"Fins" along the building's walls are designed to channel the prevailing north-east winds into the building. Wind tunnel tests conducted at the National University of Singapore found that the "fins" would enhance the air flow by 20 to 30%. Sunshades over the windows protect patients from the direct glare of sunlight. The shades also re-direct light towards the ceiling to enhance the brightness of the wards and save on the use of energy. Large fans in public areas are powered by solar panels on the roof. The air-conditioning system draws supply air from its internal courtyards, where the air is cooler, hence reducing the cooling loads.