Joined: 28 Dec 2006 Posts: 2573 Location: New Jersey, USA
Posted: Sun Jun 05, 16 1:49 am Post subject: Zero Net Energy
Interesting. Houses that make (as much / close to) energy, balancing out what they consume. Solar power, foam insulation, efficient water heaters etc etc.
Expensive to build but costs for building this experimental subdivision are wrapped into the mortgage, balanced by significant reductions in energy consumption hence significantly lower bills.
The idea is good in principle, and certainly parts of it would adapt well to existing houses, but I do like to open windows in the summer, and have fresh air rather than air conditioning. Another thing I notice with these modern build, heavily insulatated places in the UK is that they build all the plywood and foam while leaving it open to the rain, so there must be tons of water trapped in there. Goodness knows how it comes out, but it must either evaporate out through the walls or rot them.
Jam Lady
Joined: 28 Dec 2006 Posts: 2573 Location: New Jersey, USA
Posted: Sun Jun 05, 16 1:46 pm Post subject:
The development referenced in the article is in California, Mistress Rose. And as the song says, "It never rains in California." Or very little, plus they've been dealing with a major, multi-year drought. But agree with you, could be an issue elsewhere. Foam probably injected into the wall cavities after wall / interior wall / roof in place to confine it.
It was the last paragraph that made me dubious, with the woman saying if it felt like it was getting warm she would use her smartphone from wherever she was to kick up the air conditioning. People playing with toys.
But I think it is a very interesting "real time" study. 20 houses should provide some good research / useful information.
Nick
Joined: 02 Nov 2004 Posts: 34535 Location: Hereford
Posted: Sun Jun 05, 16 1:50 pm Post subject:
I've just come back from California. I nearly drowned. And I got trench foot.
I suppose you have different requirements in different places. I stayed in Avignon in France once during the early spring and it wasn't that warm. The bedroom was built to be cool too, so it was so cold I had to wear a jumper in bed.
there are workable ways to make zero or net producing houses but they do work best if the weather/wind/mass heat source/moving water etc etc is fairly predictable and especially if energy storage is designed into the system at house or district level.
although all the components are available to various degrees of cost/energy efficiency and at least with new build good alignment/insulation/heat storage etc can be designed in the correct whole system needs to be site specific for climate, location,available energy resources etc etc
air quality can be addressed with heat exchanger systems so as air in and air out have the same temp avoiding the sealed building issues.
the integration of power,heat/cooling,energy storage and even transport energy are all possible within available tech but at the mo they are not cost effective in a few decades compared to a few decades of energy bought from the big fossil providers.this situation is changing as the tech gets better and cheaper which although not quite following moore's law is likely to out value external energy for new builds within the next decade.
retro fit will usually be a bit of a muddle but there is tech that can be cost effective for some aspects some of the time.
To some extent I suppose it is what you are used to. Having been brought up in a far from airtight house in the 1950s, when the idea was to have plenty of ventilation, I can't get used to, or feel happy with sealed houses. Added to that, I am in the great outdoors a lot, so get used to fresh air.
wellington womble
Joined: 08 Nov 2004 Posts: 15051 Location: East Midlands
Posted: Thu Jun 09, 16 10:28 pm Post subject:
When I get round to it (or win the lottery) I am going to build an earth sheltered passivhaus. It should be energy neutral and would have been cash neutral if our friends at the top hadn't slashed the solar subsidies. I don't think you can be water neutral, but there would definitely be rainwater harvesting and grey water recycling. It's on the end of a long to do list, mind.
Nick
Joined: 02 Nov 2004 Posts: 34535 Location: Hereford
Posted: Sun Jun 12, 16 9:52 am Post subject:
We are water neutral, in that we neither artificially import or export any. Ground water and rain.
I suppose I go buy some that's been mixed with alcohol at various percentages but I also smuggle some out in my bladder and leave it elsewhere sometimes.
iirc there was a goldfish that smuggled a few litres out a while ago during an unpleasantly damp confusion.
in terms of off grid independence water security is perhaps more important than energy issues and can often be addressed in parallel with energy if one is designing new build and sometimes even retrofit can include water/waste within the brief.
Nick
Joined: 02 Nov 2004 Posts: 34535 Location: Hereford
iirc there was a goldfish that smuggled a few litres out a while ago during an unpleasantly damp confusion.
in terms of off grid independence water security is perhaps more important than energy issues and can often be addressed in parallel with energy if one is designing new build and sometimes even retrofit can include water/waste within the brief.
On the plus side of the equation, the firemen also brought a billion litres with them which they applied liberally. Overall, I'm claiming we are water neutral.
We collect rain water, but the ground water is a long way down, so that would need quite a borehole. Any water we put on the garden does end up in the aquifer though, so we are water neutral, although it takes energy to get it back up to us.
wellington womble
Joined: 08 Nov 2004 Posts: 15051 Location: East Midlands
Posted: Mon Jun 13, 16 11:54 am Post subject:
I think there are a lot of misconceptions about 'sealed' houses. Passivhaus tech means that fresh air is coming in all the time, much more so than in a draughty house. It just takes the heat from the outgoing air on the way past and goes through a purpose built route rather than accidental gaps. Air circulation is a big part of the design. In fact it's a pivotal part of the design. I'm reasonably sure you can have opening windows as well and the whole point is that you don't need air con (or heating)
I'll have neutral water as well, then. Except for the booze, as Nick points out. I'll try to avoid the firemen. I want to build an 'ordinary' house, with passivhaus accreditation. For some reason they're all hobbit holes or ultra-modern industrial-look. Nothing wrong with either of those, of course but they aren't the look I would choose for my home, and people seem to think that's all you can have with Eco tech.
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