Cairns Regional Council
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Sustainable Tropical Building Design
2. ENERGY AND EMISSIONS
Figure 7. Diagram showing clerestory windows and light shelves Adapted from John C. Clem Building a Better, Greener Home http://www.clemdesign.com
North facing celestory windows allow light to enter the building. The awning excludes midday sun, allowing just some Winter sun to enter the building
Clerestory windows
Light tubes
Another important element in natural lighting is the use of clerestory windows. These are high, verticallyplaced windows that are ideally north facing. The benefit of clerestory windows can be enhanced by using light-coloured interior walls to further reflect light into interior areas. Clerestory windows can be a good source of diffuse light, and can also be useful in allowing hot air to leave the building. In the tropics, north facing clerestory windows will work most effectively, as they will exclude summer sun. As with light shelves, awning width should be designed to exclude unwanted sun. East or west facing clerestories are not recommended as they cannot be effectively shaded.
Solar tubes, light tubes or light pipes are used for transporting or distributing natural or artificial light. Installed between the roof and interior ceiling, solar tubes capture daylight, refract and reflect it through a tube, and disperse the light to an interior space using a diffuser. The concept was originally developed by the ancient Egyptians. The exposed portion of the light tube consists of a dome that collects and refracts as much sunlight as possible from as many different directions as possible. The tube itself is lined with a highly reflective material to help light travel through with minimal loss. At the other end of the tube, the light passes through a diffuser that disperses it throughout the interior space.
Light shelves deflect light on to the ceiling, helping to soften and diffuse light