Can one heat a stud wall and use it instead of a radiator?

If instead of a rad of 8 sqft we warm an 80 sqft internal stud wall,
the wall surface temp rise only need be around 1/10th that of the rad.
So instead of 50C above 20 it would need to be around 5C above 20, or
25C. This is a non-problematic wall surface temperature.

Presumably the heating would be carried out by microbore with ali fins
inside the wall.

Is it workable?


NT

On Feb 5, 11:07 am, wrote:
Can one heat a stud wall and use it instead of a radiator?

If instead of a rad of 8 sqft we warm an 80 sqft internal stud wall,
the wall surface temp rise only need be around 1/10th that of the rad.
So instead of 50C above 20 it would need to be around 5C above 20, or
25C. This is a non-problematic wall surface temperature.

Presumably the heating would be carried out by microbore with ali fins
inside the wall.

Is it workable?

NT

You be using air to move the heat from the pipe to the wall which I
don't think is all that efficient but what else you'd use I'm not
sure.

wrote:
Can one heat a stud wall and use it instead of a radiator?

If instead of a rad of 8 sqft we warm an 80 sqft internal stud wall,
the wall surface temp rise only need be around 1/10th that of the rad.
So instead of 50C above 20 it would need to be around 5C above 20, or
25C. This is a non-problematic wall surface temperature.

Presumably the heating would be carried out by microbore with ali fins
inside the wall.

Is it workable?


NT

This is a really interesting idea.

Its basically UFH done vertically!

I won't be as nice as UFH, but it certainly will work.

You will need to pack the wall with insulation, to avoid heating the
room the other side, and run water pipes inside it..use standard UFH pipe..

...also use a temperature reducing system..80C water in a wall isn't
going to do the studs a lot of goos!

adder1969 wrote:
On Feb 5, 11:07 am, wrote:
Can one heat a stud wall and use it instead of a radiator?

If instead of a rad of 8 sqft we warm an 80 sqft internal stud wall,
the wall surface temp rise only need be around 1/10th that of the rad.
So instead of 50C above 20 it would need to be around 5C above 20, or
25C. This is a non-problematic wall surface temperature.

Presumably the heating would be carried out by microbore with ali fins
inside the wall.

Is it workable?

NT

You be using air to move the heat from the pipe to the wall which I
don't think is all that efficient but what else you'd use I'm not
sure.


It works fine..the key is to make sure the air is a lower thermal
resistance path than the wall to the next room (or to outside)by using
plenty of celotex behind the pipes.

In an earlier contribution to this discussion,
wrote:

Can one heat a stud wall and use it instead of a radiator?

If instead of a rad of 8 sqft we warm an 80 sqft internal stud wall,
the wall surface temp rise only need be around 1/10th that of the rad.
So instead of 50C above 20 it would need to be around 5C above 20, or
25C. This is a non-problematic wall surface temperature.

Presumably the heating would be carried out by microbore with ali fins
inside the wall.

Is it workable?


NT

It should work, in principle. I'm not sure that you can simply scale surface
areas and delta-Ts linearly though because the convection and radiation
characteristics will both be different from those of a conventional
radiator. As long as you can fine tune the actual wall temperature, it's
probably ok.

I think the tubes will need to be on metal plates bonded to the back of the
plasterboard rather than relying on convection inside the cavity, and - as
others have said - you'll have to insulate to stop the heat going the wrong
way.

You'll also have to be very careful when subsequently drilling into the
wall!
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

On Mon, 05 Feb 2007 03:07:10 -0800, meow2222 wrote:

Can one heat a stud wall and use it instead of a radiator?

If instead of a rad of 8 sqft we warm an 80 sqft internal stud wall, the
wall surface temp rise only need be around 1/10th that of the rad. So
instead of 50C above 20 it would need to be around 5C above 20, or 25C.
This is a non-problematic wall surface temperature.

Presumably the heating would be carried out by microbore with ali fins
inside the wall.

Is it workable?


NT
================================
Skirting radiators ('Finrad') used 22mm pipes with 3" square aluminium
foil fins spaced about 1" apart. You might be able to find some of these
but in any case I think 22mm would be far better than 8 /10mm microbore
even without fins. You would probably need to make up a manifold rather
than have a continuous length of pipe.

Given the area you're considering you'll probably get quite a good result
compared with skirting heaters since you'll be able to pack so much more
into your wall.

Cic.

--
================================
Testing UBUNTU Linux
Everything working so far
================================

On 5 Feb 2007 03:07:10 -0800 wrote :
Can one heat a stud wall and use it instead of a radiator?

If instead of a rad of 8 sqft we warm an 80 sqft internal stud
wall, the wall surface temp rise only need be around 1/10th that
of the rad. So instead of 50C above 20 it would need to be around
5C above 20, or 25C. This is a non-problematic wall surface
temperature.

This is what lies behind underfloor heating, large area, low
temperature (and thus ideally suited to condensing boilers or heat
pumps). Underfloor heating, though, puts the heat into the room at the
most desirable place, low down.

The other problem with your idea is that you're presumably putting a
sheet of plasterboard in front of the heat source which will seriously
impact the heat flow.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk

On Feb 5, 11:07 am, wrote:
Can one heat a stud wall and use it instead of a radiator?

Yes.

If instead of a rad of 8 sqft we warm an 80 sqft internal stud wall,
the wall surface temp rise only need be around 1/10th that of the rad.
So instead of 50C above 20 it would need to be around 5C above 20, or
25C. This is a non-problematic wall surface temperature.

It's not a simple linear relationship, the proportions of heat emitted
by radiation/convection are very different.

Presumably the heating would be carried out by microbore with ali fins
inside the wall.

Pex with ali spreader plates, as per UFH.

Is it workable?

Been done, a lot.

wrote:
Can one heat a stud wall and use it instead of a radiator?

If instead of a rad of 8 sqft we warm an 80 sqft internal stud wall,
the wall surface temp rise only need be around 1/10th that of the rad.
So instead of 50C above 20 it would need to be around 5C above 20, or
25C. This is a non-problematic wall surface temperature.

Presumably the heating would be carried out by microbore with ali fins
inside the wall.

Is it workable?

Plasterboard - thermal resistance of 0.16W/mK. For 12mm, that's around
20 W/m^2/K, or 200W/K.

For 3Kw, 15C or so.

Cement board - aquapanel - will drop this to around 2C.

If it was me, I would try to make this as following.


Take a lot of 3*2, and saw in 15mm or so deep 15mm wide cuts with a
circular saw.

Put up this 3*2 as a framework, on 60cm or so centres.

Put the pipes horizontally, zig-zagging down at the edges, with the heat
going in at the top.

Now, place 2*2 or so against the 3*2s, and screw down.

Place kingspan into the back, and seal with tape on the front side, so
no leaks can happen.
Place temporary sheets of 18mm WBP on either side, screwed securely.

Pour in a nice strong mix of concrete, and allow to set for a day or so.

On the side of each bay, place 10mm or so of polystyrene or something,
to allow for horizontal expansion.

Remove the WBP, and plasterboard the 'cold' side, and then the hot side.

This would be ideally suited for tile, though this may not be
appropriate.

On Feb 5, 11:07 am, wrote:
Can one heat a stud wall and use it instead of a radiator?

If instead of a rad of 8 sqft we warm an 80 sqft internal stud wall,
the wall surface temp rise only need be around 1/10th that of the rad.
So instead of 50C above 20 it would need to be around 5C above 20, or
25C. This is a non-problematic wall surface temperature.

Presumably the heating would be carried out by microbore with ali fins
inside the wall.

Is it workable?

Yes. We were considering building a house in Germany, and went to see
a German green builder (Ökohaus Ibach). Their office / show-home had
this set-up, but they said it was a bit of a failed experiment. Two
major problems: a) cracking in the plaster; b) picture hooks /
shelves / etc were a bit of a no-no!

On Mon, 05 Feb 2007 10:04:38 -0800, Martin Bonner wrote:

On Feb 5, 11:07 am, wrote:
Can one heat a stud wall and use it instead of a radiator?

If instead of a rad of 8 sqft we warm an 80 sqft internal stud wall, the
wall surface temp rise only need be around 1/10th that of the rad. So
instead of 50C above 20 it would need to be around 5C above 20, or 25C.
This is a non-problematic wall surface temperature.

Presumably the heating would be carried out by microbore with ali fins
inside the wall.

Is it workable?

Yes. We were considering building a house in Germany, and went to see a
German green builder (Ökohaus Ibach). Their office / show-home had this
set-up, but they said it was a bit of a failed experiment. Two major
problems: a) cracking in the plaster; b) picture hooks / shelves / etc
were a bit of a no-no!


================================
Neither problem would be insurmountable though. There are plenty of
alternatives to plaster / plasterboard and many different ways of having
pictures and shelves.

Cic.

--
================================
Testing UBUNTU Linux
Everything working so far
================================

I dont understand why you all want to insulate this wall. Since its an
internal wall, with no insulation it will heat 2 rooms, ie do twice
the work at half the price.

I realise the relationship isnt really linear, the initial calc just
gave a rough figure to begin with, which seemed to indicate it being a
runnner. Since the the required rise is so small I think we could
safely leave it to regulate its own temp with a TRV or roomstat, just
as a metal radiator does.


..also use a temperature reducing system..80C water in a wall isn't
going to do the studs a lot of goos!

Yes, thats my prime reservation. The wood would be cycled from room
temp in summer, and overnight in winter, to 80C or whatever during
winter days.

Would use of knot free wood be ok, or would it be ok if pipes were
attached symmetrically to each upright? I feel doubtful about that.

OTOH suspending the vertical pipe runs would mean the wood studs will
only see a fraction of this temp rise.

Lastly, perhaps enginered wood could be used if needed, or maybe steel
studwork.


You'll also have to be very careful when subsequently drilling into the
wall!

Well, you can drill into the studs all you want, except at the very
top and bottom where a horizontal run will be needed. Seems like a
good price to pay to have no rads or one less rad, which itself
represents a large no-drill area.

If the vertical runs are unattached, firstly drilling the shallow PB
isnt overly likely to hit them, and 2nd if it does they'll just push
out the way. It would take very persistent drilling to get through
completely unsupported microbore, and the drill goes through
plasterboard so quick and easy I dont see that happening.

So to my surprise, it looks mostly drillproof.


I think 22mm would be far better than 8 /10mm microbore

Rigid pipe would be a lot more work to install though. I was hoping to
make it an easier quicker job. If full water temp is used, not a
reduced temp circuit as with ufh, parallel microbore should be
sufficient.


Underfloor heating, though, puts the heat into the room at the
most desirable place, low down.

Perhaps we could plumb it in 2 parallel circuits, one covering the top
half and one the bottom half. The top circuit could then be turned
down or even off if desired.

Or have the bottom circuit do the work until it gets really cold and
needs the contribution of the top circuit as well. Not sure how to
arrange that ubersimply though, 2 room stats or an outdoor stat plus
electric valves would be additional expense and work.


The other problem with your idea is that you're presumably putting a
sheet of plasterboard in front of the heat source which will seriously
impact the heat flow.

While we have low conductivity, we also have large surface area and
very low output per square requirement. I dont see that as a problem.


Plasterboard - thermal resistance of 0.16W/mK. For 12mm, that's around
20 W/m^2/K, or 200W/K.

With 70C HW the PB will drop the majority of 70-25=45C.
So it will be able to conduct anything upto 45x20 W/m^2 = 900w/sqm,
and we only need a wee fraction of that.
So it looks like PB is an order of magnitude more conductive than our
minimum requirememnt for this.


Two
major problems: a) cracking in the plaster;

Presumably that might be controlled in any of the following ways:
1. Use PB with flexible joint filler with no skim - with care it may
be possible to get it looking good.
2. Use lining paper on the PB instead of plastering.
3. I expect plasters of different types have different thermal
expansion coefficients, though what they are I dont know. Perhaps we
could pick the most stable, or even mix to minimise it.
4. Use pink fire rated PB as it contains crack controlling fibres.
5. Stud materials would also need to be picked to minimise or match
expansion, but again I dont know my materials well enough.
6. Or to use cheap unstable studs maybe we could dot & dab the PB on
using a flexible glue type material, maybe even silicone beading.

b) picture hooks /
shelves / etc were a bit of a no-no!

Picture hooks are just hollow wall anchors, I dont see those being a
problem. Shelves screw into the uprights, so ditto.

I cant help but wonder whether these 2 issues might be as much down to
their particular design as the concept itself.


This looks good. Thanks to everyone for developing this one. Anyone
know more about the expansion/cracking side of things?


NT

Cicero wrote:
On Mon, 05 Feb 2007 10:04:38 -0800, Martin Bonner wrote:

On Feb 5, 11:07 am, wrote:
Can one heat a stud wall and use it instead of a radiator?

If instead of a rad of 8 sqft we warm an 80 sqft internal stud wall, the
wall surface temp rise only need be around 1/10th that of the rad. So
instead of 50C above 20 it would need to be around 5C above 20, or 25C.
This is a non-problematic wall surface temperature.

Presumably the heating would be carried out by microbore with ali fins
inside the wall.

Is it workable?
Yes. We were considering building a house in Germany, and went to see a
German green builder (Ökohaus Ibach). Their office / show-home had this
set-up, but they said it was a bit of a failed experiment. Two major
problems: a) cracking in the plaster; b) picture hooks / shelves / etc
were a bit of a no-no!


================================
Neither problem would be insurmountable though. There are plenty of
alternatives to plaster / plasterboard and many different ways of having
pictures and shelves.

Cic.

Indeed. I'd probably use MDF.

Cracking IS a problem, but lining paper would sort that.

wrote:
I dont understand why you all want to insulate this wall. Since its an
internal wall, with no insulation it will heat 2 rooms, ie do twice
the work at half the price.


Oh, fine, yif thats what is needed.

I realise the relationship isnt really linear, the initial calc just
gave a rough figure to begin with, which seemed to indicate it being a
runnner. Since the the required rise is so small I think we could
safely leave it to regulate its own temp with a TRV or roomstat, just
as a metal radiator does.


Yep.


..also use a temperature reducing system..80C water in a wall isn't
going to do the studs a lot of goos!

Yes, thats my prime reservation. The wood would be cycled from room
temp in summer, and overnight in winter, to 80C or whatever during
winter days.

That is too much. You want to keep water temps down to around 45C max,
and use a LOT of pipe.


Would use of knot free wood be ok, or would it be ok if pipes were
attached symmetrically to each upright? I feel doubtful about that.

OTOH suspending the vertical pipe runs would mean the wood studs will
only see a fraction of this temp rise.


Yup. Thats the way..come in at the wall center, and loop up and down
between the studs and then loop all the way back.


Lastly, perhaps enginered wood could be used if needed, or maybe steel
studwork.

Steel would be good.


You'll also have to be very careful when subsequently drilling into the
wall!

Well, you can drill into the studs all you want, except at the very
top and bottom where a horizontal run will be needed. Seems like a
good price to pay to have no rads or one less rad, which itself
represents a large no-drill area.


Yup
If the vertical runs are unattached, firstly drilling the shallow PB
isnt overly likely to hit them, and 2nd if it does they'll just push
out the way. It would take very persistent drilling to get through
completely unsupported microbore, and the drill goes through
plasterboard so quick and easy I dont see that happening.


Don't necessarily use microbo I;d use normal 15mm plastic UFH pipe.
You could use normal pipe clamps to hold it to the studs.

So to my surprise, it looks mostly drillproof.




I think 22mm would be far better than 8 /10mm microbore

Rigid pipe would be a lot more work to install though. I was hoping to
make it an easier quicker job. If full water temp is used, not a
reduced temp circuit as with ufh, parallel microbore should be
sufficient.

Use plastic pipe. That's whats under my floor..


Underfloor heating, though, puts the heat into the room at the
most desirable place, low down.

Perhaps we could plumb it in 2 parallel circuits, one covering the top
half and one the bottom half. The top circuit could then be turned
down or even off if desired.


Could do.

Or have the bottom circuit do the work until it gets really cold and
needs the contribution of the top circuit as well. Not sure how to
arrange that ubersimply though, 2 room stats or an outdoor stat plus
electric valves would be additional expense and work.

Another possiblity is to run hot in at the base and out at the top after
its cooled down.


The other problem with your idea is that you're presumably putting a
sheet of plasterboard in front of the heat source which will seriously
impact the heat flow.

While we have low conductivity, we also have large surface area and
very low output per square requirement. I dont see that as a problem.


Plasterboard - thermal resistance of 0.16W/mK. For 12mm, that's around
20 W/m^2/K, or 200W/K.

With 70C HW the PB will drop the majority of 70-25=45C.
So it will be able to conduct anything upto 45x20 W/m^2 = 900w/sqm,
and we only need a wee fraction of that.
So it looks like PB is an order of magnitude more conductive than our
minimum requirememnt for this.

Yep. My floor has 3" of concrete, then a foamie layer, then engineering
wood.

Still gets loads hotter under the sofa than in the middle of the
floor..that floor really does conduct through.

My only worry is going much over 50C on the internal structure.



Two
major problems: a) cracking in the plaster;

Presumably that might be controlled in any of the following ways:
1. Use PB with flexible joint filler with no skim - with care it may
be possible to get it looking good.
2. Use lining paper on the PB instead of plastering.
3. I expect plasters of different types have different thermal
expansion coefficients, though what they are I dont know. Perhaps we
could pick the most stable, or even mix to minimise it.

A thicker skim with scrim tape will sort that.

4. Use pink fire rated PB as it contains crack controlling fibres.

Its the joins, not the PB, you need to worry about.

5. Stud materials would also need to be picked to minimise or match
expansion, but again I dont know my materials well enough.

Expansion isn't great with heat..its the likelihood of huge summer to
winter humidity variations that bothers me. I hve a wall fill of pipes
and it has shrunk hugely since construction, and it moves summer to
winter..but it seems to be stabilising.


6. Or to use cheap unstable studs maybe we could dot & dab the PB on
using a flexible glue type material, maybe even silicone beading.

b) picture hooks /
shelves / etc were a bit of a no-no!

Picture hooks are just hollow wall anchors, I dont see those being a
problem. Shelves screw into the uprights, so ditto.

I cant help but wonder whether these 2 issues might be as much down to
their particular design as the concept itself.


This looks good. Thanks to everyone for developing this one. Anyone
know more about the expansion/cracking side of things?


Some. I think the key thing is to work out the real temperature you need
and then keep the water as low as temp as you can get away with.


Up to 50C I do not see a problem..over that I would be concerned.

Have a look at www.polyplumb.co.uk for useful bits to use with plastic
pipe etc.


NT

I realise the relationship isnt really linear, the initial calc just
gave a rough figure to begin with, which seemed to indicate it being a
runnner. Since the the required rise is so small I think we could
safely leave it to regulate its own temp with a TRV or roomstat, just
as a metal radiator does.

A nice idea but you cant use a normal radiator as the basis for even
rough calculations

Normal radiators are really convectors - just look at the increase in
outputs when you start adding a second panel and convector fins.

A large heated wall is likely to have very different heat transfer
properties - underfloor heating is probably a far better model to use
for rough calculations.
Robert

On Feb 5, 8:04 pm, wrote:
I dont understand why you all want to insulate this wall. Since its an
internal wall, with no insulation it will heat 2 rooms, ie do twice
the work at half the price.

You lose the option to control the individual rooms.

lid wrote:
I realise the relationship isnt really linear, the initial calc just
gave a rough figure to begin with, which seemed to indicate it being a
runnner. Since the the required rise is so small I think we could
safely leave it to regulate its own temp with a TRV or roomstat, just
as a metal radiator does.

A nice idea but you cant use a normal radiator as the basis for even
rough calculations

Normal radiators are really convectors - just look at the increase in
outputs when you start adding a second panel and convector fins.

A large heated wall is likely to have very different heat transfer
properties - underfloor heating is probably a far better model to use
for rough calculations.
Robert
Expect at best 100W/sq meter.

Possibly as low as 50W

On Mon, 05 Feb 2007 21:57:49 +0000, The Natural Philosopher wrote:

Cicero wrote:
On Mon, 05 Feb 2007 10:04:38 -0800, Martin Bonner wrote:

On Feb 5, 11:07 am, wrote:
Can one heat a stud wall and use it instead of a radiator?

If instead of a rad of 8 sqft we warm an 80 sqft internal stud wall,
the wall surface temp rise only need be around 1/10th that of the rad.
So instead of 50C above 20 it would need to be around 5C above 20, or
25C. This is a non-problematic wall surface temperature.

Presumably the heating would be carried out by microbore with ali fins
inside the wall.

Is it workable?
Yes. We were considering building a house in Germany, and went to see
a German green builder (Ökohaus Ibach). Their office / show-home had
this set-up, but they said it was a bit of a failed experiment. Two
major problems: a) cracking in the plaster; b) picture hooks / shelves
/ etc were a bit of a no-no!


================================
Neither problem would be insurmountable though. There are plenty of
alternatives to plaster / plasterboard and many different ways of having
pictures and shelves.

Cic.

Indeed. I'd probably use MDF.

Cracking IS a problem, but lining paper would sort that.

===============================
Since the OP is contemplating a rather unusual form of heating I think he
should consider making this *radwall* into something of a designer feature
in his home. This opens up all kinds of possibilities such as aluminium
frame / translucent glass / aluminium or copper sheet / louvred wood /
metal etc. The possibilities are almost limitless. Once you've called
something 'designer' you can get away with almost anything.

Cic.

--
================================
Testing UBUNTU Linux
Everything working so far
================================

Cicero wrote:
On Mon, 05 Feb 2007 21:57:49 +0000, The Natural Philosopher wrote:

Cicero wrote:
On Mon, 05 Feb 2007 10:04:38 -0800, Martin Bonner wrote:

On Feb 5, 11:07 am, wrote:
Can one heat a stud wall and use it instead of a radiator?

If instead of a rad of 8 sqft we warm an 80 sqft internal stud wall,
the wall surface temp rise only need be around 1/10th that of the rad.
So instead of 50C above 20 it would need to be around 5C above 20, or
25C. This is a non-problematic wall surface temperature.

Presumably the heating would be carried out by microbore with ali fins
inside the wall.

Is it workable?
Yes. We were considering building a house in Germany, and went to see
a German green builder (Ökohaus Ibach). Their office / show-home had
this set-up, but they said it was a bit of a failed experiment. Two
major problems: a) cracking in the plaster; b) picture hooks / shelves
/ etc were a bit of a no-no!

================================
Neither problem would be insurmountable though. There are plenty of
alternatives to plaster / plasterboard and many different ways of having
pictures and shelves.

Cic.

Indeed. I'd probably use MDF.

Cracking IS a problem, but lining paper would sort that.

===============================
Since the OP is contemplating a rather unusual form of heating I think he
should consider making this *radwall* into something of a designer feature
in his home. This opens up all kinds of possibilities such as aluminium
frame / translucent glass / aluminium or copper sheet / louvred wood /
metal etc. The possibilities are almost limitless. Once you've called
something 'designer' you can get away with almost anything.

Cic.

True. Cover teh wall with aluminium cladding as used to make containers
for shipping..that would increase the surface area and provide a
conductive path..;-)

Or better still, go to a computer recycling place and dot and dab the
wall with a plating of computer CPU heatsinks, sprayed a nice set of
colors - could do a mosaic type design.

The mind boggles

Looks like this reply got lost in the ether...


Yes, thats my prime reservation. The wood would be cycled from room
temp in summer, and overnight in winter, to 80C or whatever during
winter days.

That is too much. You want to keep water temps down to around 45C max,
and use a LOT of pipe.

Do we really have to though? UFH piping is in contact with concrete
floor, so peak temps must be limited, concrete is none too elastic
after all. But wood is. And here most of the pipe doesnt touch the
studs, so 80C water would give a ballpark about 10C stud temp rise
over most of the studs. Where the pipe goes thru the studs near top
and bottom, I'll cross my fingers and say it probably doesnt really
matter if the last 2" of wood is unstable, as it'll result in close to
no overall stud movement anyway.

Reason I'm angling for a full temp circuit is cost and simplicity, if
it is doable it would be much preferable.


Don't necessarily use microbo I;d use normal 15mm plastic UFH pipe.
You could use normal pipe clamps to hold it to the studs.

I was thinking that left hanging loose it would have a lot more
drillproofness, it'd just move out the way if drilled. Does it have to
be supported over an 8' drop at low pressure?


Or have the bottom circuit do the work until it gets really cold and
needs the contribution of the top circuit as well. Not sure how to
arrange that ubersimply though

Another possiblity is to run hot in at the base and out at the top after
its cooled down.

ohhh, yes


Expansion isn't great with heat..its the likelihood of huge summer to
winter humidity variations that bothers me. I hve a wall fill of pipes
and it has shrunk hugely since construction, and it moves summer to
winter..but it seems to be stabilising.

I suppose 2 strips of wood glued together would make a more stable
upright, arranging the growth rings in opposing directions to counter
warping, like pineboard does. Thats quite doable. Add a few screws to
back up the glue.


Some. I think the key thing is to work out the real temperature you need
and then keep the water as low as temp as you can get away with.

And I guess an easy way to set that is to turn down the LSV until it
just gives enough heat on the coldest day. Limited flow rate in the
pipe will cap the temp for all but the first bit. Microbore itself
would limit flow of course.


Expect at best 100W/sq meter.

Have you got the figures behind that? It wouldnt cause discomfort the
way over-warm UFH does.


You lose the option to control the individual rooms.

Partly, yes. Theres no easy way to balance the 2 rooms as there is
with separate LSVs if you only use the wall rad. What I had in mind
was to use it with a room that would have say 2 rads, and instead we
have the heated wall plus one rad in each room. Now the wall
contributes a lot of the heat, and the individual rads are used for
balancing.

It does of course mean you cant switch one room off and have the other
on - well you could hang curtains on it, but you cant do that in any
easy neat way.

How much of an issue I guess depends on the house and use patterns. It
wouldn't be a probem for the app I have in mind.

I guess the main remaining q in my mind now is whether we can get away
with full temp circulating water. I suspect so.


NT

If the wall rad were used as the only room heat, ie no conventional
radiators, it could be made as a 2 zone wall by wedging polystyrene
sheet in the middle of the wall and having 2 pipe circuits, one each
side.

That could open up the range of apps a fair bit.


NT

wrote:
Looks like this reply got lost in the ether...


Yes, thats my prime reservation. The wood would be cycled from room
temp in summer, and overnight in winter, to 80C or whatever during
winter days.

That is too much. You want to keep water temps down to around 45C max,
and use a LOT of pipe.

Do we really have to though? UFH piping is in contact with concrete
floor, so peak temps must be limited, concrete is none too elastic
after all. But wood is. And here most of the pipe doesnt touch the
studs, so 80C water would give a ballpark about 10C stud temp rise
over most of the studs. Where the pipe goes thru the studs near top
and bottom, I'll cross my fingers and say it probably doesnt really
matter if the last 2" of wood is unstable, as it'll result in close to
no overall stud movement anyway.

Reason I'm angling for a full temp circuit is cost and simplicity, if
it is doable it would be much preferable.



I think the air in there will get very hot..50C or more..and very hot
air is very dry air..its gong to dry the wood like anything...that's the
problem. In winter it will shrink massively and in summer it will expand
again..

I have already see this in one wall with a lot of pipework going through
it..the wall moves +-1 a mm or so summer to winter. And that has but a
few insulated flow and return pipes coming from the boiler.


Don't necessarily use microbo I;d use normal 15mm plastic UFH pipe.
You could use normal pipe clamps to hold it to the studs.

I was thinking that left hanging loose it would have a lot more
drillproofness, it'd just move out the way if drilled. Does it have to
be supported over an 8' drop at low pressure?

Probably not really..


Or have the bottom circuit do the work until it gets really cold and
needs the contribution of the top circuit as well. Not sure how to
arrange that ubersimply though

Another possiblity is to run hot in at the base and out at the top after
its cooled down.

ohhh, yes


Expansion isn't great with heat..its the likelihood of huge summer to
winter humidity variations that bothers me. I hve a wall fill of pipes
and it has shrunk hugely since construction, and it moves summer to
winter..but it seems to be stabilising.

I suppose 2 strips of wood glued together would make a more stable
upright, arranging the growth rings in opposing directions to counter
warping, like pineboard does. Thats quite doable. Add a few screws to
back up the glue.

Using steel framing would be a lot better. Or plywood.

Wood won;t shrink muhj along its lengthe - its pretty stable that way -
what will happen is that the wall will get thinner in winter..that leads
to problems at the corners with the other walls and the floor.

The floor you can sort with skirting over the floor.. butt watch out for
corner cracks - surprisingly big ones.




Some. I think the key thing is to work out the real temperature you need
and then keep the water as low as temp as you can get away with.

And I guess an easy way to set that is to turn down the LSV until it
just gives enough heat on the coldest day. Limited flow rate in the
pipe will cap the temp for all but the first bit. Microbore itself
would limit flow of course.


Expect at best 100W/sq meter.

Have you got the figures behind that? It wouldnt cause discomfort the
way over-warm UFH does.


Just dredged up from the Polylumb docs somewhere. However a typical wall
is 2 meters high and maybe 3 meters long - thats a decent enough 600W
for a smallish room. these sorts of heating systems are never rapid
response..



You lose the option to control the individual rooms.

Partly, yes. Theres no easy way to balance the 2 rooms as there is
with separate LSVs if you only use the wall rad. What I had in mind
was to use it with a room that would have say 2 rads, and instead we
have the heated wall plus one rad in each room. Now the wall
contributes a lot of the heat, and the individual rads are used for
balancing.

It does of course mean you cant switch one room off and have the other
on - well you could hang curtains on it, but you cant do that in any
easy neat way.

How much of an issue I guess depends on the house and use patterns. It
wouldn't be a probem for the app I have in mind.

I guess the main remaining q in my mind now is whether we can get away
with full temp circulating water. I suspect so.


For the cost of a temp reducing valve I wouldn't risk it. You might
experiment with reduced flow and lag the inlet parts of the pipes..

It wont destroy the house structure, but it will bugger up the decoration.


NT

wrote:
If the wall rad were used as the only room heat, ie no conventional
radiators, it could be made as a 2 zone wall by wedging polystyrene
sheet in the middle of the wall and having 2 pipe circuits, one each
side.

That could open up the range of apps a fair bit.



Yup. Better use celotex tho.

It wont be as nice as UFH, but it probably would be nicer than radiators.


NT

On 6 Feb, 21:26, The Natural Philosopher wrote:
wrote:


I think the air in there will get very hot..50C or more..and very hot
air is very dry air.

Rough calcs indicated 25C outer skin temp, and something like 5C drop
across the PB, that takes us to 30C on the PB inner surface. Air
inside will need to be above that, by how much I dont know, but given
the figures so far I wouldnt expect to see 50. But I dont actually
know.

30-40 is still dry air though, as the air slowly exchanges with room
air there will be a net migration of water vapour out of the
structure, so I guess we can expect movement regardless of where the
pipes are placed, and whether one uses 45C water or 80.

So steel uprights it is.


I have already see this in one wall with a lot of pipework going through
it..the wall moves +-1 a mm or so summer to winter. And that has but a
few insulated flow and return pipes coming from the boiler.

right.


Does it have to
be supported over an 8' drop at low pressure?

Probably not really..

Latest thinking is now to use 4' loops. Inlet pipe goes across the
bottom of the wall, looping up 4' in each cavity, then goes back
across the top. Helps the bottom be hotter than the top.

I guess the upgoing bottom loops would be suspended with wire, thus
maintaining its ability to move out the way easily if drilled.


I guess the main remaining q in my mind now is whether we can get away
with full temp circulating water. I suspect so.

For the cost of a temp reducing valve I wouldn't risk it. You might
experiment with reduced flow and lag the inlet parts of the pipes..

Another way to balance heat output across the wall is to use smaller
pipe loops at the hot inlet end. At the far wall end we might have 4'
loops, reducing to perhaps 2' loops at the inlet end. And really I'm
not sure if we need any loops along the top. The hot bottom zone will
create convection within the wall, so it might make more sense to have
2 bottom loops than one bottom one top.

If we use steel stud, roughly balancing heat output should be all
thats needed, no need to limit water temp for the wood's sake.


It wont destroy the house structure, but it will bugger up the decoration.

Yeah. I think it has to be steel. And that temp limiting the water
wouldnt really achieve much. But I'm saying all this without having
tried it.


NT

wrote:
On 6 Feb, 21:26, The Natural Philosopher wrote:
wrote:


I think the air in there will get very hot..50C or more..and very hot
air is very dry air.

Rough calcs indicated 25C outer skin temp, and something like 5C drop
across the PB, that takes us to 30C on the PB inner surface. Air
inside will need to be above that, by how much I dont know, but given
the figures so far I wouldnt expect to see 50. But I dont actually
know.

30-40 is still dry air though, as the air slowly exchanges with room
air there will be a net migration of water vapour out of the
structure, so I guess we can expect movement regardless of where the
pipes are placed, and whether one uses 45C water or 80.

So steel uprights it is.


I have already see this in one wall with a lot of pipework going through
it..the wall moves +-1 a mm or so summer to winter. And that has but a
few insulated flow and return pipes coming from the boiler.

right.


Does it have to
be supported over an 8' drop at low pressure?

Probably not really..

Latest thinking is now to use 4' loops. Inlet pipe goes across the
bottom of the wall, looping up 4' in each cavity, then goes back
across the top. Helps the bottom be hotter than the top.

I guess the upgoing bottom loops would be suspended with wire, thus
maintaining its ability to move out the way easily if drilled.


I guess the main remaining q in my mind now is whether we can get away
with full temp circulating water. I suspect so.

For the cost of a temp reducing valve I wouldn't risk it. You might
experiment with reduced flow and lag the inlet parts of the pipes..

Another way to balance heat output across the wall is to use smaller
pipe loops at the hot inlet end. At the far wall end we might have 4'
loops, reducing to perhaps 2' loops at the inlet end. And really I'm
not sure if we need any loops along the top. The hot bottom zone will
create convection within the wall, so it might make more sense to have
2 bottom loops than one bottom one top.

If we use steel stud, roughly balancing heat output should be all
thats needed, no need to limit water temp for the wood's sake.


Well that should be OK,..its not so much balancing heat that worries me
as peak heat. or rather (as you know) peak *and* continual seasonal dryness.


It wont destroy the house structure, but it will bugger up the decoration.

Yeah. I think it has to be steel. And that temp limiting the water
wouldnt really achieve much. But I'm saying all this without having
tried it.

Well Ive used demounatable steel framed plasterboard stud walls in every
office I have fitted out. Its pretty good and cheap to erect. If you get
teh wires and pipes in before th second surface is slapped on, its good.



NT

wrote in message
oups.com...
Can one heat a stud wall and use it instead of a radiator?

If instead of a rad of 8 sqft we warm an 80 sqft internal stud wall,
the wall surface temp rise only need be around 1/10th that of the rad.
So instead of 50C above 20 it would need to be around 5C above 20, or
25C. This is a non-problematic wall surface temperature.

Presumably the heating would be carried out by microbore with ali fins
inside the wall.

Is it workable?

Panels are available to go the walls, as are ceiling panels too.

With a stud wall the space between the stud can have a grill at the bottom
and one at the top with at the bottom just above the grill, finned copper
pipe. Natural convection will circulate heat and the walls will get warm
too. Simple cheap and easy, and no rads.

"Tony Bryer" wrote in message
...
On 5 Feb 2007 03:07:10 -0800 wrote :
Can one heat a stud wall and use it instead of a radiator?

If instead of a rad of 8 sqft we warm an 80 sqft internal stud
wall, the wall surface temp rise only need be around 1/10th that
of the rad. So instead of 50C above 20 it would need to be around
5C above 20, or 25C. This is a non-problematic wall surface
temperature.

This is what lies behind underfloor heating, large area, low
temperature (and thus ideally suited to condensing boilers or heat
pumps). Underfloor heating, though, puts the heat into the room at the
most desirable place, low down.

The other problem with your idea is that you're presumably putting a
sheet of plasterboard in front of the heat source which will seriously
impact the heat flow.

Evenly heat all the walls and the Mean Radiant Temperature (MRT) rises.
Most heat from UFH is convection.

wrote in message
oups.com...
Can one heat a stud wall and use it instead of a radiator?

If instead of a rad of 8 sqft we warm an 80 sqft internal stud wall,
the wall surface temp rise only need be around 1/10th that of the rad.
So instead of 50C above 20 it would need to be around 5C above 20, or
25C. This is a non-problematic wall surface temperature.

Presumably the heating would be carried out by microbore with ali fins
inside the wall.

Is it workable?

I have seen extensions that end up with cavity wall between the extension
and the main house have plastic pipes run in them and filled with sand.
Insulation was at the bottom and side to prevent heat loss Worked well. And
nice warm wall.

wrote in message ...
On 5 Feb,
"adder1969" wrote:

On Feb 5, 11:07 am, wrote:
Can one heat a stud wall and use it instead of a radiator?

If instead of a rad of 8 sqft we warm an 80 sqft internal stud wall,
the wall surface temp rise only need be around 1/10th that of the rad.
So instead of 50C above 20 it would need to be around 5C above 20, or
25C. This is a non-problematic wall surface temperature.

Presumably the heating would be carried out by microbore with ali fins
inside the wall.

Is it workable?

NT

You be using air to move the heat from the pipe to the wall which I
don't think is all that efficient but what else you'd use I'm not
sure.

I've wondered about using a stud wall. It should be no different to UFH,
spreader plates could be used, or sand/ dry mix used as a heat
transfer/storage medium. Has anyone tried it?

Many have in eco houses. One way is have two sheet of steel with plastic
pipe between. Inside and out the sandwich have a sand/cement mix. Anyone
drilling into the wall will hit the steel. Steel plate is not expensive.
Simple to do in renovation or new build.

On 8 Feb, 13:56, "Doctor Drivel" wrote:
wrote in message
oups.com...

Can one heat a stud wall and use it instead of a radiator?

Panels are available to go the walls, as are ceiling panels too.

Sure, but I dont want those.


With a stud wall the space between the stud can have a grill at the bottom
and one at the top with at the bottom just above the grill, finned copper
pipe. Natural convection will circulate heat and the walls will get warm
too. Simple cheap and easy, and no rads.

Yes it works, but clogs up with dirty fluff in time, and the vents
dont look good. What I'm trying to create is something effective,
seamless & cheap.


NT

"Cicero" wrote in message
news
Skirting radiators ('Finrad') used 22mm pipes with 3" square aluminium
foil fins spaced about 1" apart. You might be able to find some of these
but in any case I think 22mm would be far better than 8 /10mm microbore
even without fins.

Nope. A number of 8mm pipes is better than one 22mm pipe. Much better
surface air contact and hot water surface contact too.

wrote in message
ps.com...
On 8 Feb, 13:56, "Doctor Drivel" wrote:
wrote in message
oups.com...

Can one heat a stud wall and use it instead of a radiator?

Panels are available to go the walls, as are ceiling panels too.

Sure, but I dont want those.


With a stud wall the space between the stud can have a grill at the
bottom
and one at the top with at the bottom just above the grill, finned copper
pipe. Natural convection will circulate heat and the walls will get warm
too. Simple cheap and easy, and no rads.

Yes it works, but clogs up with dirty fluff in time, and the vents
dont look good. What I'm trying to create is something effective,
seamless & cheap.

Stud wall? Foam insulation at the back and to the sides of the stud. MDF
inset the same dia of the pipes from the front studs edge. Attach pipes.
silicon seal between studs and MDF. Over the lot fix Fermacell pre finished
board. High density, so higher mass. The pipes behind touch and heat the
Fermacell. See Fermacell makers.