Wind Catcher

What is wind catcher ?
Natural ventilation had a vital effect on traditional buildings ventilation and wind catcher had a significant place between ventilation items. In hot - arid climates night air cycle , reduced material mass temperature which covered cooling energy demand of building in company on evaporative cooled air in day long. This item placed in Iranian architecture since ancient time. it designed base on wind direction and urban hight texture.



How wind catcher Work?
Wind catcher faced to the good wind direction. When wind entered to it from top open area it redirect with interior slots which force wind to descend into lower levels and enter interior spaces from floor vents. Warm and dirty air had been pulled out of internal spaces from roof vents and fresh airs replaced with them from windows and doors. basically wind catcher work with interaction between wind force and pulling reflection to ventilate and replace air among the building.
It also direct wind to important rooms , basement and water storage space which provide cool and fresh air for building. its essential to mention that some of wind catchers works by convectional cooling rules while other one work on evaporation system. Its must be considered that arid climates of Iran have low humidity so water evaporate fast so base on evaporation physics it reduce air temperature, even more it vaporize interior micro climate that make appealing atmosphere for occupants.
There are deferent shapes of wind catchers that can be sorted in four major groups:
1- Octagonal and tetragonal wind catchers : these types build in areas with different good wind direction which provide maximum performance in ventilation based on wind directions.
2- Rectangular shape : This wind catcher had been made in places with one useful wind direction with two open sides for  ventilation.
3- One open side design : This style made in spaces with dust in the air and it only catch cold air from mountain sides and lead them into the building .
4- Pipe shape Wind catcher : this wind catcher used in hot humid areas and entrance vents faced to the see and absorbed sea to shore wind then move it to interior area.

** Wind catchers are passive systems that worked with air movement, how ever they worked with sun heat. when sun heat wind catcher materials it increase air temperature then hot air ascend and cold air replaced with that (Chimney effect) how ever its not as effective as normal functional system but its helpful.

** Wind catcher hight relate to their surrounding area . For examples cities that surrounded by desert have low rise wind catcher and cities like Yazd which surrounded by mountains make it high rised.

How wind catcher performance had been improved ?
1- Pass air flow over a pool then direct them to rooms (evaporation)
2-Place air channel in depth and under flower bed then watering flowers which cause water penetrate into channel and reduce air temperature by evaporation
3-Place Dried plants in the wind catcher entrance vent and moist them (evaporation)
4- Placing a pool in wind catcher room

P.S. wind catcher room is an space that wind catcher directed to that and other rooms have connection with that space.

References :
1-Bahadori M.N. (1985) An improve to wind tower for natural ventilation and passive cooling, Solar energy Vol 35
2-Bahadori m. (1978) Passive Cooling system in Iranian architecture, Scientific american , Vol 238, No. 2, p.p. 144-154
3- Bahadornezhad Mahdi (2006) Self sustaining cooling systems in Iranian Traditional architecture (in Farsi) , Ashnaei ba danesh Publication, Tehran, P.P. 362-367
4-Eiraji Javad , Akbari namdar Shabnam (2011) Sustainable system in Iranian Traditional Architecture , Procedia engineering 21, p.p. 553-559
5- Ghobadian Vahid (2010) Iranian Traditional buildings review with approach of climatic study (In Farsi ) , Tehran University Publication , Various pages
6-Ghobadian Vahid , Feiz Mahdavi Mahmoud (2011) Climatic Design (In Farsi) , Tehran University Publication, Pages : 94, 112, 142
7- Tavassoli M. (1982) Urban structure and architecture in Hot-arid zone of Iran, Tehran , Roshdie Publication , Fourth Printing
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