"John Stumbles" ] wrote in message
...
[Apologies for reposting but I sent this one out yesterday and oddly,
although I can see it on Google, it hasn't shown up on my local news
server
(text.news.ntlworld.com), so I'm wondering if the lack of followups is due
to others not having seen it either rather than (or perhaps as well as)
no-one finding it faintly interesting or being able to help :-)]

Anyone know where I can get figures for calculating (allright,
guesstimating
:-) rates of heat transfer through pipes for a diy heat store heat
exchanger? I'm planning to hang say a 25m coil of 10mm table Y copper pipe
in a tank connected to the CH primary and wondering what rates I can
expect
to get water out at given inlet and outlet (and tank) temperatures.

Obviously I can suck it & see but it'd be nice to have some sort of
theoretical figures to start with (and encourage me to actually have a go
with the idea :-).

tia

John Stumbles
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Most heat exchange properties can be calculated using Newton's Laws on
Materials Cooling, The Fourier Modelling Equation and The Stephan-Boltzmann
Rule, all of which give calculations for flow rate and flow restriction
against surface area. I think that they all roughly state that a longer
wider diameter (greater surface area), higher temperature pipe, with a slow
replenishing flow gives the best results.

The same equations are used in the calculations of heat sink properties on
electronics equipment, which I think a few people using the group will be
able to give more details of.


---
BigWallop

http://basecuritysystems.no-ip.com

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