On Sun, 13 Mar 2005 11:35:08 +0000, Nick Atty
wrote:

I want to add an additional radiator to a loft converted to a bedroom.
I think the radiator fitted is just about adequate for the room, but:
a) SHMBO likes her bedrooms about 10 degrees hotter than I do

Are we talking about degrees Celsius or the deprecated Fahrenheit?

You've used metric everywhere else, so I assume Celsius, but 10 degC
seems like a lot.


b) the radiator (which is on the only vertical wall in the room) is
behind where we have the bed-head, so it's hard for the air to get out,
and the bed tends to push up against it, boiling my head in the night.

Along one side of the room is a suitable surface for putting a long,
thin, radiator - it's about 4 metres long but only about 20cm wide.
I've got easy access to the heating pipes at either or both ends of it.

From my canal boat experiences, I know about "finrad" - a copper tube
with thin metal squares attached to it, which is very efficient but
looks nasty, cuts you if you brush against it, and collects more dust
than a dyson.

A prolonged google has only turned up some "designer" radiators, but at
400quid a metre, this is more than I really want to spend - by at least
one order of magnitude.

Currently my thoughts are running to a loop of chrome tube, on chrome
stand-offs, so I end up with about an 8 metre run, with feed at return
at the same end. But the joints are going to have to be compression and
will look a bit nasty with 6 inline couplers as well as the elbows at
the end.

How much heat is this likely to give out?
Will 22mm tube work better than 15mm (greater surface area)?
Can anyone think of anything better at a sensible price?
Or any improvements to the idea?

Before you do anything, you will need to calculate the actual heat
loss. You can use the Barlo program to do this, or drop me a mail
and I'll send you the Myson one.

You need to take account of surfaces, insulation and air changes.
There can be huge differences resulting from these, and unless you do
the sums reasonably well, you run the risk of being hugely out.
Also, don't forget to take account of the intended temperature drop of
the radiator. For a conventional boiler this is 82 degrees in and 70
out. Less for a condensing boiler. Radiator data sheets work on
the basis of higher temperatures so for th 82/70 situation, you need
to derate using a factor of 0.9

Myson, Stelrad and Barlo make skirting radiators that would fit your
dimensions. There are conventional ones as low as 30cm.


If you make your own and only use tube with no fins, I think it is
highly unlikely that you will get enough surface area to release the
heat that you will need. 22mm is going to be better, but I suspect
when you do the sums, you will find that the results are still way out
- my guess would be by at least an order of magnitude.




--

..andy

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