WIND CATCHERS

INTRODUCTION

Air movement is a major factor influencing indoor climate and should be considered when planning and constructing buildings. For the purpose of climatic design, only regular winds are relevant. Regular winds can be utilized for cooling. If the temperature of the circulating air is below the indoor temperature, then the cooling effect is obvious.

Wind catchers

Wind catchers are a significant feature in the

traditional structures to ventilate and cool

buildings in hot desert and hot, coastal

regions. Wind pressure forces air down the

wind catcher. Air circulation inside the

building is achieved if there are openings on

the opposite side allowing suction of inner air

by lower pressure.

Roof wind catcher

Also called wind chimney is built onto the

roof. In some places the catchers are

unidirectional and orientated to catch

favourable winds or are facing away from it to

draw cool air from the court yard through

rooms, and expel stale air and smoke. By

change of wind they are anticipated to reverse

their function.

Unidirectional roof wind catcher

Solar chimneys and induction vents

Solar chimneys make use of solar heat to

reinforce natural air convection. A black

coated metal pipe chimney is heated by the

suns radiation and so is the air inside. The

latter then rises taking the interior air up and

out. This system is self-regulating, the hotter

the day, the faster the air motion

SOLAR CHIMNEY

Black coated pipe as solar chimney

Principle of thermic effect

Glazed solar chimney

Principle of thermic effect

A variation of solar chimney with solar air ramp

WIND TOWERS

For architects, the wind is an important factor in the design of a building

Wind's effect on the thermal comfort through convection or ventilation and the penetration of air in interior spaces.

Wind towers as their name implies, are ventilation tools used for obtaining natural cooling.

ORIENTATION & FUNCTION OF WIND TOWER AT YAZD, IRAN

4 DIRECTIONAL WIND TOWERS

WIND CATCHERS(Traditional & Contemporary)

Wind catchers at Yazd.

8 DIRECTIONAL WIND TOWER

WIND CATCHERS WITH EQUAL CANALS

WIND CATCHERS WITH DIFFERENT CANALS

MATERIAL, COLOUR & TEXTURE

Multi-directional roof wind catcher(tower)

Multidirectional wind towers utilize winds from any

direction. Generally, wind towers are square in plan

and have four internal shafts.

The principle involved is to catch an unobstructed breeze at a high level and channel it to areas in the bottom parts of the building. The increased air-velocity supports perspiration and is thus cooling. The ducts are preferably built in a massive way to absorb the heat of the incoming air and not exposed to solar radiation (e.g. northern wall), to enhance efficiency.

Multi-directional roof wind catcher(tower)

plan, section and perspective view

A recessed, horizontal niche on the external wall, e.g. on the floor level and in the roof parapet, creates a slot between two vertical, structural posts. These mid-wall or parapet wind intakes or series of them may allow for enough cross-ventilation through the internal spaces in humid weather, while preserving visual privacy.

Mid-wall and parapet wind catchers

Mid-wall and parapet wind catchers

Wind towers in UK

The simplest design for a wind tower is a vertical construct that projects above its surroundings and has an open top. This will ensure negative pressure and provide suction in all wind directions. If the ingress of rain is a problem, a cover can be placed above the top.

Wind towers at Ionica, Cambridge, UK

Wind towers and wind scoops

Wind scoops can be used in combination with wind towers to create a system by which cool air is provided by wind scoops and warm air is then extracted via wind towers.

Natural ventilation by means of a combination of wind towers and wind scoops can either be via two separate devices, or a single device with both inlet and extract.

Again, the wind scoop should be omnidirectional, and if a combined device is used, a omnidirectional wind tower can also be employed.

Wind scoops at Bluewater Shopping Centre, Kent, UK

Monodraught wind catcher

FUTURE OF TRADITION

Shower Tower, Australia