Geothermal installation on water table in 2013?

[helgdb]

Hi everybody,

We have just bought a house built in 2003 on one level, 210 m², whose high temperature gas boiler has just failed. No luck. At the same time, it is an opportunity to ask questions about the modernization of energy production in our new sweet home.
Since we want to build a swimming pool (it is in progress), we therefore said to ourselves: why not find a source of energy production capable of ensuring central heating, DHW production, and heating of the swimming pool ?

We therefore wish to acquire a geothermal installation on groundwater.

It's a summary, it's been 3 months that we cogitate on the subject, and we think that the best solution is this:

because we already have a well
because the radiators are made of aluminum, and are apparently adapted to the low temperature,
because apparently the Geo PACs are powerful enough and durable today to heat all that and last 20 years.

So I went to the Bordeaux fair (yes, I live in Merignac in Gironde) and I found 2 good craftsmen (I think) among the 12 or 13 that I consulted.

Both offer me (almost) the same solution:

an outdoor Geo PAC (in a small room that I build and insulate well)
a buffer tank for central heating, just to not make too many short cycles on the heat pump
a 300 liter buffer tank for DHW
a heat exchanger between the well and the heat pump
a titanium heat exchanger to heat the pool

The differences :

The first offers a 13 kw NIBE heat pump (the F1145) and the buffer tanks (DHW and heating) inside the house
The second offers a WATERKOTTE Ai1 Eco Touch Geo 18kw heat pump and the buffer tanks (DHW and heating) next to the heat pump, so outside. It also offers 2 small DHW tanks of 15 liters closest to the 2 Bathrooms, so that hot water arrives faster.

Between the heat pump and the heating and DHW outlets in the house, there are 10 m outside (planned buried at 80 cm) and about 10 m in the attic, in insulated pipes.

Both are at the same price after negotiation: around € 2 excluding drilling of the reinjection well, and trenches. And excluding Tax Credit.

So here, there I block, and my choice can not come out:
NIBE is better than WATERKOTTE?
Is balloons outside a good idea? (I asked it to save space in the house)

Dear new friends, do you have an opinion on the matter?
Thank you for your answers.

[raymon]

Welcome.
I find that 25 euros + trenches and the like is ruinous. A good air conditioning air water costs 000-5 euros plus the installation with a close cop 6000 to 4,3 ° instead of 7 for yours.
The difference in electricity consumption is not about to be amortized.
With the difference in expenditure you have more than enough to install an insert for very cold weather when the cop of your air conditioning drops.

[helgdb]

Certainly, but for me the debate is not about energy savings or the profitability of such a system.
If that was it, I would have continued with a simple gas boiler at € 900.

Our house does indeed "consume" ONLY € 1400 of energy per year (€ 900 of gas + € 500 of electricity).

Ridiculous.

The question of changing energy sources comes from 2 sources:

the rationalization of energy production for heating, DHW and swimming pools: why have 2 energy production when you can only have one?
the desire to be part of a sustainable environmental approach

I could have actually heated my swimming pool with an air-water heat pump, but that electricity consumption to change the heat pump every 10 years !! And why continue with Fossil energy, when I have all the resources to use renewable, green energy, inexhaustible on our scale of life?

I realized that to be eco responsible, you have to invest money, and therefore that it is a real political will.

So, if we ignore the financial return side, which in any case lapses in my case, there remains the technical choice to be made



No ?

[cortejuan]

Hello,

I did not understand everything, you say that you have a well but how will you exploit the heat of this well by drawing water and rejecting it elsewhere or by installing there as seems to indicate your explanation, a heat exchanger ?

I ask you because I was faced with the same problem 30 years ago, as I had a well I thought I could exploit geothermal energy but a quick study showed me that the flow of the well was incompatible with an extraction (renewable) calories. The well would simply have frozen. I opted for a 15 kW air-water heat pump (it lasted 23 years) and a Jotul stove for very cold days. Currently, I have a new CAP with the same principle.

But for sure, a tablecloth is great because the system becomes independent of climatic conditions.

cordially

[raymon]

Do you have an idea of ​​the total price of your installation? Is sure that the total environmental balance is better than what we say. A swimming pool can be heated with solar panels or a solar cover or with solar panels that works with the filter pump, for example:
http://www.distripool.fr/produit-1684-C ... tAod33YA8Q

It is also important to consider the depreciation of the material when calculating costs.

[danielj]

Hello. Watch out for scams. Recovering calories from water from a well is very rarely possible. It's all about water flow. Well water is generally 15 ° C. The cap can recover at best only calories between 15 (inlet temperature) and 7 ° C (outlet temperature). At less than 7 ° delta T, the COP of the cap drops to one, or even less. Any other speech is a lie. Besides, you will never be given the value of the cop for such a small temperature difference. Sometimes it is given to you, but with a small tiny asterisk, which refers you to an almost unobtainable note which tells you that the measurement does not take into account the energy expenditure of defrosting the exchangers. That is to say that we spend at this moment as much as what we recover! I speak knowingly, it's experience. I'm tired of all these scammers. We cannot reject the return of water from the cap below 7 ° C (+ -) because below you risk freezing the exchangers. So, for a well, a maximum of Delta T of 7 ° C, or 7 calories per gram of water drawn, is very little.
One kilo-watt in one hour is equivalent to 860000 calories, or 860 liters x ° C of delta t. ! Or for 7 ° C, 122,85 liters of flow per hour! And for only one Kwh! To recover 10Kwh you need 1228,5 liters of flow per hour. impossible with a simple well. You would need a stream. And again, a stream in winter is at 10 ° C, so it is almost impossible to recover calories. Good if you are on a thermal fountain, it is another thing. Otherwise it is impossible to recover calories from a single well. To know the flow rate of a well, you have to tap into it with a pump and measure the limit flow rate that depletes the well. Mine is about 100 liters per hour, and I'm lucky ... Note that a town had had a small geothermal power plant with two wells
100m (I think), that ended in a fiasco. Not profitable, everything is abandoned ...
THEN BE CAREFUL ON THE HORIZON ... A +

[Ahmed]

Helgdb, when you write:

the desire to be part of a sustainable environmental approach

is this a form of humor or do you take propaganda seriously to the point of reciting mantras?

Thank you for your testimony and your useful warnings, DanielJ ; for a water-water heat pump to work properly, a considerable flow rate is rarely possible.

I saw some that gave satisfaction because they took their calories directly from the aquifer (sands) on the edge of the Loire ... but this is indeed a very special case.

[helgdb]

@Cortejuan : if I understood everything correctly, the heat is taken in the drilling water, which leaves in my region at 13 ° C and which emerges from the heat exchanger at around 9 ° C, i.e. a delta T of 4 ° vs. With this heat, the heat pump is capable of producing hot water at 60 ° C max with an electrical back-up.

Isn't that the principle of any CAP?

@DanielJ : but then NO geothermal installation on groundwater is working in France then? And if I follow your reasoning correctly (delta T> 7 °), that doesn't work in Sweden either? Or else I didn't understand anything about your demonstration. But how can I explain the 250 clients of my supplier who are prospected only in Bordeaux and its region, all installed in water-water heat pumps on groundwater ??? There I do not understand ...

@Ahmed : for the flow rate, according to my simple calculations with a 200 liter container, the flow rate of my pump is greater than 5 m3 / h. If I haven't forgotten my math lessons, that's 5000 liters an hour, right? If I follow the calculations of DanielJ, for a delta T of 4, we would need a flow of 3 or 4 m3, so its pass?

Or do we not live in the same region?

[helgdb]

@Raymon : Well, the total price of my installation is around € 28.

AT the environmental level, if we admit that I will change my heat pump every 30 years (optimistic), and that at that time, the electric consumption is reduced to 600 € per year (that is not far from 5 Kwh per year ), and that I do not damage the water table in any way because I re-inject the water into it, so I consider that yes, the environmental balance is more than positive, right?

[raymon]

30 years is optimistic but why not. An air conditioning air water will last as long for less by investing less while being slightly less efficient.
Heating the water to 60 ° with a heat pump in my opinion the yield will not be very good.

FYI my air conditioner rair toshiba has a copy of 4,7 some models go up to 5,3!
But wood is not bad too!