Ceiling fan
A ceiling fan is a mechanical fan mounted on the ceiling of a room or space, usually electrically powered, suspended from the ceiling of a room, that uses hub-mounted rotating blades to circulate air. Ceiling fans typically rotate more slowly than other types of circulating fans, such as electric desk fans. They cool people effectively by introducing slow movement into the otherwise still, hot air of a room. Fans never actually cool air, unlike air-conditioning equipment, they in fact heat the air due to the waste heat from the motor and friction, but use significantly less power (cooling air is thermodynamically expensive). Conversely, a ceiling fan can also be used to reduce the stratification of warm air in a room by forcing it down to affect both occupants' sensations and thermostat readings, thereby improving climate control energy efficiency.
Khoo Teck Puat Hospital
"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.