Passive Design Features For Buildings

Passive design features, if well designed reduces heat and cooling loads through energy-efficiency strategies in buildings. Elements to be considered in a building with efficient passive design features include, window placement for cross ventilation, air circulation, orientation of the building, the specific glazing type, thermal insulation, shading and materials to minimize energy use.

Orientation of Building

The most effective designs are based on specific understanding of a building site’s wind patterns. A primary strategy for cooling buildings in hot humid climates especially like India is to employ natural ventilation with the orientation of openings and windows in buildings in the correct direction. For tropical countries like India, for e.g. buildings should have maximum openings in the northern direction. Prevailing breezes are from the north and openings on this side make it convenient for natural breeze to flow in. The building design should enable night time temperatures to cool the building to increase comfort for its occupants.

Cross Ventilation



Windows and openings transmit not only sunlight but also both indoor heat and solar heat. That's why they may account for major heat losses in winter as well as major solar heat gains in summer.

Passive cooling by way of cross ventilation maximizes the efficiency of the building envelope by minimizing heat gain from the external environment and facilitating heat loss by efficient movement of air. Natural ventilation can also be increased by reducing barriers to air paths through the building.

Shading



Shading is a strategy to achieve thermal comfort. Shading enables blocking of maximum solar radiation while still permitting day light and prevailing winds.

In climates where winter heating is required, shading devices should exclude summer sun but allow full winter sun to penetrate. In climates where summer is harsh, shadings should protect the building from heat gain.

It must be kept in mind that shading requirements vary according to climate and building orientation. Windows and openings would require different shading options. During the spring, fall, and cooling season, the windows should be shaded to avoid overheating, and heat gain within. While in winter the shading should enable maximum sunlight to enter.

Unprotected glass is a great source of heat gain. Therefore it is essential to shade it. Shading of glass is a critical consideration in passive design. Windows and glazing are a very important component of passive design because heat loss and gain in a well insulated home occurs mostly through the windows.

While choosing the right energy efficient glazing solution, the façade design needs to incorporate an understanding of the orientation of the building, location, wind and solar actions with respect to the building.

Façade designing to improve passive design features is generally practiced throughout the world and has shown to produce buildings with low energy costs, reduced maintenance, and superior comfort. Passive design features, if well designed reduces heat and cooling loads through energy-efficiency strategies within interiors.