Dave Liquorice wrote:
On Sun, 31 Jan 2010 09:14:10 +0000, Tim Lamb wrote:

I doubt the pond will be good enough..may need to use soil. Any
fish
will suffer. A lot of ours are dead in a 1.5m pond anyway after
these
frosts.

But probably from suffocation from ice cover or gases from
decompostion in the pond base rather than the cold.

That's a big pond. The pipe will be on the bottom where the water
temperature cannot fall below 4deg.C. (fishes lifeline) unless frozen
down to 1.5m.

Naturally yes the bottom of a pond stays about 4C as that is the temp
that water is the densist but you will be pumping heat out of the
bottom of the pond thus setting up a circulation...

New build these days with good to high insulation levels a GSHP
system is almost a no brainer. High capital cost but *much* lower
fuel bills.



I calculated the break even price was about at 45p a liter for oil.

It doesn't do a lot unless you are using nuclear electric though, cos
otherwise electricity steps up along with the gas and oil that produce it.

capital cost £10-£15k probably.

New build its a no brainer. Retrofitting it - its a bugger. everything
up to and including hot water tanks has to change really. Larger bore
pipework, bigger heat exchangers in the tanks, bigger rads or UFH..