Evaporatively-cooled facade integrated with photovoltaic thermal panel applied in hot and humid climates

Abstract

This study investigates the performance of a hybrid passive cooling system, applied on fully-glazed facades of typical office spaces, in reducing the facade surface temperature and the space thermal loads. The proposed system consists of a Photovoltaic Thermal (PVT) panel, evaporative cooler, evaporatively-cooled facade, a fan and a pump, to forcefully cool hot outdoor air and attenuate the facade surface temperature. The physical design of the evaporative cooler in the system overcomes the problem of its limited performance in humid weathers. A predictive heat and mass transport model combining the system subcomponents was developed and integrated with a space model. An experimental validation was then carried out on the space model with and without the integrated system to evaluate its ability in representing real life conditions; good agreement was found between the model and experiment as the maximum discrepancies in the hourly facade surface temperatures and space loads were 6.0% and 12.2%, respectively. The proposed system was then applied in a case study on a typical office space in Doha Qatar, mimicking a country with harshly hot and humid weather conditions. During on summer representative day, the application of the system was able to moderate the facade temperature and space load throughout the day and yield 14.5% savings in the space daily total thermal energy demand.