Question

explain the working principles of natural ventilation and explain passive design approaches suitable for cold climate

Answer 1

Working principle of natural ventilator :

SUPPLY OF OUTSIDE AIR INTO A BUILDING THROUGH WINDOWS OR OTHER OPENINGS,DUE TO WIND OUTSIDE AND CONVECTIONEFFECTS ARISING FROM TEMPERATURE OR VAPOUR PRESSURE DIFFERENCES BETWEEN INSIDE AND OUTSIDE OF THE BUILDING.

The driving forces in natural ventilation are thermal buoyancy and wind pressure on buildings. The design of the building, the form of window openings and location have a significant impact on the quality of the indoor climate.

Passive design approach for cold climate  :

Regions that's fall under the cold climate experience very cold winters as they are at a very high altitude. The temperature ranges between 20-30°C in summers, while in winter it can range from -3°C to 8°C making it quite chilly. As such, trapping the sun's heat whenever possible is a major design concern. At the same time, the buildings in such regions need to be properly insulated so that the internal heat is retarded with minimum loss to the environment. Expose to cold wind should also be minimized.

The main objectives of the building design in these zones are:

1. Resisting heat loss:

• Decrease the exposed  surface area of the building
• Using materials that heat up fast but release heat slowly.
• Providing buffer space between the living area and the outside.
• Decreasing the rate of ventilation inside the building.

2. Promoting heat again :

• Avoiding excessive shading
• Utilising the heat from appliances
• Trapping the heat of sun.

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