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.
Electrostatic fluid accelerator
Potential advantages of EFA cooling devices include improvement on all these issues; EFA fans produce no vibration and have no parts to wear out. Their power consumption and airflow are controllable electronically, allowing them to be run in an optimal fashion to maximize cooling and efficiency. In particular, EFA fans can produce flow which is fairly laminar, and the velocity profile of the flow can be controlled to a much greater extent than conventional fans.
Control of the airflow may have the most important impact on cooling effectiveness. Electrostatically accelerated flows have been shown experimentally to alter the boundary layer along a fixed surface so that the heat transfer rate is increased, in some cases by more than twofold.