SUNDAY, FEB 5, 2023: NOTE TO FILE
Module 5-3
Bioclimatic Strategies
Bioclimatic strategies are a key element of designing sustainable houses. The aspect (relative position) of the building to the arc of the sun along with attention to specific site conditions is paramount in order to create an ecologically intelligent design. Where heating is a key issue, a passive solar design will determine the aspect of the building to the sun. Where cooling is an important consideration, landscaping can provide shading and the wind natural ventilation. More specifically; -
- Sensitive site design attempts to minimize environmental disturbance by taking cognizance of; weather influences of sun, wind and rain; niche microclimates; site hydrology, topography and geology; and, site flora and fauna.
- Solar aspect of buildings or passive design is all about building aspect to maximise solar gains as illustrated in the 3 Figures below, whilst fourth Figure shows some solar harvesting designs using thermal mass of masonry and rock beds, as well as, air flow gaps. Active solar heating can be achieved by building thermal mass into the structure. Thermal mass combined with thermal insulation in a building buffers changes in the outside environment, thereby creating more even and comfortable conditions inside the structure. These processes can be enhanced with active systems, using fans and pumps.
Source: https://www.solarmarket.com.au/residential-solar/considerations-before-installing-solar/
Functional Planning for Solar Gain. Source: https://www.researchgate.net/figure/Room-orientation-related-to-the-movement-of-the-sun-throughout-the-day-Northern_fig1_319097274
Design for solar gain
- Green roofs for insulation, cooling and aesthetics can provide extra insulation as well as aesthetics to a design. Many green roofs absorb the sun’s energy as opposed to reflection and can reduce the ambient temperature within an urban district. A good option for green roof plants is sedum or to allow the natural surrounding grasses to establish themselves. However, regular maintenance of the green roof is essential in order to remove any shrubs or tree seedlings which take root. A typical green roof design in Figure below shows the various layers that make up a good design detail which ensures that the roof structure remains waterproof. The green roof design around the verges and gutters is usually quite challenging, but again, the details must ensure that excess rainwater is adequately drained away at all times.
Green roof design detail (Source: http://www.rooftoplandscapes.co.za/green.php)
· Shading with plants is landscaping with deciduous trees and extended roof lines to provide shading for summer cooling, whilst low sun in winter through bare trees can provide passive solar heating. Similarly, pergolas with vines over verandas can provide much needed summer shading whilst in winter the leaves will fall and allow winter sunlight for warmth, as illustrated in the image below.
Shading with plants (Source: https://www.lanser.com.au/2019/02/05/how-to-use-passive-design-to-save-money/)
· Natural ventilation is where it is necessary to have forced air ventilation for bathrooms and kitchens. There are also useful techniques for passive or natural ventilation, for example termite ventilation (see short video), which can be applied depending on the specific site and climate.
An iconic building which applied biomimicry to model termite ventilation is the
Case Study No.1: Biomimicry in ecological building design
Module 5, lesson 4
