I know. The drilling company has not seen it before in 30 yrs. Just my luck,
Gusty.

Topher- 3x holes done @ 76mtrs each. I have water flowing from 1 bore but I am not sure yet how I can make best use of it. The complication is still being dealt with so I am not posting regarding the matter yet. It is not going to be settled quickly though. I am still looking forward to seeing how my GSHP performs when I am eventually in the house though,
Gusty.

Really not good at all. Boo hiss. Bv<

Rgds

Damon

Dantez,

Thanks. That is interesting. The first leak happened when the heat pump was running. The cause, was a crack in a brass fitting. It got fixed. The the pump ran for most of the winter, so it was constantly temperature cycling. Then is was shut off. Still no leak. But during a period of absence of about two months the leak happened.

I have just had a search to try and find it. It might be in the manifold, but there is no evidence of pink antifreeze. If it does turn out to be in the manifold, I will do as you suggest and ask about differing rates of expansion.

Naturally the repair is not urgent as we have all summer and autumn to pass before it becomes urgent. I will have to encourage Dominique to give it some attention.

Regards,.......Topher.
.

Grrrrrr. This morning it is 1.3 bar, yesterday it was 1.7. Will have to monitor it daily

Hi all, just came across this super forum today and just had to subscribe. The contributions here are so informative. I am currently doing a self build here in Ireland and I have opted to go for a ground source geo thermal heat pump on the advice of my plumber. From what I have seen on here and from what I am experiencing , it doesn't seem to be as straight forward as I thought it would be. My house is about 2400 sq/ft. Initially, I decided to go for an oil condensing boiler, radiators, put in the underfloor heating pipes on the ground floor (with the intention of getting a heat pump in a few years time when they may be less expensive), solid fuel stoves (one with back boiler for rads and one without) and solar panels. We worked away with that in mind but then he started on about the geothermal option as he has done them in a few jobs, my opinion of geothermal was is that its very expensive and that was off putting plus the fact it is not widely used here in Ireland (though its gaining in popularity). Anyway, when we did the sums, by taking out the costs of rads, solar panels, oil boiler, back boiler in stove, it was more or less close enough to what a geothermal setup wud cost. So I decided to take the plunge and go with it, first it was decided to go with the ground loop around the garden but the plumber then had another bright idea suggesting to go for bore holes instead as the cost of landscaping the garden and getting a track machine to move two big mounds of earth would almost cost the same as drilling the bore holes, plus bore holes give me the flexibility to do what I wish with the garden. I also know of a guy whose ground loop completely froze over in the winter of 2009 and he had no heating for most of that winter. I guess the loop was not buried deep enough. My plumber uses Thermia heat pumps supplied by the Irish distributor for them (Heatlink) and I sent my house plans to them so they could come up with a suitable system. They specified a Thermia Diplomat Optimum G2 8kw and that to me sounds fine, is 8kw output enough for a 2400 sq/ft house?. My house is of block built construction with cavity of aprox 150mm which will be pumped with a platinum bead insulation, the internal of the external facing walls will be dry lined with a 50mm insulated slab and the roof will have 150 mm metac insultation. Insulation should be adequate enough at that I think. I have kind of let the plumber work away so far with all that but I am now in the process of organising the electricity connection and had to contact the Heat pump distributer (Heatlink) for info on the starting current using soft starter, min time between starts and max current, I filled out the form for the electricity supply and opted for 16kva supply as recommended by the electricity which is more expensive than the standard 12kva supply. However, I think Heatlink quoted me for a 400 volt 3 phase heat pump and I don't 16kva will run that?, that same pump is available in 230 volts single phase so I must contact Heatlink on Monday to clarifiy that and also to check the figures that they supplied me for the electricity company, hope it was not figures for a 3 phase system! The next thing that I am in the process of doing is to organise the drilling of the bore holes and i am being asked by the drillers, how deep, how many holes, and where to locate them and sure I have no idea , so I asked the plumber and he says, go 200 meters deep ( either 1 x 200 m or 2 x 100m) keep the holes as close to the house as possible, sounds ok, then I rang Heatlink and they said max depth of 180 metres or so, 200 meters could put pressure on the heat pump trying to pump up from that depth?, he also said keep the bore holes as close to the house as possible, is there any issue with drilling doing damage to the foundations of the house or the structure itself? and he also said that if I were to use 2 bole holes, they must be a minimum of 10 metres apart which seems to be the general consensus on here. The gound itself is peaty, mud and deeper down is 'pencil's which should be ok for drilling, as long as I don't meet limestone rock. I am not sure about water maybe there is some 50 meters down, should I aim to drill where there is water? or should I avoid? I assume beause the ground is peaty and pencily that there should be no issue with the bore hole drying out, esp in the Irish climate with all the rainfall?. Nobody has mentioned anything to me on all this nor about grout in the bore hole etc. This forum has opened my eyes and I am now afraid that my job wont be done correctly as I do not have enough knowledge to ask the proper questions etc. My plumber is very good to be fair to him and he is very particular about getting things right and he has successfully installed a few of them and there are no problems. I know a few people that have geothermal and in general they are happy but it seems that a successful system is down to the installer doing a good job and not taking any shortcuts. I am a little worried and confused but an optimist Have a look on www.boards.ie and find the thread on heat pumps / geothermal there are a few interesting tales of irish peoples experiences, the cost of running some peoples systems is scary and all probably down to being not properly installed and commissioned as was mentioned on this forum

Air-source heat-pump is sounding more attractive by the day!

Thanks for all the updates...

(I bumped in to the altherma people at an exhibition where I happened to be flogging solar panels yesterday, and I'm told that things have improved a lot since I last checked and I should be able to get a decent CoP and DHW without immersion with their kit.)

Rgds

Damon

I just don't have the ground-space or accessibility for drilling boreholes without enormous heroics I think, so that unless the CoP difference is utterly compelling ASHP looks a lot less problematic.

Rgds

Damon

PP sounds like it will no longer be an issue in practice though I would need to formally apply.

I am giving Daikin another run today and will be looking at mid-winter CoPs, etc, and asking them to run a desktop simulation.

(In progress http://www.earth.org.uk/note-on-Homebuilding-and-Renovating-Show-2011.html )

But I think we're wandering away from Topher's single-handed task to educate the world about the gnarly bits of GSHP!

Rgds

Damon

Here in the UK we now have the mandatory EPC "Energy Performance Certificate" but I had to work hard to get friends buying to even consider the rating for example.

(I had our house assessed a little while ago and we were 'B' but I hope that any re-assessment would find us at 'A'!)

Rgds

Damon

Posted By: topherSo a cunning plan, if you have an ASHP which can take air from a cellar, it could be a good way of getting better results

Or a conservatory/green house when it is in the temperature sweetspot. Think we had a thread about an ASHP drawing air from a garage.

Hi Topher, thanks for sharing. It's scary stuff given the costs and hearing from anyone else that is ahead of us is a big help (even if it's not going well sometimes).

Our ground-loop manifolds are plastic (POM). I noticed though that the same manufacturer does not supply POM in the US, they use brass there instead... something to do with a big class action suite and chlorine in domestic water some years ago. I briefly considered importing US brass manifolds but of course the sizes are all wrong.

We have no joints at all outside the building but inside close to the manifolds we just have several big (42mm pipe) plastic compression joints. We did initially have some seepage (leak is too strong a word really) that seemed to be down to scratches in the pipe surface (probably from when the drill-collar was removed) but scouring/polishing the the pipe ends seemed to fix that. Right now it seems to be holding up fine but it's pretty warm so it's hardly been in use much. I guess our first winter in a few months time will tell. I can see there is a lot of value in having an installer that can stick around and be available to look at stuff.

I am also "firmly convinced" that GSHP is the way to go for us. We have a lot of groundwater flow below us. That said, the boreholes were way over the already costly budget so I would be inclined to warn anyone against that uncertainty caused by unpredictable geology. In theory our geology was very predicted.. the predictions were just worng (way over simplified) from what I can tell. I guess geology is complicated.

I do wish I could have gone for a fixed-price on the drilling. Here in the UK it's much more common to go with slinkies and if you don't mid digging up a large area I can see why - it is much more predictable. I found our groundwater flow hard to resist but the borehole problems have cost quite a big initial investment.

At least if we do have any leaks it should not be hard to see where they are I suppose.

Damon, my big concern about ASHP is that it is not there when you need it most. There would be little heat available on the coldest days when it is -10C outside. If you have a decent buffer/thermal store and a backup system like biomass (or a fireplace) and time to look after it then presumably that is no big deal (we are 100% GSHP here).

Damon,

So what COP does your favourite heat pump have at -10 degrees? Mine is 4.25 and is the same at any ambient temperature.

Does the delta COP over say 10 years save enough to pay for a borehole in your challenging borehole country?



Regards,............Topher

Topher: don't know CoP exactly in those conditions but I believe it to still be better than ~2.5 generating DHW at 50C so lower footprint than gas.

Since our entire energy bill is circa £500/year I don't think any delta-CoP would pay for the extra work, though I'm still sorely tempted from a footprint pov and I suspect that we probably have moving groundwater too.

Rgds

Damon

Posted By: topherAlthough you only pay £500/year this will increase at 5 to 15% pa compound, as we all pay for all the wind farms. I wonder if it would then be worth it.

Wages go up too and that negates the increase. You can't sell a product or service to people that cannot afford it.
If we get 5 to 15% on medium term savings in the near future that makes the FITs seem less attractive. It all balances out in the end. Supply and Demand, one of two economic theories that always holds true.

But back to the -10C and COP, this is not really relevant as it is an extreme event. What you need to calculate is the COP when you need the heat. This can be split into two parts, Space Heating and DHW and compared to HDDs for your area. Then pick a system that fits that profile best.