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Passive solar building design
Passive solar building design involves modeling, selection and use of appropriate passive solar technologies to maintain the building environment at a comfortable temperature. This is achieved through the sun's daily and annual cycles. As a result, it minimises the use of active solar, renewable energy and especially fossil fuel technologies.
Passive solar building design is only one part of thermally efficient building design, which in turn is only one part of sustainable design. The terms are often used erroneously as synonyms (passive solar design does not relate to factors such as ventilation, evaporative cooling, or life cycle analysis unless these operate solely by the sun).
Direct gain involves the positioning of windows, skylights and shutters to control the amount of direct solar radiation reaching the interior spaces themselves, and to warm the air and surfaces within the building. The use of sun-facing windows and a high-mass floor is a short-cycle example of this.
Direct solar gain systems suffer because historically there were no reasonably priced transparent thermally insulating materials with R-values comparable to standard wall insulation. This is now changing in Europe, where superinsulated windows have been developed and are widely used to help meet the German Passive House standard.
Indirect gain, in which solar radiation is captured by a part of the building envelope designed with an appropriate thermal mass (such as a water tank or a solid concrete or masonry wall behind glass). The heat is then transmitted indirectly to the building through conduction and convection. Examples of this are Trombe walls, water walls and roof ponds. The Australian deep-cover earthed-roof, innovated by the Baggs family of architects, is an annualized example of this path.
In practice indirect solar gain systems have suffered from being difficult to control, and from the lack of reasonably priced transparant thermally insulating materials.
The images provided are from Powered Living, passive solar architects based in New Zealand.
Passive Solar - What is it?
Passive solar, from a residential housing perspective, is simply a home which maintains a comfortable inside temperature by accepting, storing and preserving the heat from sunlight, by using the building design layout and construction fabric.
Warm in Winter - Cool in Summer
That's how we want our homes to be right? And if it takes a mimimum amount of heating and cooling energy to keep them that way, then everybody wins. Well it can be done inexpensively and passive solar design is the way to do this.
Passive Solar Design
The basic premise of passive solar design is simplythat of good home design - make the most of what's available to you, in terms of both the environment and the materials planned to be used. Let the tendancies of nature work for you, not against you, and work towards the goal of minimizing the reliance on back up energy to heat, cool and operate your home. The design and construction strategies that work best to achieve this result are really a rearrangement of materials and intelligent application of all aspects of design that are used in a coordinated, integrated and comprehensive way.
This approach is far more important than buying special materials or incorporating add on features, and using common sense and sensitivity to the homes specific environment is key in achieving a successful solar result. Unfortunately, this is often not appreciated, understood or applied, and as a result the fundamental ways of building in harmony with the sun, the seasons and the landscape are not being used.