by Alice Ostrowski
During a recent camping expedition, a time of basic, relaxed living, where the day started with sunrise and ended with sunset, I was brought back to the elemental needs of living; comfortable spaces to cook, eat, clean, sleep and relax.
Just like setting up camp, the design of a home should incorporate and engage with all aspects of its site. This is the main principle behind solar passive design. It’s about catering for our instinctive needs of shade, shelter and sun, which since caveman times have not greatly changed. The caveman considered his home a tool, an ephemeral space that grew in response to needs, comfort and daily activities. Today these principles have been largely lost due to mass housing production and insular modern living. Fortunately, an increasing shift in focus has us reconsidering our lifestyle, our energy consumption, and our interaction with the natural environment.
There are many design methods to consider when designing a solar passive home in your local climate, but by no means is it difficult. It is a natural instinctive way of living, achieved through standard environmental design principles.
If you are embarking on renovations or building a new home ask yourself or your designer how solar passive design can be implemented to create your living house. If you are unsure of what this may entail here are a few pointers for you to start the process and discuss with your designer.
From Australia’s tropical north, to the arid desert and down to the temperate south, to live in a solar passive house is to comfortably live with the climatic conditions. It begins with the correct building orientation to collect and store heat from the sun in cooler months, and minimising summer sun while encouraging cooling breezes to purge excess heat at night. The next time you are outdoors, consider the way you shelter from the sun or rain, cool off against an ocean breeze or sunbake when you feel cool; these behaviours also apply indoors.
Like an overheated car on a summer’s day, a poorly designed house will reach extreme temperatures when exposed to the elements. However, by using the building ‘body’ – the careful placement of windows and a balance of thermal mass, insulation, shade structures and breezeways – a space is created that is living and reduces the need for mechanical heating and cooling; the occupant is forced to adapt to the climate and natural rhythms of the day and cycle of the season. 3
Thermal mass like concrete floors, water bodies and rammed earth walls can also be used effectively for cooling and heat absorption when appropriately incorporated. Thermal mass acts like a heat sink, which means it absorbs heat during the day, and at night the heat is released.
8. For natural heating, ideally a rammed earth wall is located internally where it can capture winter sun from clerestory windows. Natural ventilation and access to prevailing breezes will assist with the removal of unwanted heat.
In the hot, humid climate of Australia’s north, where winter heating requirements are minimal, building orientation and design should aim to exclude sun all year round and maximise exposure to cooling breezes. Architectural form can enhance this, like in Coco Eco, where the main living pavilion twists up to the south west as a ‘windscoop’ directing available breezes. 1.
Lightweight construction materials are preferred, with roof and under-floor ventilation, cross-ventilation for breeze flow, light coloured, reflective roof and wall materials for minimum heat absorption, high raked ceilings and most importantly, shade. Well screened and shaded outdoor areas and sleepout spaces allow living versatility.
4. Spaces can become ephemeral with timber screens, bifold doors and clear cladding blurring the distinction between the internal and external spaces.
2. Decks and boardwalks further facilitate this outdoor connection and can adjoin other living pavillions while also preserving the natural environment below.
Shaded thermal mass may also be incorporated to absorb heat and naturally regulate temperature, especially where there may be a large difference between night and day outdoor temperatures.
Moving further south, a hot dry summer and cool winter climate will require a balance of maximising solar access in winter while minimising in summer. Ideally the main living and bedroom spaces capitalise on a north-facing orientation. 6.
Controlling east and west solar access is one of the more difficult design issues, especially when desirable views come in to play. This can be combated with flexible shading methods, which blocks low-angled summer sun in the morning and afternoon, like adjustable, sliding louvred screens, deciduous planting and minimal tinted glazing.
To maximise and control north solar penetration is incredibly simple. Large windows to the north, shaded by the right length and angled pergola, eaves or awnings, can allow sun penetration in winter and shade in summer. 5. Also known as a ‘solar pergola’, correctly angled fixed timber louvres allow winter sun access and summer shade over an external north-facing deck. The natural change in sun angle during the seasons allows this simple design approach.
Just like my wardrobe adapts to changing seasons, I’d like to live in a space that provides me with the versatility of having spaces I can use in winter and summer. Both northern and southern indoor and outdoor living spaces can provide this flexibility. 9. Ideally, living spaces are located on the northern part of the dwelling to maximise light and heat gain with a strong connection to the outdoors. Along the coast of Western Australia, for instance, well shaded southern spaces can capture cooling afternoon breezes for summer relief.
One thing I’ve missed most in some of the houses I’ve lived in is the ability to see, hear and feel what the weather is doing outside from the inside. If I can’t see the sky, claustrophobia sets in. High level double-glazed windows coupled with high ceilings can increase the feeling of space with access to light and views beyond. 10.
Unlike a flat ceiling with a traditional roof pitch, a raked ceiling angled up towards the north can ensure deep solar penetration but also sky views, which may normally be limited on small urban blocks. In addition, the angle of the roof and ceiling allows good cross-ventilation, and, with low and high level operable windows or vents, warm air can be channeled out and cool, fresh air pulled in, creating what is known as a ‘thermal chimney’ effect. 7.
Our time to embrace antipodean climate is well overdue. The style of an Australian living house is unique. It discards styles that are dysfunctional for its local climate, such as the eaves-less ‘European’ houses and suburban ‘McMansions’ where bigger is better.
Alice Ostrowski is an architect working for Paradigm Architects based in Perth who specialises in environmentally sustainable design in urban and regional areas of Western Australia.
The photo above shows a rammed earth central spine wall which captures winter sun from clerestory windows for natural heating. [Frog Choir Residence, Paradigm Architects, WA; Photo: Stephen Blakeney]
* Editor’s note re reference numbers – these refer to specific photos which were used in the print version of this article, March, 2012. You can see them by looking at p.16 of the virtual copy here: http://www.livingnow.com.au/read/read-online.html
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