Friday, June 13, 2008

Energy-efficient passive solar design - a visit to Naripinda

This article, which I wrote after an interview with Phil P and Jan P at their inspiring energy-efficient solar passive house in May 2008, was first published in the Palerang and District Bulletin in June 2008. The photo on this website (showing part of the house and the vegetable patch near the kitchen) was taken by me and is different to those published in the Bulletin version.

It took two years of planning and many long hours of discussions before Phil P and Jan P decided on the final design of their award-winning solar passive house in Bywong. Located on a small rural-residential holding, Naripinda (the word means galah in the now extinct Nhirrpi language of South Australia) combines all features of solar passive building design.

Both owners are passionate about reducing their environmental footprint through good planning and sensible use of their building. As Jan P explained, rather than spending money on elaborate fittings or unnecessary décor, they focussed on getting the solar basics right – good orientation, double-glazed windows throughout the house, dark floor tiles and thermal mass inside the building.

Instead of a standard house design with rooms on all sides, this house only has single-room depth with north and north-easterly orientation for all rooms. A double row of windows on the higher northern walls maximises sunlight exposure. Smaller windows in the lower walls on the southern side allow views of the courtyard and the surrounding bush. The eaves are specifically designed to cut out excessive heat in summer while allowing the winter sun into the house to warm up the rooms on cold days. All western walls are without windows and have extra insulation to protect from the intense afternoon sun.

Jan P said that in preparation for their building project, she and Phil did a lot of research into solar passive design features but they had no pre-conceived ideas of what the house should actually look like. This open-minded approach resulted in a strikingly unusual building. Rather than constructing an elongated row of single rooms to achieve optimal solar exposure, the owners decided to go for a more interesting design whereby the house is “cut into two halves” which sit at a slight angle towards each other on different levels on a slope.

The silver-coloured corrugated tin exterior with its large window fronts and the split design give the place a feel of lightness which defies the fact that this house incorporates a significant thermal mass. Phil P explained that the interior trombe wall, which connects the two sections of the house, used up as many bricks as one would find in an average brick veneer home. In addition, all outside walls are made from ‘reverse brick veneer’ where the brick is on the inside of the building rather than the outside. Brick is a good heat store and helps to retain heat inside the building on cool evenings and in winter, while the light coloured exterior walls reflect intense summer heat away from the house.

To answer my question of what advice he would give to prospective home builders, Phil P took me outside. “You need to look at the landscape,” he said. “We were first advised to build on top of the hill to get a good view. That would have meant destroying the beauty of the environment by running heavy machinery across to get to the top. It also would have meant exposure to wind, heat and a heightened fire risk. Where we are now (on a plateau lower down surrounded by gentle slopes on three sides), we are well protected. Walk around your property, get to know your place well, and then make decisions. Everybody will have an opinion, so you need to watch out. If something sounds like bad advice, it probably is.”

3 comments:

  1. I want to make calculations of heat energy efficient house for cold countries such as Russia, Alaska of USA and Canada. This house use energy of wind and heat energy of soil.

    I am finding investor for this works. The investor will be used technologies that will be developed.

    See details here:
    http://simulations.narod.ru/energy_efficient_house/

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  2. Very interesting article. No one ever builds their own house here, so different from Australia.

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  3. This is really interesting. I have wondered about 'how' to make a energy efficient house. I love their consideration about the local environment too. So often it is about the view, but how much time do we actually spend looking at the view, when we are 'living' in tour house. I like your writing by the way...can you 'sell' to some one else once published, I am sure there would be a buyer!! Love Jxx

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