http://www.guardian.co.uk/environment/ethicallivingblog/2009/feb/18/crossway-eco-home-grand-designs-kent

Apparently this is on Grand Designs this week - thought it might be of interest to the GBF crew as i dont watch tv so it will be interesting to see the response after the show.
http://www.channel4.com/4homes/on-tv/grand-designs/episode-guides/

Do want.



That is all.

Posted By: julesthe words "passive" and "house" got mentioned a lot, which is why I'm surprised to see that according to the Guardian article they've got an 11kW biomass boiler.

There was a large biomass boiler, and it was shown on one shot during the program, but I didn't see any heating system going in - no underfloor or radiators, although there could have been air heating through the MHRV system.

Posted By: julesThey did say that they expect to make an £1800 profit every year on energy generation, although quite how I'm not sure.

Yes, that confused me. There were no obvious signs of large solar PV arrays or wind turbines, and £1800 takes a lot of electricity generation on a domestic scale.

I can only assume that the biomass boiler is somehow being used to create electricity rather than heating. Is there a reasonably efficient way of doing this on a domestic scale?

You can see some kind of solar array between the front windows and the top of the curved roof. Even if it is PV, it doesn't look enough to generate £1800/year.

I was lucky to be able to visit Richard at Crossway three weeks ago just before the final Grand Designs filming. I had a two hour chat with him about the PassivHaus features. If I remember correctly it has a hybrid SHW and PV system linked to a brine phase change heat exchanger. The wood pellet boiler was installed before the hybrid system was known about and so is surplus. The timbral? roof is insulated but I suspect there is some cold bridging.
The windows and doors are Internorm PassivHaus standard. It's an amazing place. Following is his own site.

http://crossway.tumblr.com/

Just had a look at http://crossway.tumblr.com/ there are three more solar panels visible on the second page, so five in total. I would be interested to know what these are. Very impressive build though, but not for me - I'd prefer something a bit more traditional and with closer neighbours/shops etc.

I think that the central strip of the tile arch was constructed lower than the two periperal overhangs - there's a picture in the Grand Designs picture gallery which shows this. The resultant channel, forming the entire internal ceiling, was then filled up with insulation and on top of that the green roof materials.

Haven't seen the programme yet or followed all my googled links but I think I can provide some pointers for the arch. I understand it's a 'timbrel vault', which is made from layers of tiles. The first layer is held together with gypsum plaster and because that sets immediately, the vault can be built with no supports. Subsequent layers add strength and can use different mortars; the end result is very strong. Originating as 'catalan vaulting' in Spain and/or Portugal, it was popularised in the USA by Guastavino with some famous public buildings. There was a recent UK construction - 'Pines Calyx' - and the roof at this Kent house was engineered by Michael Ramage who resurrected the technique in the US while at MIT and is now at Cambridge (England).

See http://en.wikipedia.org/wiki/Guastavino_tile and http://architecture.mit.edu/class/guastavino/main.html for a good intro.

So my guess on this house is that the arch could carry all the roof loadings, though I don't know if they've dared! There must also be something providing racking resistance.

I was told the power generation payment is based on the new regulations to be introduced by the government in April this year.

StuartB, Richard Hawkes mentioned, I think, Hot Rocs. This is because his system generates electricity and hot water from one system. All I have managed to find out is as follows:-

Under the current regime, one ROC is provided for each MWh of electricity produced from renewable sources, regardless of the type of renewable energy used.
The main proposal to come out of the Energy White Paper is for Renewable Energy Certificates (ROCs) to be banded depending on the source of energy.
Established technologies such as landfill gas will have their ROC entitlement reduced to one ROC for every four MWh generated.
Other technologies, such as onshore wind, will continue to receive one ROC per MWh.
In a sign of support for less developed technologies such as offshore wind, the ROC entitlement will increase to one-and-a-half ROCs per MWh.
For "emerging technologies", such as solar power and certain waste-to-energy technologies, the entitlement will be even greater, increasing to two ROCs per MWh.
Primary legislation will be required to implement the new ROC regime and it is likely that it will start after April 2009.

http://www.powerswitch.org.uk/forum/viewtopic.php?t=10170&sid=6f90111d1230f32981e929168922a235

I hope that is of some help.

The following is comment from Richard Hawkes on the Grand Designs site.

The solar panels are actually a combined PV and solar thermal panel calle PV-T (available from Newform Energy) and you could only see 2 of the 7 of the roof. Total area = 26m2 Two panels (8m2)are at 50 degrees for optimised winter solar thermal. The remaining 18m2 are at 5 degrees for optimal summer electrical generation. A fluid in the panels cools the PV cells thus greatly increasing their generating efficiency - the extrated heat is then stored in the worlds first thermal salt phase change thermal store. This is an area the programme didn't have time to cover. For info speak to Newform Energy and The Carbon Free Group. The income from generation comes not only from electricity generation but also from the government's new doubleROCS where money is paid for the generation of on site thermal energy. The figure i stated may vary obviously but the unit rates keep changing and the subsidy terms are not fixed yet i believe. So many things couldn't be covered in the programme - it's only 49 minutes long. Credit for the structure goes to Cambridge Uni and the builder, not the architect - but i don't do the editing. Resin flooring is from South East Coatings in Faversham. We burnt the bungalow because its flimsy 1933 timber stud frame was completely rotten. The asbestos was carefully removed beforehand.

Yes the arch is insulated... its graphite polystyrene insulation, looks like neopor or similar to me... the stuff we put on externally insulated roofs then dump lots of gravel down to stop it blowing off :o)

Its then got a layer of waterproofing then another layer of tiles to make it look pretty, its clever how the roof edge design hides the thickness of the roof.

too early in the morning for anything more technical... grrr kids

Cookie

Yes ali.gill I agree... its difficult to understand the logic

See your point Tuna, just to clarify my criticism is more to do with the media portrayal of the story than the project itself. Planning wise, the crossway property has been criticized by a local resident on the comments section of the guardian or Ch.4 article as a newbuild that is far less suited to the local environment than other recent constructions.
I dont think 'meretricious' is an appropriate term for low impact straw bale housing. The planning system is far too antiquated to be applied to individuals creating a low impact lifestyle through their own efforts using traditional, low cost, labour intensive building methods.
With an agenda to construct millions of new dwellings the options are purportedly to get a plot and a minimum £qtr million mortgage funded self build or buy into the national developers eco-homes / eco-towns fiasco.
With regards Crossway i really pity their new baby as the parents are going to be spending the next twenty years stressing to work in their high income jobs to pay the large mortgage when lifestyle choice could have seen them spending more time raising their child.
I'm sure a family in a low-cost straw-bale house would manage to get their work-life balance more in tune with the needs of a young child.

fostertom, there are three layers of locally produced clay tiles. The first layer is stuck together with Plaster of Paris. The next two layers are laid at 45 degrees to the previous layer and bonded with cement mortar. There are no glulam beams. The supports for the arch are the I-beam walls. Hope that helps.