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A windcatcher, wind tower, or wind scoop ( ar, برجيل ; fa, بادگیر) is a traditional architectural element used to create cross ventilation and
passive cooling Passive cooling is a building design approach that focuses on heat gain control and heat dissipation in a building in order to improve the indoor thermal comfort with low or no energy consumption. This approach works either by preventing heat from ...
in buildings. Windcatchers come in various designs: unidirectional, bidirectional, and multidirectional. Windcatchers are widely used in North Africa and
West Asia Western Asia, West Asia, or Southwest Asia, is the westernmost subregion of the larger geographical region of Asia, as defined by some academics, UN bodies and other institutions. It is almost entirely a part of the Middle East, and includes ...
. Iran, especially in the south of Fars province and Hormozgan province, and other countries around the
Persian Gulf The Persian Gulf ( fa, خلیج فارس, translit=xalij-e fârs, lit=Gulf of Fars, ), sometimes called the ( ar, اَلْخَلِيْجُ ٱلْعَرَبِيُّ, Al-Khalīj al-ˁArabī), is a mediterranean sea in Western Asia. The bo ...
have used windcatchers for the past three thousand years. Neglected by modern architects in the latter half of the 20th century, the early 21st century saw them used again, to increase ventilation and cut power demand for air-conditioning. Generally, the cost of construction for a windcatcher-ventilated building is less than that of a similar building with conventional
heating, ventilation, and air conditioning Heating, ventilation, and air conditioning (HVAC) is the use of various technologies to control the temperature, humidity, and purity of the air in an enclosed space. Its goal is to provide thermal comfort and acceptable indoor air quality ...
(HVAC) systems. The maintenance costs are also lower. Unlike powered air-conditioning and fans, windcatchers are silent and continue to function when the
electrical grid An electrical grid is an interconnected network for electricity delivery from producers to consumers. Electrical grids vary in size and can cover whole countries or continents. It consists of:Kaplan, S. M. (2009). Smart Grid. Electrical Power ...
power fails (a particular concern in places where grid power is unreliable and expensive). Windcatchers rely on local weather and
microclimate A microclimate (or micro-climate) is a local set of atmospheric conditions that differ from those in the surrounding areas, often with a slight difference but sometimes with a substantial one. The term may refer to areas as small as a few squ ...
conditions, and not all techniques will work everywhere; local factors must be taken into account in design.


Structure and function

Windcatchers vary dramatically in shape, including height, cross-sectional area, and internal sub-divisions and filters. Windcatching has gained some ground in Western architecture, and there are several commercial products using the name ''windcatcher''. Some modern windcatchers use sensor-controlled moving parts or even solar-powered fans to make semi- passive ventilation and semi-
passive cooling Passive cooling is a building design approach that focuses on heat gain control and heat dissipation in a building in order to improve the indoor thermal comfort with low or no energy consumption. This approach works either by preventing heat from ...
systems. Windscoops have long been used on ships, in the form of a
dorade box A dorade box (also called a dorade vent, collector box, or simply a "ventilator") is a type of vent that permits the passage of air in and out of the cabin or engine room of a boat while keeping rain, spray, and sea wash out. Design The basic for ...
. Windcatchers have also been used experimentally to cool outdoor areas in cities, with mixed results; traditional methods include narrow, walled spaces, parks and winding streets, which act as cold-air reservoirs, and takhtabush-like arrangements (see sections on night flushing and convection, below).


Prevailing wind conditions

The construction of a windcatcher depends on the
prevailing wind In meteorology, prevailing wind in a region of the Earth's surface is a surface wind that blows predominantly from a particular direction. The dominant winds are the trends in direction of wind with the highest speed over a particular point o ...
direction at that specific location: if the wind tends to blow from only one side, it may have only one opening, and no internal partitions. In areas with more variable wind directions, there may also be radial internal walls, which divide the windtower into vertical sections. These sections are like parallel
chimney A chimney is an architectural ventilation structure made of masonry, clay or metal that isolates hot toxic exhaust gases or smoke produced by a boiler, stove, furnace, incinerator, or fireplace from human living areas. Chimneys are typ ...
s, but with openings to the side, pointing in multiple directions. More sections reduce the flow rate, but increase the efficiency at suboptimal wind angles. If the wind hits the opening square-on, it will go in, but if it hits it at a sufficiently oblique angle, it will tend to slip around the tower, instead. Windcatchers in areas with stronger winds will have smaller total cross-sections, and areas with very hot wind may have many smaller shafts in order to cool the incoming air. Windtowers with square horizontal cross-sections are more efficient than round ones, as the sharp angles make the flow less laminar, encouraging flow separation; suitable shaping increases suction. Taller windcatchers catch higher winds. Higher winds blow stronger and
cooler A cooler, portable ice chest, ice box, cool box, chilly bin (in New Zealand), or esky ( Australia) is an insulated box used to keep food or drink cool. Ice cubes are most commonly placed in it to help the contents inside stay cool. Ice packs a ...
(and in a different direction). Higher air is also usually less dusty. If the wind is dusty or polluted, or there are insect-borne illnesses such as
malaria Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. ...
and
dengue fever Dengue fever is a mosquito-borne tropical disease caused by the dengue virus. Symptoms typically begin three to fourteen days after infection. These may include a high fever, headache, vomiting, muscle and joint pains, and a characteristic ...
, then
air filter A particulate air filter is a device composed of fibrous, or porous materials which removes solid particulates such as dust, pollen, mold, and bacteria from the air. Filters containing an adsorbent or catalyst such as charcoal (carbon) may a ...
ing may be necessary. Some dust can be dumped at the bottom of the windcatcher as the air slows (see diagram below), and more can be filtered out by suitable plantings or insect mesh. Physical filters generally reduce throughflow, unless the flow is very gusty. It may also be possible to fully or partially close the windcatcher off. The short, wide right-triangle-prism are usually bidirectional, set in symmetrical pairs, and are often used with a (evaporative cooling unit) and a (
roof lantern A roof lantern is a daylighting architectural element. Architectural lanterns are part of a larger roof and provide natural light into the space or room below. In contemporary use it is an architectural skylight structure. A lantern roof wil ...
vent). Wide s are more often used in damper climates, where high-volume air flow is more important compared to evaporative cooling. In hotter climates, they are narrower, and air is cooled on its way in. They are more commonly used in Africa. , on the other hand, are multisided (usually 4-sided), and they are typically tall towers (up to 34 meters tall) which can be closed in winter. They are more common in the Persian Gulf region and in areas with
dust storm A dust storm, also called a sandstorm, is a meteorological phenomenon common in arid and semi-arid regions. Dust storms arise when a gust front or other strong wind blows loose sand and dirt from a dry surface. Fine particles are transp ...
s. Taller windcatchers also have a stronger stack effect.


Cooling methods

Night-flushing cools the house by increasing ventilation at night, when the outdoor air is cooler; windtowers can assist night flushing. A windcatcher can also cool air by drawing it over cool objects. In
arid climate The desert climate or arid climate (in the Köppen climate classification ''BWh'' and ''BWk''), is a dry climate sub-type in which there is a severe excess of evaporation over precipitation. The typically bald, rocky, or sandy surfaces in deser ...
s, the daily temperature swings are often extreme, with desert temperatures often dipping below freezing at night. The
thermal inertia In thermodynamics, a material's thermal effusivity, thermal inertia or thermal responsivity is a measure of its ability to exchange thermal energy with its surroundings. It is defined as the square root of the product of the material's thermal ...
of the soil evens out the daily and even annual temperature swings. Even the thermal inertia of thick masonry walls will keep a building warmer at night and cooler during the day. Windcatchers can thus cool by drawing air over night- or winter-cooled materials, which act as heat reservoirs. Windcatchers that cool by drawing air over water use the water as a heat reservoir, but if the air is dry, they are also cooling the air with
evaporative cooling An evaporative cooler (also known as evaporative air conditioner, swamp cooler, swamp box, desert cooler and wet air cooler) is a device that cools air through the evaporation of water. Evaporative cooling differs from other air conditioning ...
. The heat in the air goes into evaporating some of the water, and will not be released until the water re-condenses. This is a very effective way of cooling dry air. Simply moving the air also has a cooling effect. Humans cool themselves using evaporative cooling when they
sweat Perspiration, also known as sweating, is the production of fluids secreted by the sweat glands in the skin of mammals. Two types of sweat glands can be found in humans: eccrine glands and apocrine glands. The eccrine sweat glands are distrib ...
. A draft disrupts the
boundary layer In physics and fluid mechanics, a boundary layer is the thin layer of fluid in the immediate vicinity of a bounding surface formed by the fluid flowing along the surface. The fluid's interaction with the wall induces a no-slip boundary cond ...
of body-warmed and water-saturated air clinging to the skin, so a human will feel cooler in moving air than in stagnant air of the same temperature.


Airflow forces

The windcatcher can function in two ways: directing airflow using the pressure of wind blowing into the windcatcher, or directing airflow using
buoyancy force Buoyancy (), or upthrust, is an upward force exerted by a fluid that opposes the weight of a partially or fully immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus the pr ...
s from
temperature gradient A temperature gradient is a physical quantity that describes in which direction and at what rate the temperature changes the most rapidly around a particular location. The temperature gradient is a dimensional quantity expressed in units of degre ...
s ( stack effect). The relative importance of these two forces has been debated. The importance of windpressure obviously increases with increasing wind speed, and is generally more important than buoyancy under most conditions in which the windcatcher is working effectively. Airflow speed is also important, especially for evaporative cooling (since it only works on dry air, and humidifies the air). It is possible for a windtower-ventilated building to have very high flow rates; 30 air changes per hour were measured in one experiment. Uniform, stable flow with no stagnant corners is important. Turbulent flow should therefore be avoided;
laminar flow In fluid dynamics, laminar flow is characterized by fluid particles following smooth paths in layers, with each layer moving smoothly past the adjacent layers with little or no mixing. At low velocities, the fluid tends to flow without lateral mi ...
is more effective at maintaining human comfort (for an extreme example, see
Tesla valve A Tesla valve, called a valvular conduit by its inventor, is a fixed-geometry passive check valve. It allows a fluid to flow preferentially in one direction, without moving parts. The device is named after Nikola Tesla, who was awarded in 1920 ...
). Other elements are often used in combination with the windcatchers to cool and ventilate:
courtyards A courtyard or court is a circumscribed area, often surrounded by a building or complex, that is open to the sky. Courtyards are common elements in both Western and Eastern building patterns and have been used by both ancient and contemporar ...
,
dome A dome () is an architectural element similar to the hollow upper half of a sphere. There is significant overlap with the term cupola, which may also refer to a dome or a structure on top of a dome. The precise definition of a dome has been a m ...
s, walls, and fountains, for instance, as integral parts of an overall ventilation and heat-management strategy.


Wind pressure

If a windcatcher's open side faces the prevailing wind, it can "catch" it, and bring it down into the heart of the building. Suction from the lee side of a windtower is also an important driving force, usually somewhat more constant and less gusty than the pressure on the upwind side (see
Venturi effect The Venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section (or choke) of a pipe. The Venturi effect is named after its discoverer, the 18th century Italian physicist, Giovanni Battista ...
and
Bernoulli's principle In fluid dynamics, Bernoulli's principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in static pressure or a decrease in the fluid's potential energy. The principle is named after the Swiss mathematici ...
). Routing the wind through the building cools the people in the building interior. The air flows through the house, and leaves from the other side, creating a through-draft; the rate of airflow itself can provide a cooling effect. Windcatchers have been employed in this manner for thousands of years. The windtower essentially creates a pressure gradient to draw air through the building. Windtowers topped with horizontal airfoils have been built to enhance these pressure gradients. The shape of the traditional roof also creates suction as wind blows over it.


Convection

Buoyancy is usually not the main effect driving windcatcher air circulation during the day. In a windless environment, a windcatcher can still function using the stack effect. The hot air, which is less dense, tends to travel upwards and escape out the top of the house via the windtower. Heating of the windtower itself can heat the air inside (making it a solar chimney), so that it rises and pulls air out of the top of the house, creating a draft. This effect can be enhanced with a heat source at the bottom of the windtower ( such as humans, ~80 Watts each), but this heats the house and makes it less comfortable. A more practical technique is to cool the air as it flows down and in, using heat reservoirs and/or evaporative cooling. A takhtabush is a space similar to the ancient Roman tablinum, opening both onto a heavily shaded courtyard and onto a rear garden court (the garden side being shaded with a lattice). It is designed to capture a cross-draft. The breeze is at least partly driven by convection (since one court will generally be warmer than the other), and may also be driven by wind pressure and evaporative cooling, so the garden and courtyard are used as windcatchers. Buoyancy forces are used to cause night flushing.


Night flushing (colder air)

The
diurnal temperature cycle In meteorology, diurnal temperature variation is the variation between a high air temperature and a low temperature that occurs during the same day. Temperature lag Temperature lag is an important factor in diurnal temperature variation: peak da ...
means that the night air is colder than the daytime air; in arid climates, much colder. This creates appreciable buoyancy forces. Buildings may be designed to spontaneously increase ventilation at night. Courtyards in hot climates fill with cold air at night. This cold air then flows from the courtyard into adjacent rooms. The cold night air will flow in easily, as it is more dense than the rising warm air it is displacing. But in the day, the courtyard walls and awning shade it, while the air outside is heated by the sun. The cool masonry will also chill the nearby air. The courtyard air will become stably stratified, the hot air floating on top of the cold air with little mixing. The fact that the openings are at the top will trap the cool air below, though it cannot cause the temperature to drop below the nightly minimum temperature. This mechanism also works in windtowers.


Subterranean cooling

A windcatcher can also cool air by bringing into contact with cool
thermal mass In building design, thermal mass is a property of the mass of a building that enables it to store heat and provide inertia against temperature fluctuations. It is sometimes known as the thermal flywheel effect. The thermal mass of heavy structura ...
es. These are often found underground. Below approximately 6m of depth, soil and
groundwater Groundwater is the water present beneath Earth's surface in rock and Pore space in soil, soil pore spaces and in the fractures of stratum, rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit ...
is always at about the annual mean-average temperature (MATT) (it is this depth which is used for many ground-source heat pumps, often loosely referred to as "geothermal heat pumps" by laypeople The author issued an of this article in February 2001.). The
thermal inertia In thermodynamics, a material's thermal effusivity, thermal inertia or thermal responsivity is a measure of its ability to exchange thermal energy with its surroundings. It is defined as the square root of the product of the material's thermal ...
of the soil evens out the daily and even annual temperature swings. In
arid climate The desert climate or arid climate (in the Köppen climate classification ''BWh'' and ''BWk''), is a dry climate sub-type in which there is a severe excess of evaporation over precipitation. The typically bald, rocky, or sandy surfaces in deser ...
s, the daily temperature swings are often extreme, with desert temperatures often dipping below freezing at night. Even the thermal inertia of thick masonry walls will keep a building warmer at night and cooler during the day; in hot-arid climates, thick walls with high
thermal mass In building design, thermal mass is a property of the mass of a building that enables it to store heat and provide inertia against temperature fluctuations. It is sometimes known as the thermal flywheel effect. The thermal mass of heavy structura ...
(
adobe Adobe ( ; ) is a building material made from earth and organic materials. is Spanish for '' mudbrick''. In some English-speaking regions of Spanish heritage, such as the Southwestern United States, the term is used to refer to any kind of ...
, stone,
brick A brick is a type of block used to build walls, pavements and other elements in masonry construction. Properly, the term ''brick'' denotes a block composed of dried clay, but is now also used informally to denote other chemically cured cons ...
) are common (though thinner walls with high resistance against heat transmission are more modernly sometimes used). Windcatchers can thus cool by drawing air over night- or winter-cooled materials, which act as heat reservoirs. Windcatchers are also often used to ventilate lower-level indoor spaces (e.g.
shabestan A shabestan or shabistan ( fa, ; Old Persian ''xšapā.stāna'') is an underground space that can be usually found in traditional architecture of mosques, houses, and schools in ancient Iran. These spaces were usually used during summers and coul ...
s), which maintain frigid temperatures in the middle of the day even without windcatchers. Ice houses are traditionally used to store water frozen overnight in desert areas, or over winter in temperate areas. They may use windcatchers to circulate air into an underground or semi-underground chamber, evaporatively cooling the ice so that it melts only slowly and stays fairly dry (see lede image). At night, the windcatchers may even bring sub-freezing night air underground, helping to freeze ice.


Evaporative cooling

In dry climates, the
evaporative cooling An evaporative cooler (also known as evaporative air conditioner, swamp cooler, swamp box, desert cooler and wet air cooler) is a device that cools air through the evaporation of water. Evaporative cooling differs from other air conditioning ...
effect may be used by placing water at the air intake, such that the draft draws air over water and then into the house. For this reason, it is sometimes said that the fountain, in the architecture of hot, arid climates, is like the fireplace in the architecture of cold climates. Windcatchers are used for evaporative cooling in combination with a
qanat A qanat or kārīz is a system for transporting water from an aquifer or water well to the surface, through an underground aqueduct; the system originated approximately 3,000 BC in what is now Iran. The function is essentially the same across ...
, or underground canal (which also makes use of the subterranean heat reservoir described above). In this method, the open side of the tower faces away from the direction of the prevailing wind (the tower's orientation may be adjusted by directional ports at the top). When only the
leeward Windward () and leeward () are terms used to describe the direction of the wind. Windward is ''upwind'' from the point of reference, i.e. towards the direction from which the wind is coming; leeward is ''downwind'' from the point of reference ...
side is left open, air is drawn upwards using the
Coandă effect The Coandă effect ( or ) is the tendency of a fluid jet to stay attached to a convex surface. ''Merriam-Webster'' describes it as "the tendency of a jet of fluid emerging from an orifice to follow an adjacent flat or curved surface and to en ...
. This pulls air into an intake on the other side of the building. The hot air brought down into the qanat tunnel is cooled by coming into contact with the cool water and / or cool
earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's sur ...
and the cool water running through the qanat. The air is also
evaporatively cooled An evaporative cooler (also known as evaporative air conditioner, swamp cooler, swamp box, desert cooler and wet air cooler) is a device that cools air through the evaporation of water. Evaporative cooling differs from other air conditioning sy ...
when some of the water in the qanat evaporates as the hot, dry surface air passes over it; the heat energy in the air is absorbed as energy of vaporization. The dry air is thus also humidified before entering the building. The cooled air is drawn up through the house and finally out the windcatcher, again by the Coandă effect. On the whole, the cool air flows through the building, decreasing the structure's overall temperature. A is a type of fountain with a thin sheet of flowing water, shaped to maximize surface area and thus evaporative cooling. Windcatchers are often used with salasabils may be used to maximize the flow of unsaturated air over the water surface and carry the cooled air to where it is needed in the building. Wetted matting can also be hung inside the windcatcher to cool incoming air. This can reduce flow, especially in weak winds. However, it can also produce a downdraft of cool air in windless conditions. The evaporative cooling within a windtower causes the air in the tower to sink, driving circulation. This is called passive downdraught evaporative cooling (PDEC). It may also be generated using spray nozzles (which have a tendency to get blocked if the water is hard) or cold-water cooling coils (like hydronic underfloor heating in reverse).


Regional use


Africa


Egypt

In Egypt windcatchers are known as , pl. . They are generally shaped as right triangular prisms with the vertical side left open and facing directly up or down wind (one of each per building). They work best if oriented within 10 degrees of wind direction; larger angles allow the wind to escape. Windcatchers were used in traditional
ancient Egyptian architecture Spanning over three thousand years, ancient Egypt was not one stable civilization but in constant change and upheaval, commonly split into periods by historians. Likewise, ancient Egyptian architecture is not one style, but a set of styles diff ...
, and only started to fall out of use in the mid-1900s C.E.. Their use is now being re-examined, as air conditioning accounts for 60% of Egypt's peak electrical power demand (and thus the need for 60% of its generating capacity). Windcatchers in Egypt are often used in conjunction with other passive cooling elements.low-res bw version
/ref> Byggnadskonsten, Fornegyptiska boningshus, Nordisk familjebok.png, Dwelling house in Ancient Egypt with windcatcher. From a painting at the Pharaonic house of Neb-Ammun, Egypt, which dates from the 19th Dynasty, c. 1300 BC (British Museum). Ancient Egyptian House miniature showing windcatchers.jpg, Ancient Egyptian House miniature showing windcatchers, dating from Early Dynastic Period of Egypt, found in Abou Rawsh near Cairo. Now in
Louvre The Louvre ( ), or the Louvre Museum ( ), is the world's most-visited museum, and an historic landmark in Paris, France. It is the home of some of the best-known works of art, including the ''Mona Lisa'' and the '' Venus de Milo''. A central ...
. RPM Ägypten 003.jpg, Model of an Ancient Egyptian house with windcatcher,
Roemer- und Pelizaeus-Museum Hildesheim The Roemer- und Pelizaeus-Museum Hildesheim is an archaeological museum in Hildesheim, Germany. Mostly dedicated to ancient Egyptian and ancient Peruvian art, the museum also includes the second largest collection of Chinese porcelain in Euro ...
صور متنوعة من داخل القلعة 26.jpg, Windcatchers and roofs shading narrow
airshaft In manufacturing, an airshaft is a device used for handling winding reels in the processing of web-fed materials, such as continuous-process printing presses. Airshafts—also called Air Expanding shafts—are used in the manufacturing processes ...
courtyards,
Cairo Citadel The Citadel of Cairo or Citadel of Saladin ( ar, قلعة صلاح الدين, Qalaʿat Salāḥ ad-Dīn) is a medieval Islamic-era fortification in Cairo, Egypt, built by Salah ad-Din (Saladin) and further developed by subsequent Egyptian rule ...
. View over Khartoum.jpg, Windcatchers in
Khartoum Khartoum or Khartum ( ; ar, الخرطوم, Al-Khurṭūm, din, Kaartuɔ̈m) is the capital of Sudan. With a population of 5,274,321, its metropolitan area is the largest in Sudan. It is located at the confluence of the White Nile, flowing n ...
, Sudan


Middle East and Asia

Windcatchers are common feature across many Middle Eastern countries influenced by the spread of culture under Islamic rule.


Iran

In Iran, a windcatcher is called a ''bâdgir'': ''bâd'' "wind" + ''gir'' "catcher" ( fa, بادگیر). The devices were used in
Achaemenid architecture Achaemenid architecture includes all architectural achievements of the Achaemenid Persians manifesting in construction of spectacular cities used for governance and inhabitation ( Persepolis, Susa, Ecbatana), temples made for worship and social ...
. (the English is hard to understancd) In Iran, they are used in the hot, dry areas of the Central Plateau, and in the hot, humid coastal regions. Central
Iran Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmeni ...
shows large
diurnal temperature variation In meteorology, diurnal temperature variation is the variation between a high air temperature and a low temperature that occurs during the same day. Temperature lag Temperature lag is an important factor in diurnal temperature variation: peak da ...
with an
arid climate The desert climate or arid climate (in the Köppen climate classification ''BWh'' and ''BWk''), is a dry climate sub-type in which there is a severe excess of evaporation over precipitation. The typically bald, rocky, or sandy surfaces in deser ...
. Most buildings are constructed from thick
ceramic A ceramic is any of the various hard, brittle, heat-resistant and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcelain, ...
with high insulation values. Towns centered on desert
oases In ecology, an oasis (; ) is a fertile area of a desert or semi-desert environment'ksar''with its surrounding feeding source, the palm grove, within a relational and circulatory nomadic system.” The location of oases has been of critical im ...
tend to be packed very closely together with high walls and ceilings, maximizing shade at ground level. The heat of direct sunlight is minimized with small windows that face away from the sun. The windcatcher's effectiveness had led to its routine use as a refrigerating device in Iran. Many traditional water reservoirs ('' ab anbars''), which are capable of storing water at near freezing temperatures during summer months, are built with windcatchers. The
evaporative cooling An evaporative cooler (also known as evaporative air conditioner, swamp cooler, swamp box, desert cooler and wet air cooler) is a device that cools air through the evaporation of water. Evaporative cooling differs from other air conditioning ...
effect is strongest in the driest climates, such as on the Iranian plateau, leading to the ubiquitous use of windcatchers in drier areas such as
Yazd Yazd ( fa, یزد ), formerly also known as Yezd, is the capital of Yazd Province, Iran. The city is located southeast of Isfahan. At the 2016 census, the population was 1,138,533. Since 2017, the historical city of Yazd is recognized as a Wor ...
,
Kerman Kerman ( fa, كرمان, Kermân ; also romanized as Kermun and Karmana), known in ancient times as the satrapy of Carmania, is the capital city of Kerman Province, Iran. At the 2011 census, its population was 821,394, in 221,389 households, ma ...
,
Kashan Kashan ( fa, ; Qashan; Cassan; also romanized as Kāshān) is a city in the northern part of Isfahan province, Iran. At the 2017 census, its population was 396,987 in 90,828 families. Some etymologists argue that the city name comes from ...
, Sirjan, Nain, and Bam. Windcatchers tend to have one, four, or eight openings. In the city of Yazd, all windcatchers are four- or eight-sided. The construction of a windcatcher depends on the direction of airflow at that specific location: if the wind tends to blow from only one side, it is built with only one
downwind Windward () and leeward () are terms used to describe the direction of the wind. Windward is ''upwind'' from the point of reference, i.e. towards the direction from which the wind is coming; leeward is ''downwind'' from the point of reference ...
opening. This is the style most commonly seen in Meybod, 50 kilometers from Yazd: the windcatchers are short and have a single opening. Windcatchers in Iran may be quite elaborate, due to their use as status symbols. A small windcatcher is called a ''shish-khan'' in traditional Persian architecture. Shish-khans can still be seen on top of ab anbars in
Qazvin Qazvin (; fa, قزوین, , also Romanized as ''Qazvīn'', ''Qazwin'', ''Kazvin'', ''Kasvin'', ''Caspin'', ''Casbin'', ''Casbeen'', or ''Ghazvin'') is the largest city and capital of the Province of Qazvin in Iran. Qazvin was a capital of the ...
and other northern cities in Iran. These seem to function more as ventilators than as the temperature regulators seen in the central deserts of Iran. File:Dolat Abad Garden - Pavilion 02.jpg, The windcatcher of Dowlatabad Garden in
Yazd Yazd ( fa, یزد ), formerly also known as Yezd, is the capital of Yazd Province, Iran. The city is located southeast of Isfahan. At the 2016 census, the population was 1,138,533. Since 2017, the historical city of Yazd is recognized as a Wor ...
,
Iran Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmeni ...
— one of the tallest existing windcatchers File:Borujerdiha.jpg, Borujerdi House, in Kashan, central Iran. Built in 1857, it is an excellent example of ancient Persian desert architecture. The two tall windcatchers cool the ''
andaruni Andaruni ( fa, اندرونی) in Iranian architecture, is the inner quarter where the women lived. It has been described as ''harem'' in Arabic. Private space In traditional Persian residential architecture the ''andaruni'' is a part of the h ...
'' (courtyard) of the house. File:Windcatcher at Ganjali Khan Complex, Kerman.jpg, Windcatcher of
Ganjali Khan Complex The Ganjali Khan Complex ( fa, مجموعه گنجعلیخان - ''Majmou-e-yeh Ganjali Khan'') is a Safavid-era building complex, located in the old center of city of Kerman, Iran. The complex is composed of a school, a square, a caravanserai ...
, in
Kerman Kerman ( fa, كرمان, Kermân ; also romanized as Kermun and Karmana), known in ancient times as the satrapy of Carmania, is the capital city of Kerman Province, Iran. At the 2011 census, its population was 821,394, in 221,389 households, ma ...
,
Iran Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmeni ...
File:Badgir-golestan-palace-tehr.jpg, Golestan Palace, in
Tehran Tehran (; fa, تهران ) is the largest city in Tehran Province and the capital of Iran. With a population of around 9 million in the city and around 16 million in the larger metropolitan area of Greater Tehran, Tehran is the most popul ...
, Iran File:Aghazade mansion.jpg, Aghazadeh Mansion has an elaborate 18-m windtower with two levels of openings, plus some smaller windtowers File:نمای زیرین بادگیر.JPG, A windtower from below, inside, showing that it is partly closed-off.


Australia

Council House 2 in
Melbourne Melbourne ( ; Boonwurrung/ Woiwurrung: ''Narrm'' or ''Naarm'') is the capital and most populous city of the Australian state of Victoria, and the second-most populous city in both Australia and Oceania. Its name generally refers to a metro ...
, Australia, has 3-story-tall "shower towers", made of cloth kept wet by a showerhead trickling at the top of each one. Evaporative cooling chills the air, which then descends into the building.


Europe

The Saint-Étienne Métropole's Zénith is a multi-purpose hall built in
Auvergne-Rhône-Alpes Auvergne-Rhône-Alpes (ARA; ; frp, Ôvèrgne-Rôno-Ârpes; oc, Auvèrnhe Ròse Aups; it, Alvernia-Rodano-Alpi) is a region in southeast-central France created by the 2014 territorial reform of French regions; it resulted from the merger of Au ...
(inland southern France). It incorporates a very large aluminium windcatcher, which is much lighter than the equivalent masonry windcatcher would be. The size of the windcatcher allows it to work in any wind direction; the
cross-sectional area In geometry and science, a cross section is the non-empty intersection of a solid body in three-dimensional space with a plane, or the analog in higher-dimensional spaces. Cutting an object into slices creates many parallel cross-sections. The ...
perpendicular to the wind flow remains large. The
Bluewater Shopping Centre Bluewater Shopping Centre (commonly referred to as Bluewater) is an out-of-town shopping centre in Stone (postally Greenhithe), Kent, England, outside the M25 motorway, east south east of London's centre. Opened on 16 March 1999 in a former cha ...
in the UK uses windcatcher towers. The Queen's Building of
DeMontfort University De Montfort University Leicester (DMU) is a public university in the city of Leicester, England. It was established in accordance with the Further and Higher Education Act in 1992 as a degree awarding body. The name De Montfort University was tak ...
uses stack-effect towers to ventilate.


Americas

A windcatcher has been used in the visitor center at Zion National Park,
Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to its ...
, where it functions without the addition of mechanical devices in order to regulate temperature.


See also

*
Passive cooling Passive cooling is a building design approach that focuses on heat gain control and heat dissipation in a building in order to improve the indoor thermal comfort with low or no energy consumption. This approach works either by preventing heat from ...
*
Qanat A qanat or kārīz is a system for transporting water from an aquifer or water well to the surface, through an underground aqueduct; the system originated approximately 3,000 BC in what is now Iran. The function is essentially the same across ...
*
Solar updraft tower The solar updraft tower (SUT) is a design concept for a renewable-energy power plant for generating electricity from low temperature solar heat. Sunshine heats the air beneath a very wide greenhouse-like roofed collector structure surrounding ...
*
Vernacular architecture Vernacular architecture is building done outside any academic tradition, and without professional guidance. This category encompasses a wide range and variety of building types, with differing methods of construction, from around the world, bo ...
* Yakhchal


Notes


References


External links

* G.R Dehghan Kamaragi (January 2016).
Badgirs, Persian Gulf
. * * * ''(free fulltext)'' * * {{HVAC Cooling technology Architecture in Iran Iranian inventions Islamic architectural elements Islamic architecture Low-energy building Architectural elements Appropriate technology Heating, ventilation, and air conditioning Sustainable building Architecture in the United Arab Emirates Passive cooling Passive ventilation