"Tim Lamb" wrote in message
...
In message ews.net,
Doctor Drivel writes

With a largish river 20m away I'm more inclined to a heat pump. I don't
know if o/p temperatures would be high enough for under floor heating
but I will bear it in mind for any future change of use.

A water sourced heat pump extracting from a moving stream or river is by
far the best system.

So what exit temperature could I expect from the heat exchanger

Depends on the compressor, but enough to supply DHW, so 55-60C is achievable
all year round.

and is this high enough for under floor space heating?

It will run rads, as long as the stream
or river never drys up.

There is also the issue of Environment Agency consent. I have not
investigated their views on this particular river (the Lea) but know they
normally expect a licence/payment to abstract and return water.

You are just extracting heat. Making the water cooler, to therm, may affect
wildlife. If the river moves quite well, then this should not a be a problem
at all. Also, a reversible heat pump can dump heat into the river too, and
cool the house.

It may be acceptable to draw from a shallow well and return via a soak at
some distance.

If you can do this without permission and there is enough water being
replenished in the well, all fine and dandy. All you need is a pump to
extract the water and all the heat pump equipment can be on the surface.
None of this is cheap at all. Look into insulating the place up to the
rafters and making the house air-tight. Then only a small LPG, or electric
heating system cost £50 ayear or so to run, may be required just to raise
the temp.