[Mark Siddall]

As I suspected, but did not say earlier, Hockerton is insulated on the earth bound side.

Mark

[Mark Siddall]

A 5% slump before the project had even been completed? That sounds very worrying.

Mark

[Mark Siddall]

Oliver,
Yes. I'm an architect. Which particular subject there are a few here:
1) Design for deconstruction/reuse
2) Energy use vs. embodied energy
David O conference presentation
Forum: embodied energy discussion
3) Material toxicity/green materials

Mark

[Mark Siddall]

A cavity tray at dpc level would tackle the rain penetration risk.

Mark

[Mark Siddall]

Sarnafil (Sarna) do a Polyolefin product. That said I've heard good things about EPDM and its recylcability. My jury is out at the mo as to which is better. In terms of in-use maintenance, in case of puncture, I believe both can have new sections of material bonded to them after a few years in the sun (UV degradation has negative impact upon bonding.)
One must question where the membrane is being used. If used in non-domestic situations, and you have an external plant area then, in situations where paving slabs can not be used to protect the roof, I'm moving towards bituminous felt. The reason being that it can survive the odd puncture more readily (maintenance engineers, and M+E contractors during build for that matter, drop tools, stand on parts etc. that can perforate the membrane.)

Mark

[Mark Siddall]

Deb,
Foam insulation fitted tightly into the cavity will overcome the water issues. Also provides formwork edge to the slab over perimeter wall.

Mark

[Mark Siddall]

WRc? Is that Water Research Commission (South Africa) or is it something else? (That's all that came up on Google unless you include World Rally Championship, Worker Rights Consortium or the Women's Resource Centre)

Mark

[Mark Siddall]

Referring to the last PH Conference Proceedings the 2000W society is 2000W per person (17,500kWh/a primary energy which is slightly above the global average) though because of global warming only 500W can come from fossil fuels. It shouldbe noted that this is all energy for sustenance, survival, and transport not for buildings alone.

The PH Proceedings note that the IPCC recommends that 0.32t CO2e be allocated for buildings in 2050.

Mark

[Mark Siddall]

I undestand that it is 2000W per annum. Like most how most of the world currently survives.

Mark

[Mark Siddall]

The slab on perimeter sleeper wall detail is, to my mind, a well established detail. My Dad used to use it on his houses. I think that it was an NHBC detail (probably still current, would have to check). Why use the detail? As Nick observed, to avoid concerns about settlement (though needs re-bar in the slab.) I can see an airtightness benefit also as settlement would compromise the airtightness details.

Mark

[Mark Siddall]

Brian,
Tradis is a prefab timberframe system not a SIP system. SIPs use foam insulation as a specific part of the structure of the panel and are quite different as a result. (See other threads on this subject.)

Mark

[Mark Siddall]

It all depends upon how deep the well is. To avoid electrical pump power to the well you could go for a windmill to mechanically pump the water up. (Like they do on the farms in Australia.) If the pump for the windmill is suitably located/powerful it could pump all the way up to a roof top storage tank. Stemming from this thoughts are: –

1) Being mechanical there could be controllability issues. If it's windy you could end up with to much water being pumped to the tank, could an over flow lead back to the well?
2) From what I've heard to maximise the efficiency of the whole system seek to minimise friction by ensuring that the pipes are 50% oversized, bends are avoided. (This should also help to minimise the size of the pump.)

Hope this helps.

Mark

[Mark Siddall]

Just to ensure that the last nail is placed in the coffin. I stumbled across this…
http://www.buildinggreen.com/auth/article.cfm?fileName=160709a.xml

Mark

[Mark Siddall]

Andrew,
Have a look in the index there are a bunch of threads on the subject of ground to air heat exchange. As I understand it the COP of ground to air heat exchange (GSHX) can be up to about 20.

Heat pumps using glycol mix have been discussed elsewhere, though direct glycol mix to heat exchanger, as far as I am aware, has not. The specific heat capacity of a glycol mix would be better than air. Tying this in with some data I have on parasitic energy losses I noted that hydronic systems use less energy per kWh delivered than air systems.

I understand that PHI have recently concluded that GSHX, whilst being beneficial/useful, is not cost effective i.e. other energy efficiency measures take precedence. As it is likely that a glycol mix would require less earth works (due to sorter pipe runs) it may be that it works out to be more cost effective. But how/whether you can successfully integrate it with the MVHR I have no idea.

Under what conditions are you considering this strategy? Pre-heating or active cooling?

Mark

[Mark Siddall]

David,
Please could you exlain why it doesn't work. I imagine that it has to do with the colder ground temps in the UK (when compared to Greece and southern California) leading to greater heat losses and the subsequent impact upon radiant temps but can't really to certain.

Fuel for the Fire (geo-mass without insulation): –
http://www.greenershelter.org/index.php?pg=3
http://www.earthshelters.com/Index.html
http://www.primedesign.us/self_heating_houses/pahs_article_1.html

Why won't this work in the UK? Doesn't Hockerton get benefit from thse concepts? (Not cetain how hockerton is insulated on the retaining wall side of things.)

Mark

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