"Tim S" wrote in message
...
Onetap coughed up some electrons that declared:

On 26 Jan, 20:33, Tim S wrote:

How?

Like U values. Probably try a heat loss type calc where the
temperature differential is the difference between the assumed floor
void temperature and the room temperature. Increase the floor void
temperature until you get the required heat emission to the room.The
BS gives temperature drop through floor construction graphs.

Ah yes - that might get an approximation - forget the air and just see
what
the board lower surface would need to be to get the surface to say 25-30
(which is a reasonable guess for UHF surface temps). I'll have to go and
dig out some U-values for wood.

Heat transfer plates would be best, the pipe would be in contact with
the floor, the pipe would have a larger effective area and the
insulation could be close to the pipe.

Undoubtedly that would be best - would rather nadger access under the
floor
though.

No-one uses copper for underfloor. PEX is preferable. The Rehau or
Uponor crimp fittings are much preferable to push-fit.

Please see this:

http://groups.google.co.uk/group/uk..../thread/9b6f3f...

Yes, I read it when it was fist posted. Utter bolleaux IMHO.

Apparently it works?...

But not very efficiently. It needs a spreader plate and a mixer to lower
the return temperature. It appears to be keeping the return temperature to
the boiler up reducing efficiency.