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Housing - new houses

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Energy-effective houses for cool temperate zones

Derek Wrigley

 

How can we eliminate/reduce greenhouse gas emissions and achieve self-reliant housing?
To understand where we should be going it is important to understand where we are at the moment…..

Most of the current housing designs by developers and others are unsustainable

  • Bad subdivision design prevents effective use of solar gain, leading to increased need for artificial heating and increased CO2 emissions.
  • Small block sizes might reduce housing footprint, but force bad orientation and solar gain, limit home vegetable growing and fruit trees (future essential) and play space which are unhealthy trends.
  • Roof designs have become antithetical to effective solar gain (broken roof areas, small areas, non-rectangular, ineffective orientations).
  • Street/garage/orientation juxtaposition often prevents adequate solar gain.
  • We should not continue down the same path.


What could be done in new housing design :
Start by designing the optimum self-reliant house and then plan the optimum subdivision (rather than the opposite, as now, of trying to fit a solar effective house onto an inadequate block).
Minimise the planning impact of cars having to be garaged at the house (car/street/access relationship is often too demanding and anti solar-effective.
Plan the house to optimise roof solar collection (hot water and electricity), and to collect all rainwater for all domestic uses.
Design to use full house width reflectors to obtain maximum winter solar gain in all southern rooms.
Place large water tank under concrete floor slab to release land area for better purposes, utilising spoil for berms around external walls including cool air intake system.
Design building structure to serve several purposes:
Resist heat gain in summer (roof and walls).
Allow maximum solar heat gain in winter (roof and walls. north and south).
Minimise/eliminate east and west windows.
Optimise internal mass to take advantage of winter solar gain during daytime for release during night.
Eliminate bushfire risk (no flammable materials in roof structure).
Create adequate internal mass to give thermal balance for optimal use of solar gain in winter and coolth in summer.
Achieve summer cooling by use of natural vertical buoyancy forces rather than reliance on artificial air conditioning.
Use this vertical technology to also supply daylight (and sunlight) into dark house areas as required, (cheerfulness – unrecognised factor).
Integrate all solar gain technology as part of the house structure (double function and half the cost with aesthetic advantage and much lower running costs – Factor 5), e.g. Integrated PV panels transfer direct conducted heat to roof space for transfer to habitable space by solar powered fans),
Design the house for erection in 2-3 days (rather than months), eliminating weather delays and saving money which is better used for PVs etc).
Design the house for use in a terrace development with less heat loss and no reduction in solar gain (no east/west windows).
Design the house for complete dismantling (NOT demolition) for re-use on another site.
Integrate the landscape design ( a complete house/landscape package) to maximize solar access, gaining advantage from symbiotic, seasonal changes in foliage.
ALTERNATIVE to large PV array (when natural gas becomes expensive or runs out)
Install smaller PV array to serve electrolysis unit to create hydrogen and oxygen for input to domestic fuel cell unit to create electricity and warmth (24/7) and supply the car (Energy balance yet to be proven).
Avoid water-borne toilets (too water consumptive if potable), install composting toilet (one per house) with all greywater disposed of into garden –
Alternatively:….
Retain water borne toilets (recycled water), coupled to vermiculture treatment tanks (eg Biolytix) for all domestic organic wastes and feed treated greywater into toilet cisterns and into gardens by pump.
Aim to balance water use with water continually recycled and purified within the house, minimising input of potable mains water and resultant size of water tank.
Mains water may still have to be connected but used as a reserve rather than a main supply. This may well obviate the need for a new dam.
Such a self-reliant house would have no need to rely on the traditional sewer and stormwater sewer (very big cost saving – some $60,000 / block?) if planned effectively at the outset – thus reducing land costs).
Natural gas and telecommunications would need to be connected, but eventually the gas connection could be eliminated when the supply cost becomes too high and fuel cell costs become cheaper (the break-even point may well be achieved in the next decade).
Electricity connection would still be essential as each new house would eventually become a micro-generator, supplying itself and feeding its surplus back into the grid as green energy. (My house in Mawson generates around 3MWh of green electricity every year and last year exported 187kWh of surplus green electricity into the grid.)

The EcoSolar house comes very close to the above practical ideals.