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GSHP for small gardens?
Posted: Fri Jul 13, 2007 3:11 pm
by Cheezy
I seem to remember that GSHP used to be bored down into the ground and the ground water used to run a heat exchange.
Is this still a possibility for small gardens where we can't fit large loops of under ground coils?
Any one?
And what are the relative costs. For drilling , fitting and running
(Martin

)
THis would be for a retro fit into an old, cold Victoria terrace. down stairs under floor heating
Thanks
C
Posted: Fri Jul 13, 2007 5:55 pm
by Martin
usually a total waste of time unfortunately!
To get a decent sized ground loop going deep is going to cost an arm and a leg - the upheaval in a small garden would be colossal, and most of all there's a "fatal flaw" in heat pumps that renders them useful in only very few circumstances - yes, you may get 3 or 4 "free" units of heat, for every one unit put in..............BUT what they don't tell you is that the unit of energy it uses is the most expensive (electricity) at around 10p.........if you're on town gas at 2p unit..........do your own sums! (it ends up costing you MORE than using gas, having spent a small fortune!)
About the only circumstance I would recommend them is on a new build where you can put in underfloor heating to use it at it's best - and then only if you're generating your own power........

Posted: Fri Jul 13, 2007 6:35 pm
by Martin
ps, for a typical terrace house I'd go for the following
1 - Insulate till you can't move
2 - Solar Hot Water (should give you all your hot water March-October)
3 - Woodburning stove with saddle boiler - to save your normal central heating from firing up all the time
4 - Construct WW2 type bomb shelter in back garden (for silencing), and install a modern copy of a Lister to give your electricity (grid-tied), run off waste vegetable oil - heat recovered use to warm thermal store* in home!
If you're going for 2&3, suggest doing both at the same time, or telling the solar engineeers that you're going to have another heatsource later, then they'll leave an unconnected coil in the thermal store for later use - it'll save changing the tank twice!
* Thermal store is a posh way of saying a large vented hot water storage tank with loads of insulation, the heat being transferred by coils inside the tank fed from the boiler/woodburner/solar system - you need to specify how many when you have one fitted (if in doubt, leave a spare, it only adds about £60 per coil)

Posted: Mon Jul 16, 2007 1:47 pm
by Cheezy
Thanks Martin.
I've had an insulation inspector round last week to check out our house.
The house is one of those Victorian terraces which has the kitchen/bathroom extended out from the house. THis has little insulation in the slate covered loft, but is a really difficult to get into.He basically said due to health and saftey he couldn't send his lads in to the loft as the access wasn't good enough,and the numerous water tanks still up there (I think they must have removed slates to get them in) were also a hazard preventing installation!.