air temperature which is less than the ambient air by 5.5–7 °C and below 40% relative humidity.