Monday, February 10, 2014

Wind Towers

By Sufiyanu Momoh

Wind towers are architectural elements rising from homes, used to capture cooler air prevailing at a higher distance from the ground into the interior of the house to cool the house. It is mainly used in residential buildings in the Middle East.

In the United Arab Emirate, almost all the building have air conditioners so the function of the wind towers are no longer needed. These wind towers were essential in times were houses were built out of date palm leaves.  Even though these wind towers are no longer a necessity in most residential houses today, it is considered as a local identity in this area and still used as architecture elements in some buildings.

In a lot of countries around the Middle East these wind towers have been described as wind catchers. It is not known exactly where it was first originated although there has been claims that it was originated in Iran.

These towers traditionally have four openings on four sides with an "X" in the middle which helps channel wind from its prevailing direction down the tower. Air flows down to the interior and acts as an air cooler and flows out through different directions as more air enters from the prevailing wind direction.

In an area without wind, these wind towers function as thermal chimney that uses convection of air heated by passive solar energy. It creates a pressure gradient which allows less dense hot air to travel upwards and escape out the top.  This is also affected by the day-night circle of air, trapping cool air below. The temperature in these area can't drop below the nightly low temperature. This method offered comfortable indoor conditions at zero cost to the environment and the user.

These same techniques for cooling are being used today.  Architecture in the Middle East has matured and changed over time due to its hot climate.

With the advancement of building methods and technologies, these systems have been phased out in favor of mechanical systems consuming large amounts of energy.  Although, this customary method has been developed and applied to up to date equivalents, with substantial success in Europe, where the climate is less susceptible to large warmth variations. The wind towers are designed to match the design of the building, but function in identical way, confining air at high level and delivering to the inhabitants underneath.

The wind tower comprises an interior structure that divides the duct into quadrants, therefore providing a delivery flow irrespective of breeze direction. The residual quadrants are utilized as exhaust chambers for used air just as described above. This method benefits solar-driven internal fans to ensure a consistent stream of ventilated air, and therefore power utilization is zero.

Wind towers have come a long way from what they used to be in the Middle East to this still functioning, cost effective cure to desert heat. they are still being used today, providing a better, more confortable living condition in the arid climate of modern day Iran and the surrounding areas.

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