PDC…..Week 9

After a week’s break, we began week 9 with a look at energy-efficient housing. In a temperate climate (e.g. Melbourne), it’s cold in winter and hot in summer, therefore in winter we need to keep the cold out and the warmth in, and in summer we want the heat out and the ability to let the cool evening breezes in.

So, in the southern hemisphere, the house should face north and length should be about one & a half times width. Bedrooms and other little-used rooms are placed on the shade side while high activity areas face the sun. Materials with high thermal mass (slab floors, internal brick walls) store heat through the day and release it in the evening. Windows on the (hot) west side are minimised. Drapes are important; floor-to-ceiling, and with pelmits.

A glasshouse on the sun side can provide winter warmth and a shadehouse at the rear provides cooling breezes to enter in summer.

Insulation is important to keep heat in. Bulky stuff like wool, fibreglass and foam are ideal. Reflective insulation (sisalation) provides a radiant heat barrier and prevents heat radiating down from the roof.

Vegetation can also be used to good effect. Deciduous trees screen out the summer sun and allow the winter sun in.

We looked briefly at house design in the humid tropics and desert (I’m not likely to be shifting to either of those in the near or distant future) before moving on to alternative and appropriate technology, which generally means things that don’t use or need fossil fuels to run them.

Pumps for moving water around are many and varied; diesel, windmill, solar, and here’s a fascinating one—the ram pump. This little beauty can actually use gravity pressure to send water higher than its original source.

Electricity can be generated using micro-hydro, wind or solar. The latter two are expensive and need battery storage for night-time use or when the wind isn’t blowing. Micro-hydro is cost-effective where a constant flow of water is available.

Heating water can be done in a solar heater where water is heated in copper tubing and rises to a collector tank. Evacuated tube heaters are newer and more efficient, but also more expensive.  A wetback stove consists of special piping attached to the back of a wood heater or stove which heats water which can then be stored. A low-tech version is simply to install black tubing on a hot roof.

Cooking. An efficient wood-burning stove is the rocket stove. It burns small kindling and can be maintained on garden prunings. Solar cookers cook slowly, using the sun’s heat, which is reflected onto the cooking pot by a parabolic collector. A box lined with something reflective like aluminium foil does a good job, too. Insulated boxes cook slowly and are great for cooking grains, pulses and stews. Cooking is started on a conventional stove and the pot is placed in the box where the contents simmer slowly.

Preserving is a way of keeping food from glut times through to scarce times. Solar dehydration is the best low-tech option. A solar dryer can be as simple as a piece of flywire on a wooden frame, or as involved as a number of frames in a cabinet with a rising warm air current.

Low-energy refrigeration can be achieved with a cool cupboard. Air is drawn up through an underground pipe and through an insulated cupboard. Food is kept in a series of baskets so that cool air can circulate around the food. Not suitable for meat or dairy, though. The old coolgardie safe does a good job, too.

So, there are lots of ways in which we can still do things when fossil fuels run out. We might not like it, but we’re going to have to get used to living the way people did before the fossil fuel age, with all its associated problems, hit us. I think we just might be the better for it in the long run.

After lunch we spent a couple of hours coming to grips with our final design project. We’ll spend more and more time on it in the final few sessions. Into the home straight now!

4 Responses to “PDC…..Week 9”

  1. simply.belinda Says:

    Good Luck with your final design.

    Kind Regards


  2. rabidlittlehippy Says:

    I have a dehydrator which I love but I’m conscious of the electricity needed to run it. I plan to build a solar one over the winter. I have read about and seen coolgardies and they’re fascinating the way they work. The same concept can be used for cooling bubba in his cot too although it’s not as cold with the top open. 🙂
    We have solar hot water and a wetbacked stove/heater and then backed up by gas boost (the gas isn’t yet connected) and electric boost as a final back up (which we’ve switched off at the meter box) and so far we’ve toasted ourselves every shower. 🙂
    We also have a creek running through our block but it’s only seasonal or it was this year with the ultra dry summer. We’re still considering a water wheel as any electricity harvested sustainably reduces fossil fuel usage. 🙂
    I’m also into water bath bottling and newly into pressure canning. Once we get our heads around our wood heater/stove/oven we can most definitely use the heat from there to put away for another day.


    • foodnstuff Says:

      Google micro-hydro systems for info on in-stream generators.


      • rabidlittlehippy Says:

        I did when the concept came up in a post from (The greening of) Gavin and this is the 1 we found. http://www.platypuspower.com.au/ Sadly our creek, which is in reality called a drain on the municipal map appears to be only seasonal so we will see what kind of water flow we get this winter. IF we get enough a home built generator that we run seasonally might be a reality but we won’t spend the money on a system that can’t be run year round.


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