Passive solar design has been described as the future of building, but historically it has been a practice from ancient times. In China, Egypt, India and Ancient Greece buildings and homes had characteristics of solar orientation, thermal mass and ventilation with strong cosmological beliefs associating the directions, the elements and ones health as contributing factors.
Passive solar design focuses on renewable energy sources such as the sun and wind to provide a buildings heating, cooling, ventilation and lighting. As that are all directly related to natural energy use, passive solar design is net zero energy as it is free and reduces the need to consume large amounts of energy from other sources that deplete the earths resources. Unlike active solar systems, passive systems do not require mechanical or electrical devices it is all in the design. Simulation tools can help assess the impact of the design to be built, and in an existing building, passive design assessment and infrastructure change can be done through renovations and upgrades.
When the sun hits a building, the materials can transmit, reflect or absorb the solar radiation. Natural air movement can be optimised for cross ventilation and natural cooling. The main principles of passive design to be considered in construction and design are:
- Location – identify the climate and an understanding of the principles of the thermal envelope to create a balance.
- Orientation – the position of the building is key to take advantage of the sun, the direction and types of wind in the area, seasonal variations. Ideally maximum exposure to the sun in winter is optimal, while receiving shade to walls and windows in summer. These factors will also help the running costs of the building.
- Shading – through the use of shutters, pergolas, eaves, awnings and plants, up to 90% of the heat generated from direct sun can be blocked to avoid overheating and through calculations of the sun’s angle as it hits the building one can calculate the winter sun so it is not entirely blocked out when warmth is required.
- Building Layout – all the rooms and outdoor spaces should be laid out to maximise purpose and comfort when in use – aspects to consider are morning light, all day sun, horizontal shading to prevent overheating in summer and solar gain during winter and cool afternoon breezes.
- Natural Ventilation – using the natural force of wind to deliver ventilation and fresh air into buildings. The specific approach and design of size and placement of openings to amplify the natural ventilation systems will vary based on building type and local climate.
- Window Design – windows although they provide light and views can be a major source of unwanted heat gain in summer and heat loss in winter so size, location and glazing systems need to be considered to improve the window’s thermal performance and educe energy costs as well as greenhouse gas emissions.
- Insulation – acts as a barrier to heat flow so the amount and type of insulation the building requires will depend on climatic conditions to keep heat in, keep heat out, control moisture issues and offer soundproofing.
With the goals of energy conservation and minimising impact on the earths resources, passive solar design principles are key at the design phase of any building. Given the expected changes to the climate we are already witnessing, we at Chiodo Corporation aim to use passive solar design at the design concept of all of our projects to work with the earth and the natural energy systems we have.
“Sitting at our back doorsteps, all we need to live a good life lies about us. Sun, wind, people, buildings, stones, sea, birds and plants surround us. Cooperation with all these things brings harmony, opposition to them brings disaster and chaos.” – Bill Mollison
