In an earlier contribution to this discussion,
DIY-Not DIY-Not wrote:

Hi

I'm replacing a single panel radiator with a towel radiator. So I can
select the correct size of towel rad I need to calculate the BTU
output from the original. The original rad is 730mm x 690mm and keeps
the room nice and toasty.

Is there an approximate calculation for this?

Thanks

I've just been through an exercise of re-calculating my heat losses and
estimating the output of my radiators in order to do a sanity check on my
system. Most of my radiators are single or double panel unfinned ones, which
are not too common these days - so not easy to find current catalogues of
similar ones for the purpose of finding the heat output. I have, however,
got some historical information from when I installed a system in my
previous house in about 1970, and have converted that from BTU/Hr into
Watts.

The rule of thumb which I have been using for single panel unfinned rads is
1280 Watts per M^2 (of projected area rather than total surface area) at a
Delta-T [1] of 60 degC. On that basis, your radiator would have an output of
about 645 Watts. You may struggle to get a towel radiator with this sort of
output because they necessarily have far less surface area than a normal
radiator size for size.

[1] Delta-T is the temperature difference between the room and the mean rad
temperature. Your system probably runs at less than 60 degC difference, in
which case the radiator output will be less. If you compare it with another
one which is also rated for a Delta-T of 60degC, it doesn't matter. If you
compare it with one specified at a lower Delta-T, you need to allow for
that. For example, your rad would be worth about 515 Watts rather than 645
at a Delta-T of 50 degC.
--
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!