On Sat, 08 Jan 2005 00:14:05 +0000, Andy Hall wrote:

On Fri, 07 Jan 2005 23:53:52 GMT, Phil Addison
wrote:

On Tue, 04 Jan 2005 15:41:24 GMT, Tony Bryer
wrote:

In article , Jim Alexander
wrote:
Hmmm. Preparing for "compulsory" replacement condensing boilers
in May 2005 (two jags bombshell No2) had a holiday project
trying to find some hard data on this. Failed miserably. Any
links to actual data over the full operating temperature
ranges?

Does the graph on http://www.keston.co.uk/products/celsius25.htm help?

Interesting, but 100% efficiency at 20C could do with some explanation.


There's a better graph at

http://www.keston.co.uk/downloads/pdf/cel25-b.pdf

showing the knee in the efficiency curve at the dew point and the
resulting increased rate of change with temperature.

But it still shows 100% efficiency.

ISTR some discussion about an EU way of measuring that could result in
more than 100%. I didn't take much notice at the time, thinking that was
nonsense. Is there something I'm missing or should the ASA, or at least
the CA, look into this? (the CA have been having a go at the ASA in the
latest "Which?").

They should have probably dotted the curve below about 25-30 degrees,
since that is generally about the minimum modulated down temperature
in steady state.

Hmmm... if you extrapolate their straight line it implies well over 100%
during warm up of an empty house on a cold day.

It's also possible that they have included the latent heat in the
figures...

I hope British Gas, et al, don't get wind of that or they'll be upping
the price of gas to include the value of the 'free' latent heat...
err... not!

Phil
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