Windcatcher - Revision history

Designing Buildings at 08:31, 5 July 2021

2021-07-05T08:31:42Z

← Older revision		Revision as of 08:31, 5 July 2021
Line 87:		Line 87:
	* Stack effect.		* Stack effect.
	* Thermal comfort.		* Thermal comfort.
		+	* Types of ventilation.
	* Ventilation.		* Ventilation.
	* Wind energy.		* Wind energy.

Designing Buildings at 10:32, 15 October 2020

2020-10-15T10:32:03Z

← Older revision		Revision as of 10:32, 15 October 2020
Line 92:		Line 92:
	* Wind turbine.		* Wind turbine.

−	[[Category:History]] [[Category:Health_and_safety_/_CDM]] [[Category:Sustainability]] [[Category:Products_/_components~~]] [[Category:DCN_Product_Knowledge~~]]	+	[[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:DCN_Product_Knowledge]] [[Category:History]] [[Category:Health_and_safety_/_CDM]] [[Category:Sustainability]] [[Category:Products_/_components]]

Editor at 19:08, 20 January 2020

2020-01-20T19:08:53Z

← Older revision		Revision as of 19:08, 20 January 2020
Line 78:		Line 78:
	* In regions with very low wind speed they have limited application.		* In regions with very low wind speed they have limited application.

−	~~= Find out more =~~	+	= Related articles on Designing Buildings Wiki =
−		+
−	=== Related articles on Designing Buildings Wiki ===	+

	* Cross ventilation.		* Cross ventilation.
Line 91:		Line 89:
	* Ventilation.		* Ventilation.
	* Wind energy.		* Wind energy.
		+	* Windmill.
	* Wind turbine.		* Wind turbine.

−	[[Category:History]] [[Category:Health_and_safety_/_CDM]] [[Category:Sustainability]] [[Category:Products_/_components]]	+	[[Category:History]] [[Category:Health_and_safety_/_CDM]] [[Category:Sustainability]] [[Category:Products_/_components]] [[Category:DCN_Product_Knowledge]]

Designing Buildings at 16:22, 30 August 2017

2017-08-30T16:22:36Z

← Older revision		Revision as of 16:22, 30 August 2017
Line 1:		Line 1:
−	[[File:Windcatcher.jpg]]	+	[[File:Windcatcher.jpg\|link=File:Windcatcher.jpg]]

	= Introduction =		= Introduction =

−	A windcatcher, also known as a windtower, is an architectural ~~design~~ element ~~that is~~ used for ~~the purposes of~~ natural ventilation. Windcatchers are traditional in Persian architecture, as well as Ancient Egypt, and can be found across the Middle East.	+	A windcatcher, also known as a windtower, is an architectural element used for natural ventilation. Windcatchers are traditional in Persian architecture, as well as in Ancient Egypt, and can be found across the Middle East.

−	They take the form of small towers installed on top of buildings, although they can be found in several different shapes and structures. The towers ~~lead~~ air from outside into a building, ~~thereby serving as a~~ natural ventilation ~~system~~ in hot, arid and humid areas. Windcatchers were typically built facing away from the wind to try and prevent ingress of blown dust and sand.	+	They generally take the form of small towers installed on top of buildings, although they can be found in several different shapes and structures. The towers draw air from outside into a building, providing natural ventilation in hot, arid and humid areas. Windcatchers were typically built facing away from the wind to try and prevent ingress of blown dust and sand.

−	~~The main benefit of using windcatchers, aside from enhancing thermal comfort, is that they~~ are passive systems that require no energy for operation~~, as well as helping to reduce energy consumption and pollution levels~~.	+	Windcatchers are passive systems that require no energy for operation.

	= Design =		= Design =
Line 19:		Line 19:
	=== Bi-directional ===		=== Bi-directional ===

−	These windcatchers tend to be more efficient for airflow circulation and have better performance. They serve two functions – to blow and suck ~~airflow~~ into a building.	+	These windcatchers tend to be more efficient for airflow circulation and have better performance. They serve two functions – to blow and suck air into a building.

	=== Multi-directional ===		=== Multi-directional ===
Line 31:		Line 31:
	The dimensions of a windcatcher depend on the following:		The dimensions of a windcatcher depend on the following:

−	* The ~~mass~~ flow rate required for thermal comfort ~~levels~~.	+	* The flow rate required for thermal comfort.
	* Building dimensions.		* Building dimensions.
	* Materials used in the building (a windcatcher will tend to be built from the same material as the building on which it will be installed).		* Materials used in the building (a windcatcher will tend to be built from the same material as the building on which it will be installed).
−	* The region’s typical wind ~~rate and~~ weather conditions.	+	* The region’s typical wind weather conditions.
	* Building security.		* Building security.

Line 42:		Line 42:

	* Head: Includes a moving column opened and closed either manually or electronically. This helps prevent rainwater ingress.		* Head: Includes a moving column opened and closed either manually or electronically. This helps prevent rainwater ingress.
−	* Column: Fixed in place and can be installed on a rooftop (flat ~~and~~ inclined) using bolts.	+	* Column: Fixed in place and can be installed on a rooftop (flat or inclined) using bolts.
	* Windows: Installed at the lower end of the column to control airflow.		* Windows: Installed at the lower end of the column to control airflow.
−	* Wind vane: Can be installed ~~so as~~ to detect the wind direction.	+	* Wind vane: Can be installed to detect the wind direction.

	= Functions =		= Functions =

−	Windcatchers can function in different ways~~, as follows:~~	+	Windcatchers can function in a number of different ways.

	=== Downward airflow ===		=== Downward airflow ===

−	When using a windcatcher to try and cool the inside of a building, a tall, capped tower with uni-directional opening ~~is often used in combination with courtyards and domes~~. This ‘catches’ wind on one side and brings it down into the building via the tower. While the air is not cooled by the windcatcher itself, the rate of airflow provides a cooling effect.	+	When using a windcatcher to try and cool the inside of a building, a tall, capped tower with a uni-directional opening. This ‘catches’ wind on one side and brings it down into the building via the tower. While the air is not cooled by the windcatcher itself, the rate of airflow provides a cooling effect.

	=== Upward airflow using wind ===		=== Upward airflow using wind ===

−	Windcatchers can ~~often~~ be used in combination with an underground canal, known as a qanat. The tower’s open side faces away from the prevailing wind, and when hot air is drawn down the tower into the qanat it is cooled by coming into contact with the earth and cold water. The building is cooled by this air that is then drawn back up through the windcatcher.	+	Windcatchers can may be used in combination with an underground canal, known as a qanat. The tower’s open side faces away from the prevailing wind, and when hot air is drawn down the tower into the qanat it is cooled by coming into contact with the earth and cold water. The building is cooled by this air that is then drawn back up through the windcatcher.

−	=== Upward airflow ~~using solar~~ ===	+	=== Upward airflow ===

−	In environments that experience minimal wind, or where a qanat is impractical, a windcatcher can be used to function as a solar chimney~~. It~~ allows hot air to travel upwards and escape from the top ~~by creating a pressure gradient. The diurnal cycle assists by trapping~~ the ~~cool air below~~. In this way, large buildings – especially those constructed with thick adobe to provide good heat transmission resistance – can be kept at chilled temperatures during hot periods.	+	In environments that experience minimal wind, or where a qanat is impractical, a windcatcher can be used to function as a solar chimney which allows hot air to travel upwards and escape from the top of the building. In this way, large buildings – especially those constructed with thick adobe to provide good heat transmission resistance – can be kept at chilled temperatures during hot periods.
−		+
−	~~These traditional techniques have now been adapted as the basis for some modern technological cooling solutions.~~	+
−		+
−	~~There have also been modern developments in windcatcher design which have aimed to expand and enhance their operation and efficiency. For example, Bahadori introduced two new windcatcher designs:~~	+

	=== Windcatcher with wetted columns ===		=== Windcatcher with wetted columns ===

−	Water is sprayed uniformly on the surface of a column which is constructed of unglazed ceramic conduits stacked ~~lengthwise~~ on top of one another. By doing so, the column is dampened, and ~~excess water collected and reused via a sump and pump system. The concept is that~~ the evaporative cooling ~~potential can be utilised to deliver much more~~ cooler air to the inside of a building.	+	Water is sprayed uniformly on the surface of a column which is constructed of materials such as unglazed ceramic conduits stacked on top of one another. By doing so, the column is dampened, and the effect of evaporative cooling delivers cooler air to the inside of a building.

	=== Windcatcher with wetted surfaces ===		=== Windcatcher with wetted surfaces ===

−	This is proposed for use in areas of typically low wind speeds. It works by using pads made of a series of straws or cellulose placed at the apertures on top of the windcatcher. Water is continually sprayed on them, meaning that the air that flows through is evaporatively cooled. Due to its subsequent density increase, a downward circulation of air is achieved.	+	This is proposed for use in areas of typically low wind speeds. It works by using pads made from a series of straws or cellulose placed at the apertures on top of the windcatcher. Water is continually sprayed onto them, meaning that the air that flows through is evaporatively cooled. Due to its subsequent density increase, a downward circulation of air is achieved.

	= Limitations =		= Limitations =

−	Some of the limitations of conventional and traditional windcatchers ~~are as follows~~:	+	Some of the limitations of conventional and traditional windcatchers include:

	* They can allow the ingress of small animals, birds or insects.		* They can allow the ingress of small animals, birds or insects.
−	* The head of windcatchers is fixed and doesn’t rotate ~~according to the maximum ambient~~ air direction.	+	* The head of windcatchers is fixed and doesn’t rotate with air flow direction.
	* In regions with very low wind speed they have limited application.		* In regions with very low wind speed they have limited application.

Editor: Created page with "File:Windcatcher.jpg = Introduction = A windcatcher, also known as a windtower, is an architectural design element that is used for the purposes of natural ventilation. Win..."

2017-08-30T12:21:14Z

Created page with "File:Windcatcher.jpg = Introduction = A windcatcher, also known as a windtower, is an architectural design element that is used for the purposes of natural ventilation. Win..."

New page

[[File:Windcatcher.jpg]]

= Introduction =

A windcatcher, also known as a windtower, is an architectural design element that is used for the purposes of natural ventilation. Windcatchers are traditional in Persian architecture, as well as Ancient Egypt, and can be found across the Middle East.

They take the form of small towers installed on top of buildings, although they can be found in several different shapes and structures. The towers lead air from outside into a building, thereby serving as a natural ventilation system in hot, arid and humid areas. Windcatchers were typically built facing away from the wind to try and prevent ingress of blown dust and sand.

The main benefit of using windcatchers, aside from enhancing thermal comfort, is that they are passive systems that require no energy for operation, as well as helping to reduce energy consumption and pollution levels.

= Design =

The direction of airflow at that specific location will determine the windcatcher design. Windcatchers can be one of the following:

=== Uni-directional ===

If wind tends to blow from one side only, then it will be built with one downwind opening, without openings in any other directions.

=== Bi-directional ===

These windcatchers tend to be more efficient for airflow circulation and have better performance. They serve two functions – to blow and suck airflow into a building.

=== Multi-directional ===

These tend to be either four, six or eight-sided windcatchers, and are bigger and taller than the two types above. The exact height and structure of each opening depends upon the specific region’s climate.

=== Cylindrical ===

This is the most technical form of windcatcher and achieves better performance than the other types.

The dimensions of a windcatcher depend on the following:

* The mass flow rate required for thermal comfort levels.
* Building dimensions.
* Materials used in the building (a windcatcher will tend to be built from the same material as the building on which it will be installed).
* The region’s typical wind rate and weather conditions.
* Building security.

= Components =

The following components comprise a typical windcatcher:

* Head: Includes a moving column opened and closed either manually or electronically. This helps prevent rainwater ingress.
* Column: Fixed in place and can be installed on a rooftop (flat and inclined) using bolts.
* Windows: Installed at the lower end of the column to control airflow.
* Wind vane: Can be installed so as to detect the wind direction.

= Functions =

Windcatchers can function in different ways, as follows:

=== Downward airflow ===

When using a windcatcher to try and cool the inside of a building, a tall, capped tower with uni-directional opening is often used in combination with courtyards and domes. This ‘catches’ wind on one side and brings it down into the building via the tower. While the air is not cooled by the windcatcher itself, the rate of airflow provides a cooling effect.

=== Upward airflow using wind ===

Windcatchers can often be used in combination with an underground canal, known as a qanat. The tower’s open side faces away from the prevailing wind, and when hot air is drawn down the tower into the qanat it is cooled by coming into contact with the earth and cold water. The building is cooled by this air that is then drawn back up through the windcatcher.

=== Upward airflow using solar ===

In environments that experience minimal wind, or where a qanat is impractical, a windcatcher can be used to function as a solar chimney. It allows hot air to travel upwards and escape from the top by creating a pressure gradient. The diurnal cycle assists by trapping the cool air below. In this way, large buildings – especially those constructed with thick adobe to provide good heat transmission resistance – can be kept at chilled temperatures during hot periods.

These traditional techniques have now been adapted as the basis for some modern technological cooling solutions.

There have also been modern developments in windcatcher design which have aimed to expand and enhance their operation and efficiency. For example, Bahadori introduced two new windcatcher designs:

=== Windcatcher with wetted columns ===

Water is sprayed uniformly on the surface of a column which is constructed of unglazed ceramic conduits stacked lengthwise on top of one another. By doing so, the column is dampened, and excess water collected and reused via a sump and pump system. The concept is that the evaporative cooling potential can be utilised to deliver much more cooler air to the inside of a building.

=== Windcatcher with wetted surfaces ===

This is proposed for use in areas of typically low wind speeds. It works by using pads made of a series of straws or cellulose placed at the apertures on top of the windcatcher. Water is continually sprayed on them, meaning that the air that flows through is evaporatively cooled. Due to its subsequent density increase, a downward circulation of air is achieved.

= Limitations =

Some of the limitations of conventional and traditional windcatchers are as follows:

* They can allow the ingress of small animals, birds or insects.
* The head of windcatchers is fixed and doesn’t rotate according to the maximum ambient air direction.
* In regions with very low wind speed they have limited application.

= Find out more =

=== Related articles on Designing Buildings Wiki ===

* Cross ventilation.
* Humidity.
* Natural ventilation.
* Passive building design.
* Solar chimney.
* Stack effect.
* Thermal comfort.
* Ventilation.
* Wind energy.
* Wind turbine.

[[Category:History]] [[Category:Health_and_safety_/_CDM]] [[Category:Sustainability]] [[Category:Products_/_components]]