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.
Helicoidal Skyscraper
The Helicoidal Skyscraper can be considered a sustainable building or an example of the green architecture concept due to several aspects of its design. As a tall building, for instance, it addresses the energy problem by minimising the quantities of materials needed for its construction. Also, its unique logarithmic spiral would have reacted to the wind with a vertical force that drives it upwards, taking with the air pollution - out from the streets below. It avoids the capability of most tall buildings to serve as obstructions that affect the atmospheric circulation and the dispersion of pollutants. There is an expectation of the so-called "chimney effect," which eliminates the creation of an unpleasant micro-climate and the accumulation of pollution in the lower strata of the urban atmosphere by increasing the conviction currents created by the thermal distribution of solar heat on the external surfaces of the tower.