Heat storage

[bernardd]

This system works for very well insulated buildings, with solar collectors in Switzerland.
But storage is not interseason because the 2O5m3 tank does not have thermal insulation retaining its heat from summer to winter (4 to 6 months).
In addition, its size does not allow winter heating with the heat stored in summer !!...

Insulated balloon storage will not do as well over 6 months !!
At more than 3m deep the earth has this property of keeping the heat for years, ie T equal to the average of the year !!

I totally agree with you on underground storage, but the mole is just missing :-(

Exactly on this idea, I had spent time looking at small drills to drill vertically over less than 10m: it would be as usable as horizontal tubes but easier to do: but I did not find machines capable of do this at an effective cost at the moment.

If someone has an idea ?

Otherwise, this example of an internal tank is magnificent! Losses remain in the building, therefore 100% storage efficiency!

It does not need to last 6 months: it suffices for the longest period without the sun, at a rate of 93 kWh per m3 of water at 80 ° C compared to 10 ° C.

[dedeleco]

This company does this type of directional drilling for different activities including geothermal energy and its simple technique:
http://www.gendrylocation.com/Pub/geothermie.htm
I don't know the price but

Geothermal energy
... Or the installation of sensors buried by horizontal drilling
Horizontal drilling is a technique that has proven itself for twenty years in France and for thirty years abroad.
Gendry Service Location (GSL) has extensive experience in directed drilling since 1996.
We want to adapt, right now, our know-how to environmental protection; we do it by geothermal energy.

DIRECTED MULTI-DIRECTIONAL COLLECTION

Principle...
- Compact directional drilling system.
- Rods: length 0,5 m. and diameter 45 mm.
- Drilling head: diameter 70 mm.
- Machine: width 80 cm, length 180 cm.
- Type of injection: water (foam) or air.
- Drilling: maximum length 50 m. and depth: max. 15 m.

Benefits...
- No trench (only a pit for collectors).
- Land not destabilized at the end of the site.
- Execution speed: 250 m. drilled per day, i.e. 500 ml of geothermal probes placed per day.
- Power: 4 tonnes of thrust and / or traction.

It has large, rather bulky resources for large sites too.

Geothermal energy sees only the heat pump, while the storage of solar heat from summer to winter is much more interesting, more EDF, nor dependence on heat pump with limited lifespan (the 8 year-old heat pump fluid becomes prohibited and it is necessary to change the heat pump, for me, because maintenance is impossible by refilling the fluid !!)

In one day 250m or 20 boreholes at 12,5m or 10 over 25m under the whole garden, so in one to 5 days, we obtain most of the underground tubes to grid a volume of 10m to the cube (1000m3) to be heated summer to winter (on ground without circulation of underground water, which can be blocked by injecting underground product blocking pores and cracks).
In winter, with the thermal diffusion over 3m on the periphery the hot volume becomes 10 + 2x3 = 16m in the cube = approximately 2197m3 and therefore the temperature difference is reduced by 2,2 or by 13 + 40 ° C = 53 ° C in summer on 1000m3, we go to 13 + 40 / 2,2 = 31,1 ° C sufficient to heat without heat pump at 20 ° C, by air circulation on exchanger, like the heat pump, but without the heat pump, which is replaced by summer heat. !!
This heating summer to winter becomes free in perpetuity, without changing or remaking the whole house.
The price certainly depends on the number sold when the set works with solar thermal collectors (function of the basement).

The Swiss solution with 10 or 20m3 of buffer tank in the middle of the house (ie 10 to 20 tonnes in the house) is attractive for a new house, but requires rebuilding the old house !!!

[bernardd]

The Swiss solution with 10 or 20m3 of buffer tank in the middle of the house (ie 10 to 20 tonnes in the house) is attractive for a new house, but requires rebuilding the old house !!!

It is complementary with low temperature underground storage. It provides a high temperature solution without loss: perfect for domestic hot water and also for the process. This could almost allow a large part of the heat used in the kitchen, at 80 ° C or 90C, you can cook an egg and many other things without problem.

One can imagine tanks like columns in the central rooms, like the old mass stoves: large water storage radiators. But you need the resistance of the floor :-)

Geothermal energy sees only the heat pump, while the storage of solar heat from summer to winter is much more interesting, more EDF, nor dependence on heat pump with limited lifespan

Totally agree !

In fact, what amazes me is the ability to convey a complex solution as obvious to the majority, an "established fact", when there are simpler solutions. Doesn't that remind you of some herd behavior on the interpretation of emotional events?

In winter, with the thermal diffusion over 3m on the periphery the hot volume becomes 10 + 2x3 = 16m in the cube = approximately 2197m3 and therefore the temperature difference is reduced by 2,2 or by 13 + 40 ° C = 53 ° C in summer on 1000m3, we go to 13 + 40 / 2,2 = 31,1 ° C sufficient to heat without heat pump at 20 ° C, by air circulation on exchanger, like the heat pump, but without the heat pump, which is replaced by summer heat. !!
This heating summer to winter becomes free in perpetuity, without changing or remaking the whole house.

Of course, and it would certainly be necessary to recover the heat, ie cooling, by the periphery, to "suck up the leaks"! In this case, directional drilling would be a very good solution.

However, the problems of a wet basement must be mentioned: in the event of drying and shrinking, the foundations can react badly. And in case of non-drying by renewal of the water, all the heat leaves with.

This company does this type of directional drilling for different activities including geothermal energy and its simple technique:
http://www.gendrylocation.com/Pub/geothermie.htm
I don't know the price but
...
In one day 250m or 20 boreholes at 12,5m or 10 over 25m under the whole garden, so in one to 5 days, we obtain most of the underground tubes to grid a volume of 10m to the cube (1000m3) to be heated summer to winter (on ground without circulation of underground water, which can be blocked by injecting underground product blocking pores and cracks).

An article talks about 170k € for 230m, but to pass a 55cm tube.

Starting from an operator + machine price of € 1000 / day, we would arrive at € 4 / m: that would remain expensive. The current standard drilling is at 10 € / m.

It would be necessary to equip a machine with several parallel heads, for example 4: the same team would drill 4 times more without necessarily more problems, for the same price.

[chatelot16]

as a mass of storage I think that the large number of drilling to use the earth will cost more than a large tank, and it will be worse if it is also necessary to inject products to seal the soil and avoid heat loss by the water ...

except that the large tank can also be used as a tank!

you always talk about time and distance of heat diffusion: but this figure is not what interests me! what proportion of the stored energy will be lost? whether it broadcast 1m or 10m does not really tell me

of course if the tank is an area of ​​land 100m in diameter and the diffusion distance is 1 meter we are sure that the loss is low

if I replace this area of ​​100m of earth with a smaller water tank, thanks to the better specific heat of the water, the same distance of diffusion in the earth will represent a much smaller loss of energy since the surface of the reservoir will be smaller than the area around the land area

you said once that in a large thickness of glass wool the diffusion distance would be roughly the same as in the ground: this is proof that this diffusion distance is not the important criterion: it is largely evident that the energy lost by diffusing in 1m3 of glass wool is considerably lower than in 1m3 of earth

it is obvious to me that to make a good thermal storage a homogeneous material is worth nothing: it is necessary to put a materials with strong voluminal heat in the center, and an insulating materials around

Can a bad free insulator like earth be more profitable than a real insulator?

[dedeleco]

However, the problems of a wet basement must be mentioned: in the event of drying and shrinking, the foundations can react badly. And in case of non-drying by renewal of the water, all the heat leaves with.

Very important, this is why I see these boreholes in the garden and not under the old house, which risks to crack with the variations of temperature and humidity of the basement (as for the drought of 2003).
If the water circulates in the underground, source, injections of solidifying product or cement must be made and plugging the cracks in the periphery from the peripheral boreholes.
For large civil engineering works, these technologies are very advanced, but their cost is excessive for small-scale works.
It would take the mentality of the Japanese to adapt and lower prices in large series (drilling robot), as they did to switch from radars. To microwave ovens deemed impossible in the 1950s to 1960s by US magnetron specialists !!

Starting from an operator + machine price of € 1000 / day, we would arrive at € 4 / m: that would remain expensive. The current standard drilling is at 10 € / m.

For a week of small diameter drilling at € 1000 per day we reach € 7000, which is not very high, considering the ultimate goal of removing all fuel forever, if its price, with the additional installations, is that of a good boiler.
Even at 10 € per meter, 15000 € is not astronomical (10x10 = 100 holes at 15m every 1m for 1000m3).
Given the novelty, once developed, sold in series, the price could drop significantly.

An article talks about 170k € for 230m, but to pass a 55cm tube.

The price of € 730 per meter for very large diameters is to be compared to that of shallow open-air trenches with road repairs around € 200 + 30 = € 230 per meter for 40cm by taking a co-owned rainwater quote. that I have in front of me.
They intervene at this price for situations where they are the only ones, river, TGV, motorway to be cut !!

A US site that has used this principle for more than 30 years to heat the earth for the winter: Annualized Geo-Solar (AGS), annualized solar geothermal energy (GSA) on a new house:
http://greenershelter.org/
http://greenershelter.org/index.php?pg=3
A useful comparison of the different solutions:
http://greenershelter.org/index.php?pg=2

The basic elements of an AGS system consist of:

1. Any WELL-INSULATED (in the above-grade or shallow-earthed, planted portions) STRUCTURE, designed to minimize heat losses and gains, with a conductive floor that facilitates heat transfer, at least in heat-return zones.

2. Some ISOLATED HEAT SOURCE (typically air-based summer solar, although one could use another energy supply and / or transfer media.)

3. INSULATED TRANSFER DUCT / PIPE segments to carry the heated medium (air or whatever) from heat source to the dispersal zone earth beneath the house with minimum loss.

4. UN-INSULATED DEPOSIT DUCT / TUBE SEGMENTS imbedded in the dispersal zone, where heat is transferred to ...

5. ... An adequate mass of DRY EARTH for storage and for time-lagged transmission, before moving up through ....

6. ... the CONDUCTIVE FLOOR MATERIAL and radiating into the living spaces.

7. A CONTROL ON unwanted premature HEAT RETURN, either by the time required for it to travel through the VERTICAL DISTANCE between deposit site and the slab above, or by the HORIZONTAL DISTANCE between a deposit site directly beneath insulated areas of floor slab and the nearest un-insulated floor areas where one wants heat to conduct up through the floor. This latter approach is usually the easiest answer (no deep ditches / less diggable soil depth required); typically this means running the dispersal ducts / tubes under the insulated central portion of the floor, so the heat must travel out horizontally for 6 months (about 9'-10 ') before reaching perimeter uninsulated areas of the slab (the areas above which most of the heat loss through windows, doors and exposed walls also usually occurs.)

8. An AIR OUTLET OPTION - either a solar chimney (for a totally passive flow, where other factors make that feasible), an extraction fan (sometimes PV-powered), and dampered exhaust outlet, or return of the medium to the isolated heat source, for warming.

9. PERIMETER SUBGRADE MOISTURE-DIVERSION / INSULATION CAPE, extending from the structure's outside walls out to about 20'-24 'from the deposit tubes / ducts, to prevent heat from short-cutting back outside, instead of coming up through the floor. (This often actually means just a 6 'to 8' band of perimeter insulation, since most of that 20'- 24 'distance is actually under the house - a major cost savings and landscape benefit not enjoyed with PAHS 20' edge extensions.)

10. SIMPLE CONTROL SYSTEMS that regulate when the flow is activated and when all exhaust convection is blocked (to prevent the unwanted venting of precious earth-stored heat.)

11. A few SENSOR POINTS to monitor performance and, eventually, determine whether it's necessary to restrict the amount of summer charging, to prevent possible winter over-heating.

All this may sound more complex than PAHS, but it's actually less expensive, more controllable and allows far more design and construction flexibility. And with its potential to meet 100% of your winter heating needs, while keeping you toasty warm in winter and cool in summer, it offers tremendous future freedom and long-term savings on energy bills!

[dedeleco]

you always talk about time and distance of heat diffusion: but this figure is not what interests me! what proportion of the stored energy will be lost? whether it broadcast 1m or 10m does not really tell me

Answer given above:

In one day 250m or 20 boreholes at 12,5m or 10 over 25m under the whole garden, so in one to 5 days, we obtain the essential of the underground tubes to crisscross a volume of 10m per cube (1000m3) to be heated from summer to winter (on ground without circulation of underground water, which can be blocked by injecting underground product blocking pores and cracks).
In winter, with the thermal diffusion over 3m on the periphery the hot volume becomes 10 + 2x3 = 16m in the cube = approximately 2197m3 and therefore the temperature difference is reduced by 2,2 or by 13 + 40 ° C = 53 ° C in summer on 1000m3, we go to 13 + 40 / 2,2 = 31,1 ° C sufficient to heat without heat pump at 20 ° C, by air circulation on exchanger, like the heat pump, but without the heat pump, which is replaced by the heat of summer. !!
This heating from summer to winter becomes free in perpetuity, without changing or remaking the whole house.

The difference in volume earth water heat is not enormous, because the earth remains moist and the gain is not very significant.
But you have to see the price of a 200m3 tank (
http://www.jenni.ch/pdf/Artikel_DOMOTECH.pdf
, € 15000 for 10m3 in Switzerland not delivered to France and without the price of special foundations) while summer on winter you need 1000m3, an Olympic size swimming pool, for an old house, while the land is almost free in comparison !!
In summer solar collectors can be very inexpensive, at 30 € per m2, ineffective collectors in winter.
In my opinion the earth is much simpler, available, free, just to drill under his garden !!!
see :
http://greenershelter.org/index.php?pg=2

[chatelot16]

For a week of small diameter drilling at € 1000 per day we reach € 7000, which is not very high, considering the ultimate goal of removing all fuel forever, if its price, with the additional installations, is that of a good boiler.

the price of drilling is one thing, but there is also the price of pipes to pass in ... and the rest

but what interests me is how many kwh you can put in your 1000m2 of soil

and above all how long it will take to lose half of it

in addition it reminds me of something else: the capacity of the tank being fixed if the sensor surface is too small or if the summer is rotten, or if there is another problem, the temperature of the basement will not rise enough high and it will be useless

with a large tank there is no obligation to fill it completely: you can adapt its filling as needed: you may prefer to end the summer with a tank half full of very hot water rather than completely full of warm water

[chatelot16]

Answer given above:
In one day 250m or 20 boreholes at 12,5m or 10 over 25m under the whole garden, so in one to 5 days, we obtain the essential of the underground tubes to crisscross a volume of 10m per cube (1000m3) to be heated from summer to winter (on ground without circulation of underground water, which can be blocked by injecting underground product blocking pores and cracks).
In winter, with the thermal diffusion over 3m on the periphery the hot volume becomes 10 + 2x3 = 16m in the cube = approximately 2197m3 and therefore the temperature difference is reduced by 2,2 or by 13 + 40 ° C = 53 ° C in summer on 1000m3, we go to 13 + 40 / 2,2 = 31,1 ° C sufficient to heat without heat pump at 20 ° C, by air circulation on exchanger, like the heat pump, but without the heat pump, which is replaced by the heat of summer. !!
This heating summer to winter becomes free in perpetuity, without changing or remaking the whole house

for me a mass of soil at 31 ° is an empty tank: with the temperature drops in the drilling there is nothing left to heat anything: or you need a heat pump ...

so it will take even more than 1000m3 and have sufficient sensor surface to make them rise high enough in temperature: it seems to me completely measured for only heating

large simple sensor area only effective in summer + seasonal storage ... blah

there is more hope with a powerful sensor continuing to work on sunny days in winter + storage for one week

[chatelot16]

the energy loss from storage is not limited to what is lost between summer and winter

when the soil temperature has dropped to 30 ° I consider the accumulator as empty, but it will continue to drop to 10 ° average soil temperature

and the next summer you have to reheat everything to the maximum temperature

to be effective all winter long, the temperature should not drop too much so the loss of the following years cannot be calculated by the heating of the first 3 meters of earth: one would think that the loss of the following years will be lower than 'at the beginning: it looks more like a story of thermal resistance than diffusion

with a storage temperature that oscillates between 60 and 30 ° between summer and winter the temperature will be almost constant at 3 meter from the storage area, but this temperature will be higher than the normal soil temperature, and there will be a constant flow of waste heat: this waste heat must be calculated

[dedeleco]

Heat diffusion formulas which include thermal resistance as a limit case (read the references given in past posts), allow to calculate everything.
We can also simulate everything in a reduced storage model, on a reduced scale, as I explained and clearly visible in the equations. it's easier and more concrete in my opinion.

But if we slightly oversize the summer heating, given the low price of the summer solar collectors at 30 € per m2, by overheating, the heat lost by diffusion over several years will be low and recovered in the following years by a more earth hot.
From one year to the next, by heating the earth in summer, the winters will be warmer and warmer because the heat diffuses a little further with the n years, as square root (n), therefore more and more slow. It never returns to the average soil temperature of 13 ° C (10 ° C in very cold areas, but 13 ° C on the Maginot line), but the volume of soil above 13 ° C increases gradually, with a litter like rac (n) either in 4 years, 2 times further, and the loss over a weak year will be more and more small, if the winter cools less than the summer heats, by oversizing the summer solar collectors (easy at 30 € / m2, see Christophe, to have 30 to 40% more in summer than what the future winter demands).
This is why the earth allows a large inexpensive volume, which never a tank of water allows at a reasonable price (Olympic swimming pool!)
Everything is based on the diffusion with a length of penetration of the heat in curve of gauss on a range like square root of time.

for me a mass of soil at 31 ° is an empty tank: with the temperature drops in the drilling there is nothing left to heat anything: or you need a heat pump ...

A soil at 30 ° C at the end of winter is ideal for heating because a heat pump does not give more in its exchanger (good yield if T not high) and drilling in hot earth has no reason to cool, especially if it is isolated on the last meters.
Some would be happy to have a soil between 40 and 30 ° C throughout the winter and would not spit on it !!


Finally this site has been carrying out this method for 30 to 40 years !!
http://greenershelter.org/index.php?pg=3

large simple sensor area only effective in summer + seasonal storage ... blah

there is more hope with a powerful sensor continuing to work on sunny days in winter + storage for one week

Have you calculated the storage volume for one week for heating and not just domestic hot water?
If a typical old house, with a cold season of 26 weeks, you need 1000m3 / 26 = 38m3
The Swiss offer commercially and functionally, for hyper-insulated house with heating using only the sun 10 to 31m3 from 15000 to 30000 € with in addition transport and foundations (new house compulsory special) !!
Heizen nur mit Sonne - Energiezentrale für praktisch voll solar beheiztes Haus:
click on Saisonspeicher or seasonal tank (summer to winter)
http://www.jenni.ch/index.html?html/pro ... rtank1.htm
Everything is in German, and the choice translated into French is very very small !!