Use of Building Façade for Active Indoor Humidity Control

Abstract

Regulating indoor humidity levels to healthy ranges is important to provide occupants with acceptable thermal comfort and air quality conditions. Conventional techniques relied on the supply of dehumidified outdoor air to dilute the indoor generated moisture. They use vapor compression cooling either as standalone system or integrated with desiccant dehumidifiers to generate the dry air. Such systems are energy intensive and require large footprint areas, especially in hot and humid climates. This work proposes thus an energy-efficient alternative where the indoor humidity is pumped directly from the space and discharged outdoors. This system integrates a metal organic framework-based dehumidifier with the building breathable façade. The dehumidifier dries the outdoor air that is used to ventilate the façade and create the necessary driving gradient for the moisture transfer, irrespective of the outdoor air conditions. Mathematical models are developed to evaluate the system performance for an office space located in the extreme hot and humid climate of Jeddah, KSA. The proposed system resulted in 89 % and 90 % reduction in the system size and energy consumption compared to conventional systems over the peak humidity month.