When working on a site situated in a cold climate, it’s important that the thermal and other environmental comfort is taken care of for the users.
What is passive design?
Passive design makes use of the existing design components to enhance the energy efficiency and sustenance of a space. This is done without making use of any external tools or devices to create high-performance buildings or spaces.
With the right kind and amount of heating, lighting, and ventilation, we can transform a building to have ideal indoor and outdoor comfort for the users.
Passive design strategies for cold climate can be broadly segregated based on the following:
- Building Orientation
- Building Form
- Landscaping and Vegetation
- Thermal strategies
The below-mentioned strategies help in the reduction of energy consumption and increase in the comfort for users living in sites situated in cold climates.
- Orient the building more to the south for maximum winter sun penetration into the building openings.
In cold climates, indoor air is cooled in the process of it flowing from inside to outside. This could lead to excessive water vapour condensation if not considered during the design.
- Air-tight construction will prevent hot air from escaping from the building envelope and cold air from entering it.
- Covered entrances and open spaces prevent excessive cold air from disrupting the comfort of the users while entering or exiting the building.
- Recessed entryways help protect the entrance from prevailing winds.
- Open spaces need to be protected from prevailing cold wind.
- Interior spaces inside the building need to be zoned based on the needs of each space with regards to the solar and ventilation requirements.
- Cross ventilation - Placing windows at multiple facades at the right places to assist the exchange of the existing air with new air.
- Stack ventilation - since the prevailing wind tends to be at a higher pace in cold climatic areas, wind can be used in stack ventilation and also for energy production.
Ex: Chimney effect, wind towers, ventilators, evaporative cooling and so on.
- Airlocks/lobbies - sealing of the doors and openings with airlocks help equalize air pressure between inside and outside.
- Make the most out of the available natural light in the site and design openings to let in maximum light.
- Use of glass facades and roofs for appropriate daylighting for spaces that require the most light.
Cold climates often need highly glazed facades for maximum natural lighting. Right shading systems need to be designed to reduce the cooling demands of a building.
- Installation of automatically controlled shading systems helps the users choose the right amount of shade required at the right time.
Ex: Overhangds, Louvres, Awnings, vegetation and so on.
- Roofs must also be protected from direct solar radiation through coatings, vegetation and so on.
- Double glazing on windows is highly effective for cold climates to efficiently reduce heat loss.
- Provide south-facing glass windows to maximize the heat gain during the winter months when it will be the coldest.
- Window glazing with a low U-factor will help reduce winter heat loss and retain heat from the day for use during the night.
- The glazing should be well insulated to prevent the leakage of heat into the exterior.
- Providing shared walls help reduce heat loss by reducing the number of walls exposed to the exterior environment.
- Facades with high thermal mass are a good option where there are large temperature variations.
- Thicker walls help insulate the space and help retain the heat inside the building.
- Darker coloured exterior walls are preferred to help absorb the maximum amount of heat.
- In spaces where there is a lot of rain or snow, the provision of steep and sloped roofs help prevent water stagnation on the roofs.
- Provide materials and design that allow maximum solar penetration into the building such as glass.
- Insulating materials such as timber and mud plaster can be used on the walls to create facades that prevent heat loss as much as possible.
- Timber panelled walls and windows help reduce the rate of transfer of heat and are also mostly available in cold climatic spaces.
- Use trees as natural wind barriers or buffers by planting them near windows to block cold air from entering the building.
- Plants and trees chosen for landscaping must be able to survive the harsh climatic differences.
Other Thermal Strategies
- Make sure to utilize heat from existing appliances inside the building such as the burner and fireplaces.
- Rock beds help increase the thermal mass of the building by making use of existing heat to create more heat.
- Earth berms - Utilizing earth against building walls to reduce the amount of heat loss from inside the building.
- Sunspaces help store solar heat centrally for equal distribution into all spaces inside the building.
With cold climate passive design, the main focus is to retain heat gain received by the building. That does not take away from the fact that there need to be strategies to help prevent unwanted climatic differences.
Finding the right balance between both the needs of the building is where lies the success of the design.
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