solar heating a concrete slab? - can you passively heat a cocrete slab?

[jeremy white]

I'm about to build a passive solar home and am investigating ways to passively solarheat a concrete slab with sources other than direct sunlight. i.e. hot water, gravity (or electrically) pumped through the slab. Does anyone have any experience, ideas or links for this kind of application?
thanks jeremy

[Chook Nut]

hi jeremy,

i read that George Bush's ranch has state of the art solar equipment and also through the slab.

do a search on Google to see what you can come up with i did one using the words 'george bush ranch efficiency' and got a little bit of information.

it may lead you in the right direction. i would say it would be very expensive to do something like this.... using the sun directly may be more cost effective even though its no exactly what you are after.

let us know how you get on .

cheers

Dave

[d_donahoo]

hey jeremy.

hydronic heating of slabs is very popular. basically just put pipes in before you lay the slab...and then you can hook it to a wood stove water jacket or solar hot water system...there can be problems - pipes burst or block etc...but overall they are very effective.

i'm sure you'd find info on an owner builder list -

try... http://www.byohouse.com.au

cheers

[Jeff Nugent]

A big problem with pipes in concrete is the movement as the pipes heat and cool. They abrase against the concrete and finally burst, my plumber friend tells me.

[d_donahoo]

yep jeff.

one of the definite downsides...

but my understanding is there are ways of engineering around this.

cheers

[jeremy white]

Thanks for tour help people.
Would plastic polypipe be a viable option??

[d_donahoo]

wow. now that has put an interesting idea out there...

i guess you could give it a go...

i'd be doing some testing first though - a rather expensive mistake that could be...

one thing i think worth considering is the energy input into heating the floor this way - compared to the output...several homes i've visited in central victoria - mudbrick, passive solar have no floor heating - and probably would only use it on the coldest of winter days -

we are building out of strawbale - and heating the floor would probably make the whole set up too hot.

cheers