Key Post: geothermal heating system/ground source heat pump

Geothermal Un-necessary....

Hi kfpg!
I read at your earlier post that you plan to build a 300 square meter house , with the installation costs of €11.000 for the geothermal system.I really don't know if it would take 20 years to make up the difference toward a condensing boiler.From what I heard -from manufacturers -the heat exchanger will last about that long. I suppose since they work similar like a fridge that life time could be right.But a boilers life time is shorter-probably only 10 years.And it needs servicing as well, about once per year.Condensing boilers run - in combination with underfloor heating-on low output,so there is little strain on them which makes maintenance cheap and easy-the same as with the geo heat exchanger .The higher the output the faster the end of life time is reached .
If you have gas available go for it.It is slightly more expensive than oil but the boilers are cheaper and might last longer.Oil contains sulfur which turns into sulfuric acid in combination with water.that woul attack the heat exchanger.You could opt for low sulfur oil ( kerosene-a bit more expensive than homeheating oil) but that would still contain much more sulfur than gas.If you use the cheaper home heating oil you might have to neutralize the acid in the condensing water before it would be discharged to the sewer.This problem does not occur with the gas powered boilers since gas contains to little sulfur to form a corrosive condensate.It is actually so clean that you can use it in the steam iron.
Since you are still in the planning stage check with your engineer if it would make sense to use the insulation on the outside of the house instead of in the cavity.You would get more thermal heat storage capacity with thicker walls what would be of benefit since you plan to use passive solar heating-the well insulated windows on the south side.The more mass is facing the interior of the building the more capacity the building has to store the heat .The mass behind the insulation (the second wall outside) has no beneficial thermal storage capacity.It could be - I am only speculating here- that it could work diametrical to the energy demand:Since nights are longer in winter (during the heating season) than days and colder than the days , the outer leaf of the cavity wall might actually store the cold of the night.For example when in the morning the air temperature rises above the previous night temperature this warmer temperature will take a long time (together with the sun radiation) to warm up the outer wall .So during the day-when the need for heat is largest -the house would be sorounded by a layer of cold concrete.Colder than the air outside since it cooled down during the night and slow to warm up.
Another question to ask the engineer is the position of the dew point in the wall.The dew point is the place where water vapor turns into droplets.In any wall it should be as far outside as possible.The further away from the inside the warmer the feeling of the wall inside.
Some builders who choose the cavity wall overcome that problem by choosing two different thicknesses of blocks-the thinner ones on the inside and the thicker ones on the outside as far as I remember.So that the dew point would be more toward the outer wall than toward the inner wall.
 
Geothermal Justification

Heinbloed - unfortunately all your advise on block walls won't help me as blocks are progressing already, also just to clarify house size is 2800 sq feet.

Anyway having thought some more about the geo question I have already decided that I want underfloor heating so my only investment decision left is oil / gas condensing boiler costs versus geothermal heat pump costs.

My ballpark figures say 4000 euro for condensing versus up to 12000 (incl VAT) for geothermal which leaves an € 8000 extra investment / payback justification question. Considering that the house is well insulated regardless of which I go for then I have already lowered my running costs which ever decision I make.

If I were targeting a 10 year payback, then to recoup my extra 8000 investment it would have to be 800 euro per year cheaper to run the heat pump than the boiler. My only reference point is an actual users cost of €650 per year electricity cost to run a geo heat pump in a 3000 square feet house although with at best normal levels of insulation. I would therefore hope with better insulation and smaller house to be have electrical running costs of say € 500.

That means to achive the stated 10 year payback gas or oil would need to be costing me in the region pf €1300 per year in the same house, I am not sure it would be that expensive.

Has anyone got annual running costs for gas / oil condensing boilers with underfloor heating they could post to this thread, probably need to qualify costs stated with square feet or metres of house. Thanks.
 
Re: Geothermal heating system

"Has anyone got annual running costs for gas / oil condensing boilers with underfloor heating they could post to this thread, probably need to qualify costs stated with square feet or metres of house. Thanks."

Have you read this thread Underfloor Heating and checked out some of the links contained therein?
 
geothermal justification

Thanks kfpg for the correction -2800 square feet are more in the region of 260 m2 .I use about 1400 liters of LPG (ca.€400) for 96m2 underfloor heating incl. cooking and warm water for shower/taps in 13 or 14 month.So that would be around 4200 liters or €1200 in a house of your size( Tank in ownership,no rent to be payed and access to the "free"market .)
I think 1 liter of LPG contains about 7kwh's.
A condensing boiler for €4000 is very expensive,a Vokera Combi is about €1800 incl. VAT . ( Installation and certification for about €300 I guess. )
So the running costs of the geo thermal pump would be less than half of that,provided the ratio of energy prices stay the same.
Unless you have access to the gas network.Lets say you need 30,000 kwh's per year and you have a ratio of 1 :4 (investment : gain) with the heat pump you would have to buy 7300 kwh electricity for €0.127 each which is €927.Which is ca.€300 better than the €1,200 for LPG.
But natural gas is cheaper than LPG , I would say half the money.
So when you decide for condensing with LPG -according to your numbers- €8,0000 investment difference : €300 running difference means about 27 years of payback time.If you go for natural gas than this number would double-54 years.Taking into the calculations that a condensing boiler lasts only 10 years versus 20 years of a geothermal pump the pay back time would then be roughly halved ;13.5 years for LPG or 27 years for natural gas.
So 13.5 years pay back time against LPG but no pay back against natural gas-before this is achieved you need a new heat exchanger (geothermal pump)
Minus 2% or so for the cooking with the (LPG-) gas.
Now these are the numbers my home versus your home,we might have different users habits and insulation of the buildings.
 
Geothermal Justification

Thanks Heinbloed, a few comments....

I calculate 13 litres per square metre per year for your house.
((1400/13.5 mths)*12 mths)/96 m2
For my house then I would use only 260 * 13 = 3380 litres.

Your LPG seems cheap at 29c per litre (€400/1400).
I had heard more like 32c to 36c per litre. Who supplies you?
Anyway lets round up to 30c and my annual LPG would be approx €1000 (3380*0.30).

I hope for electric running costs of €500 per year with geothermal.
That gives a saving per year of €500 versus LPG.
Initial payback of 16 years which as per your comment effectively halves to 8 years as a second condensing boiler would have been purchased over that time (include annual boiler servicing costs and the payback is even quicker)

Other Factors:
I don't have access to the natural gas pipeline.
My estimate of €4000 for gas boiler may well be too high.
When the heat pump fails it won't require a full system refit or even an entire new pump, probably just the compressor.
Our insulation and personal habits of course will differ.

I assume your €0.127 figure is the night rate electric per kWh?

Loads of variables....intersting stuff....thanks again.
 
geo

I should have added another factor is I would also have to pay some rental charge for the gas bulk storage tank
 
gas tank

You could buy the tank for around € 1,000 incl.VAT and delivery.Then you need a platform to put it on, ca.€200 and a pipeline and someone to commission the installation-maybe the same person who connects the boiler.When you own the tank you are not bound to a fixed supplier.The free market is at least 20% cheaper than the standard rates published by Flogas and Calorgas and you safe on the rental costs.I figured it out when I bought mine and came to the conclusion that for 10 years rent the tank is bought-€ 8 per month.Initially the costs are higher but in a remote place I probably have to wait longer for a gas connection than the gas will last.
I don't know how it works with the nightsafer tariff-don't you need the heat during daytime?For the electricity costs you have to keep in mind that there might come a carbon tax which would hit the electric energy hardest.
And how long the existing price structure/nightsafer will last after the opening of the market is speculation.The night tariffs in Germany are increasing more than the day tariffs.The excuse of the suppliers is that they are outphasing older power plants and switching to newer gas turbines that can be switched on and off by demand.The older plants are steam engines that take a long time to heat up and cool down and are running continuously delivering unwanted/surplus power at night that is sold cheap.Better cheap than nothing the owners calculate .
Yesterday was an article in www.breakingnews.ie/
where a manager from Airtricity blamed the gouvernment for it's favoring of the ESB structures that will lead to a dependence on gas for generating electricity.He thinks that in 10 years time Ireland's electricity is generated 60%-80% by power plants using natural gas.
These are the modern type ones,not the steam engines.
So by-by nightsafer,at least for the smaller consumers.A certain amount of cheaper electricity might be available at nighttime but that would be sold to those who are willing to compete for it.I guess the aluminia industry would be fierce bidder for it.
But who knows what the future is like...
A problem with the oil tank is -in the worst case-ground water pollution.Once a well is polluted with oil it takes many years until the micro organisms have cleaned it up.In that case piped water might be necessary and in a rural place that could be very expensive.
 
Re: underfloor heating

Decided on underfloor heating in our renovation/extension.

I have a builder ready to pour foundations and subfloor, and want to make sure we get everything right (naturally!) At this point of our project the builder will dig out and rebuild our existing floors (one is old concrete with no DPM, the other suspended timber which we have already removed).

Can someone post ideal thicknesses and depths of a good concrete floor from the floor level down to the foundation along the lines of:

Floor tile: x mm
Screed containing underfloor pipes: y mm
Insulation: z mm
Concrete slab: xx mm
Hardcore: yy mm

Thanks
 
different solutions

Each floor/foundation is different.Much depends on the subsoil structure and on the building that will be erected on it.Make sure that the DPM and the radon barrier are gap less.Special tape should be used to seal pipework going through the slab.On the continent they insulate under the slab and they have the same soil temperature as we have here.Check the homepage of aerobard,I think they show on a drawing what needs to be done.Use as much insulation as you can afford,the usual 55mm are very little,an UFH system runs on low temperatures so insulation is a key point.Turning up the temperature on the boiler to get a higher output works with radiators but a concrete floor might burst and that in turn might crack the pipes .And using the soil under the house as a practicable heat storage is a builders
myth.
The thickness of the floor tiles should go in your calculation of the system,ask the provider of the UFH system for a calculation of the heat output/boiler demand.Usually these calculations are provided for free.The smaller the pipes the higher the risk of bends and blockages.But as higher the diameter as more water is to be heated up(energy!).Most manufacturers go for 12-18 mm.
Make sure that the rooms are high enough-at least one block extra to the usual 2.4 m.
 
Re: >>Geothermal heating system

Some other posts

gollmacmorna
Registered User
Ground Source Heat Pump - Is it hard on electricity?

I am planning on building a house in the next year or so I am thinking of installing a heating system based on a Ground Source heat pump.
Does anyone have one of these installed at home?
Can they give an idea of the running costs (amount of electricity used by the pump)?

heinbloed
Unregistered User
hard on electricity

I haven't got one but thought about purchasing one until I got some figures from the German Dep. of environment. They stated that there is no gain for the environment in relation to CO2 emissions , meaning that the delivered electricity that you will use has caused as much climate demage as you will save on CO2 by not using fossile fuels instead .
On the other hand - the Germans produce about 30% of their electricity from nuclear fuel and about 8% from renewables - it might be an option if you purchase your electricity from a non nuclear and renewable resource. That option we -the private consumer- don't have at the moment (here in Ireland ) unless you run a windmill or some other form of CO2-nutreal electricity generating
yourself-incl.batterys or some other form of energy storage ( hydrogen?).
Than the problem arises with "failure of system"-what damage can be caused if the pipework leaks? Usually the heat exchanging fluid is water but it needs an anti-corrosive agent mixed in and maybe also an antifreeze agent . If one of them leaks than you will pollute the ground water ( your water) .And you wouldn't know where the leakage has ocured meaning you have to reinstall the whole (soil-)heat exchanger again.Don't forget Murphys law!
The smaller the system the easier it can be fixed.The cheaper it is the cheaper it can be replaced.Between these two technical rules you have to find a compromise.
I personally decided to go for a condensing boiler (92% efficiency) powered with LPG (since I have my own well and can not "afford" to pollute the ground water).
And than there are the costs of getting a system : Keep in mind that in a free market dealing in reproduceable goods every unit (€) of money represents it's value in energy meaning when you purchase something worth €5000 you "purchase" energy worth €5000 . If you give/ spend €5000 to some one he/she will buy something for € 5000 which will contain energy/env.demage worth €5000.
It is wiser to save energy than to produce it.So it would be more money/env. wise to install extra insulation than to produce energy by means of high capital investment.Homes can be build to use less than 10kw/m2 without to much effort/capital.And this method of building lasts for the lifetime of the building,any heating appliance needs replacement after some time.

elderdog
Registered User

300% efficiency is about what is normally claimed so if you need ( say ) 12kW/hr to heat your house the thing will use about 4kW/hr of electricity.

Very cheap if you can run it on night rate...

Remember the temp of the warmed water is much lower than that from a boiler so you will need much larger radiators & pipes

In Japan a form of ground source heat pump based on a gas powered engine in commonly used. Engine rotation drives the thermodynamic pump and excess heat from the engine is put through a heat exchanger to boost the temp of the output water.

Dont think they have reached here - wonder why ?


eDog

heinbloed
Unregistered User
heat pump

I did some research, elderdog has spoken about the gas driven ones, these are the only ones that are recommended by the "German energy users "(an energy consumers organisation)
www.energienetz.com

They also say that none of the 20 (electrical)heatpumps tested by "oekotest" -an environmentally conscious consumerorganisation- has a benefit for the environment compared with condensing boilers.The worst one emits 71% CO2 more !
Only 2 models , " Hautec HWS 3048 " and "Stiebel WPWE 11 KW " had similar Co2 emissions -but only when combined with underfloor heating.Combined with radiators none is better for the environment.Another disadvantage is that their benefit for the environment (CO2) compared with an oil fired non condensing boiler will be eliminated if the heat pump is combined with a solar heating system due to the lower running hours .What sounds absurd at the first glance is logic when one realises that every investment should have a short payback time.Combining the two systems makes the larger-more expensive one-
uneconomical.

gollmacmorna
Registered User
reconsider

Thanks for the advice. The heat pump system doesn't seem as attractive with all the potential hassle involved, main concern being if something goes wrong it will cost a packet to sort out.
will probably go for a condensing boiler and loads of insulation..

Mac
Unregistered User
heat pumps

Am in a similar position to yourself. Some good comments in this post so far. Will definitely be packing extra and better quality insulation in wherever possible.

Am still not convinced whether to just go the condensing boiler route or whether the heat pump is still worth considering. One extra comment I would make is that the availability of fossil fuel reserves are on an ever decreasing timeline. This fact appears undisputed presently, with many different figures being quoted around such as 2015-2020 as being a period when oil supplies could become critical. At such a time the supply/demand will severely influence prices, add to that any interim carbon taxes etc, then a heat pump may become very beneficial. I know the electricity companies use fossil fuels also, but we would presume that on a percentage basis they would be less reliant on these fuels compared to now.

Just a thought.

Hot Dog
Unregistered User
re : MAC

Mac,

Best to head for a better climate long before we get to that stage :)


Looks like two different motivations here

1 Low cost heating

2 Save the planet from CO2

Is using night rate electricity any more harmful CO2 wise than not using it ?

Wouldnt the generators be running anyway ?

Isnt that why night rate electricity is priced very cheap ?


gollmacmorna
Registered User
No heating/ cooling system

I just came across this site last night ,
www.enertia.com

may be of interest.
High levels of insulation is definitely the way to go with argon filled low emmisive windows (such as Pilkington K-glass).

heinbloed
Unregistered User
nightrate/CO2

Good/modern power plants can be turned on /off within minutes.Electricity demand is -when uncertainties like windfarms are taken in to account-calculate able for about 90 minutes.We have only 2 % of our elec.generated by windfarms so we don't have to take this "uncertainty" into account because there has to be always extra power available in the grit anyhow.
To the point:every unit of electricity consumed damages the environment.Using "nightsaver" electricity means using electricity that is generated by ineffectiv power plants -those that have to run day and night because it takes to long to switch them on and off on demand.
By purchasing "nightsafer" you subsidise dinos that would have been dead because of marketforces(PROFITABILITY) since a long time.
Buying nightsafer means you subsidise the daytarif -the
profit that these old power plants generate are made at peaktimes of demand.Some,if not most, of our powerplants operate on less than 50% efficiency,in generating terms speaking.Taking into account the environmental damage that is caused by transporting the fuel to them,the (environmental!)wars that are fought to get that fuel and the loss between powerplant and consumer the bill looks very bleak for the environment,I go so far to say if we don't purchase the "nightsafer" no more than several of these dinos would have to switch off for good.Of course they would have to be replaced by others to cover peak demand but investors-not job creators like the gouvernment-would look after that so they get plenty of their investments back,plus profits of course.In the old monopolistic times it didn't matter how expensive electricity was produced , it was take it or leave it for the consumer.With an opening of the market
very soon
(a) the price for the nightsafer tariff will rocket(see other free markets)
(b) and the price of electricity in general will go up since the bangers which had been paid for long ago will be scrapped and to be replaced by new ,capitalintensive ones.
Just look around in the rest of the world where the free market in electricity sales had been introduced.
If ou don't understand something feel free to ask,some information can be extracted from the ESB website as well.
 
Aerothermal

Has anyone heard of Sweco in Wicklow. They supply an aerthermal system which they say is more suited to the \irish climate.
 
Re: >>Aerothermal heating system

I have spoken to SWECO about their Aerothemal Sytem.
The type of low energy house I am building could be heated by the SWECO 7 (7.1KW output of heat).

This will heat radiators hot water etc. using 1.3 KW/hr of electricity.

At 11c per KW/hr ( If I am correct??) for daytime usage you could have 6 hrs. of heat for example for 6 x 11c =66c ??? If this is correct

Nightrate electricity while it still exists is 4.5c per KW/hr.
so timing the heat pump to come on to avail of the night rate to heat up your house would make sense.

The system is fairly costly though at about €8,000 including installation commissioning etc.

I am still in two minds about either getting one of these or a pellet stove/ boiler.

I intend to insulate the house to practically zero heating standard so it will probably boil down to convenience of use and long term performance ...in this case the heat pump could be worth considering
 
Aerothermal heating system

Make sure you get what you need.And be careful with business partners who claim that using electricity "creates no emissions" as sweco/ie. does.
Misleading advertising,several court cases in Germany had been decided in favour of consumer organisations and competitors that this claim is wrong.
Make sure you need a heat output of 35 degrees,that would be good enough for an underfloor heating but not for radiators.
Using a heating means using it roughly 150 days per year on full demand,100 days at 100%,100 days at 50%.
That gives us 150 days the full costs:1.3kw/h x 24h x 150 days =4680 kw at a price of € 0.1385/kwh= €648.18 .That is a lot,more expensive than all other forms of heating except direct electrical heating.Using the night saver rate in the calculation is not viable,you need the heat during the day.The night is short and the extra costs of the night rate meter (€18 per two month) must be included.Plus the costs of domestic hot water at about 1.5 kw per shower.Two adults twice a day for a year for about 1000 kw.
The sweco aerothermal heating system is a totally wastefull way of heating , in my opinion.
If you really want an aerothermal heat exchanger than go for a gas driven one,there are many available,they run cheaper at about half the costs compared with electricity.
Sweco gives a gain of 35 degrees from a source that is 0 degrees cold.Are you sure that you need 35 degrees when it is o degrees cold outside?And when it gets minus 5 degrees,doe you still have enough output? Demand a full calculation spread sheet before you decide signing the contract.
 
Geothermal - Plan B !!

For a long time I have been committed to going with a geothermal heat pump system. As it is getting closer to decision time now I have had a site inspection done and following this I now have some doubt in my mind.

My site has a very high water table (less then 0.5 metres below surface in wettest part of year) combined with poor percolation results from the ground ( a result of daub / clay type soil).

Therefore it is questionable as to how efficiently the ground source collector will draw heat from the ground. A principle of the collector is that it gains heat from rain water / moisture percolating down through the soil and passing away from the pipe subsequently. In my case it seems this principle may not be successful for the reasons stated above.

I am posting this not only to share my experience with others but also to ask now that I have to consider a Plan B approach to ask

1.What are the most efficient oil and gas condensing boiler models and manufacturers readily available on the Irish market?

2.Are any specifically designed / configured to run underfloor heating?

3.Is either oil or gas condensing preferable above the other?

Thanks !!
 
Plan B ?

The idea of a ground thermal heating is to collect heat from the ground,not from the surface , kfpg1 .
The ground should give you a temperature at around 8 degrees,but the surface could freeze during winter.At least the farmers are not allowed to spread slurry once the top (soil) temperature drops below 0 degrees.And that is during winter,when the heating demand is high.Therefore a ground source heat exchanger should be dug in the ground at least 1.5 meters deep to guarantee an even temperature and plenty of it.The winter can be long.The longer you run the system the colder the surrounding ground will get.And therefore it is an advantage to have the heat exchanger surrounded by ground water and not the opposite.Water is a good heat transmitter(central heating!) and will increase the potential of a ground source heating pump.Some use lakes and rivers to take out the energy,some use ground water.Using dry soil would demand a larger loop to increase the surface of it.And the dry soil would cool down faster.
The cheapest (gas) condensing combi boiler I have seen was a
Vokera Synthesy 24 kw (which is very big,probably over sized for your home)for €1400 incl.VAT from OB Heating in Cork,price from October '04.But not a modulating model,these would cost an extra €400.A modulating boiler will save you another 5% or so since it does not fire up as frequently as an on/off model.During the firing-up/start process boilers are wasting energy.All condensing gas boilers can be fitted for natural or LPG gas at little or no extra costs(Vokera does that for free).LPG is cheaper than natural gas-once you own your tank.
As far as I know there is only 1 modulating condensing boiler running on oil available, called maxi something.
I could find out for you.Or try yourself at www.sedbuk.com/
Have you figured out what it would cost to go solar in combination with super insulation/passive home?
Get your engineer to provide you with a heat calculation sheet,he is obliged to do that.Than decide for the heating system.The smaller the boiler output(kw) the better for your wallet and the environment.And remember that you would hardly heat the entire home during the same time,so a home with a total heat demand of for example 10kw might need only 8 kw for most of the time.
If you like to make your boiler an optical feature check
the Vailant boilers,top of the range boilers,small and smart.Not the usual bold box shape.Something for the entrance hall.
 
Geothermal - Plan B !!

Hi Kfpg,
We also had to resort to a plan B when we realized that we hadn't enough depth in the soil for the geothermal pipes. We are drilling instead, similar to a well, and using the closed loop system. The principle is the same and we feel the extra cost will be worth it. We are also planning to install a wood pellet stove for additional heat in the house.
M.
 
Plan B

Heinbloed, thanks as always for your kind, considered and informative replies, I always look forward to them.

I think perhaps you miss one critical point about my situation - the collector area is in ground which has extremely poor drainage / percolation.

This means that the collector will rob the water (essentially "still" water) of all its heat - increasing the likelihood of freezing- the water is not then replaced as it has nowhere to go !! it stays there in the ground. In a typical collector this water drains down vertically and is replaced by new water (rainwater) filtering down from the surface which provides new thermal energy. Of course the ground does have thermal energy in addition to water in the ground but in my case the high water table means this aspect of the collector is critical.

In a lake or river the surface area for collecting the suns energy is abundant and provides continuous energy for the collector as it flows over it. This is not the case in a field with lots of water underground but with no flow ar percolation.

Any thoughts?
 
Re: Geothermal - Plan B !!

Hi kfpg,

Who exactly has suggested to you that a high water table is a problem?

As I understand it, one of the principles of using a ground loop is that ground temperatures (at a depth of at least 1.5m) are relatively stable year round, regardless of the geological characteristics of the site. So even if you have a lot of water underground, it's relatively warm.

I don't believe the ground loop would draw enough heat out of the ground to significantly lower the ground temperature and cause freezing around your pipes -- surely geological heat transfers up from the center of the earth as well as down from warm rainwater etc.

Did this water table suggestion come from the supplier of a more conventional heating system?
 
Geothermal-Plan B

I agree with extopia.If the water was stagnant in the ground it would smell very rotten,but that is beside the point.If it was stagnant you would be living in a lake without outlet.No groundwater is stagnant.If water penetrates the soil it goes somewhere.The only exemptions to this rule are prehistorical deposits as in the lower Sahara where there are large deposits of water 6000 years old or even older.And the other exemption are fresh bomb craters where the surrounding soil is heavily compacted,but even that is only temporary since the chemical influences of various types of soil mixed with each other (plus the effect of sunshine)will sooner or later loosen the crater walls and make the soil penetrable.Europe and Vietnam would be still flooded if that did not happen.
Make sure you have the right percolation test done,may be not by the company that wants to sell you a biocycle tank.Contact the supplier of a heat pump system and tell them the situation.
The only way that the surrounding soil of the heat collector area could freeze was if the dimension
chosen was much to small,i.e. not enough pipe work in the soil resp. the pipes are not spaced at the correct distance.But before it freezes you would realize that the pump would be working harder and harder since it would try to make up for the decreasing output of heat with more and more pumping .Like a fridge when you leave the door open.I heard from owners that they switch off the geothermal system during summer -dom.warm water made in the meantime with electricity from the grid or a solar panel-to give the collector area a "rest" to warm it up from below for winter's heating demand.
But the deeper you dig the warmer it gets ,about 1 degree for each 30 meters.That is -more or less- the same on the entire globe.Except you drill in Iceland or directly into a volcano(smiley).The heat for the geothermal ground pump comes from the center of earth,the presence of water would make it easier to "tap" this heat-if standing or flowing it won't matter in principle.
 
Re: >>Geothermal heating system/Ground Source Heat Pump

I see that someone is using pumped insulation in their build. My architect has specified 60mm Xtratherm XT/CW insulation to comply with building reg. with min. U-value of .27, is pumped insulation better or what?
 
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