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Passive solar design results in sustainable building

by Zuerita
Passive solar design results in sustainable building

We’ve all experienced it – some houses are always cold, some are too hot and some are just right. How can you ensure that the house you build or buy is going to be cost-effective when it comes to electricity use?

Sustainable buildings save money, reduce your carbon footprint and provide a healthy living environment, transforming buildings from consumers of energy to producers. The design and construction materials you choose to build your house can harness solar energy, without any capital-intensive technology or ongoing maintenance costs. Passive solar design is the starting point of sustainable building.

 

Passive solar heating requires careful application of the following passive design principles:
1. High-density, high thermal mass construction materials that store heat.
2. Northerly orientation of daytime living areas.
3. Passive shading of glass in the summer and selection of appropriate glazing.
4. Insulation and sealing.

This maximises winter heat gain, minimises winter heat loss and concentrates heating where it is most needed. Good passive design helps to keep houses cooler in the summer, reducing the need for air-conditioning.

Due to the high thermal mass of clay brick, the heat transfer delay for an insulated cavity wall is up to eight hours which coincides with nightfall. Therefore the house remains cool during the day, and then stays warmer at night. Photographs courtesy of Brett Boardman

How does thermal mass affect internal temperatures?

Thermal mass is the ability of a material to absorb and store heat energy, and is particularly practical in regions that experience big differences between day and night outdoor temperatures.

Sustainable construction materials with a high thermal mass will slowly capture some of the sun’s energy during the day, but it takes many hours for that heat to pass through the dense material. Due to the high thermal mass of clay brick, the heat transfer delay for an insulated cavity wall is up to eight hours which coincides with nightfall. Therefore the house remains cool during the day, and then stays warmer at night.

The appropriate use of thermal mass throughout your house will improve your comfort while cutting heating and cooling bills. The poor use of thermal mass can exacerbate the worst extremes of the climate, turning a house into a hotbox during the day, or quickly losing all the heat you produce on a winter night – never an ideal scenario.

Following these techniques are imperative when you are looking to save costs with regards to electricity usage, especially at a time when prices are on the increase. Finding innovative ways of correctly utilising the distribution of heat and managing the cold has numerous benefits and should be a top priority for organisations and individuals alike as sustainability is key going forward.

The Clay Brick Association of South Africa
Tel: 011 805 4206
Email: admin@claybrick.org.za
Website: www.claybrick.org

Main image:

Good passive design helps to keep houses cooler in the summer, reducing the need for air-conditioning.

Photographs courtesy of Brett Boardman

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