Solar chimney combined with passive evaporative cooler applied on glazing surfaces -

Abstract

This study investigates the performance of a hybrid system applied on glazing surfaces in reducing the space cooling load and radiation asymmetry. The proposed system combines the principles of passive evaporative cooling with the natural buoyant flow in solar chimneys to entrain outdoor air and attenuate the window surface temperature. A predictive mathematical heat and mass model combining the evaporative cooler, glazing section, solar chimney and an office space is developed to study the performance of the proposed system in harshly hot climates. The developed model was validated through experiments conducted in a twin climatic chamber for certain temperature, humidity and solar radiation conditions. Good agreement was found between the measured and predicted temperatures and thermal loads where the maximum discrepancy was to 4.3percent. The proposed system is applied in a case study on a typical office space to analyze its effectiveness in terms of decreasing the window temperature, and subsequently the space load and radiation asymmetry, while maintaining the indoor conditions and requirements. Results have shown that the system was capable of reducing the space load by 19.4percent and attenuating the radiation asymmetry significantly during the working hours of the day for office spaces having window-to-wall ratios of 40percent in Riyadh, KSA. The system performance diminished when applied in locations suffering from humid weather climates.