Inter-seasonal solar thermal energy storage

[benn-]

after browsing the forum and others forum I did not find the info I was looking for on an idea I had.
I am looking to make a 100% autonomous solar thermal heating installation.
I will show you the system I thought of. First of all it is a BBC house equipped with a high efficiency double flow CMV. this is coupled to a Canadian well. The roof is equipped with thermal solar panels, the installation is the same as that of a combined solar system. The nuance is to create the thermal reserve under a second Canadian well (see if it requires doing it deeper, see insulating above to limit losses). this system would make it possible to further optimize the preheating of the air (why not install a bypass between the well at "normal" temperature and the one at boosted temperature so as not to exceed the desired temperature)
do you think this system would keep the heat from summer to winter?
solar panels would only have to adjust the temperature with a heating plate or radiator.
Thank you for your attention to this idea

[dedeleco]

Response on the basic principle between summer and winter, in a slightly different form, currently functional at http://www.dlsc.ca since 2007 and analyzed, discussed on econology strongly on
heating-insulation / heat-of-summer-in-the-winter-a-Drake-landing-solar-c-canada-t10828.html
Solar-thermal / heat storage de-sun-in-the-ground-t10173.html
medias / dedeleco-or-rather-drake-landing-solar-recompenses-t11299.html
renewable-energies / heat-pump-under-parking-t11188.html


The essential point is to make a Canadian well, deep enough and large enough so that the diffusion of heat over typically 3 to 6 m approximately between summer and winter, does not lose too much temperature between summer and winter, and gives back in winter the necessary heat.
A typical dimension of the volume of soil is therefore necessary for more or less cubic storage, clearly greater than 6 m.

It is necessary to measure the thermal diffusion and the thermal capacity of the earth used.
The insulating thickness can be reduced to 2m with alternating layers of earth and good insulator.

Many variations are possible respecting this basis.

[Obamot]

Hello and welcome Benn.

While you're at it, start with this topic:
heating-insulation / heating-solar-building-with-thermal-buffer-in-switzerland-t11285.html

It is the “zero emission” installation and zero heating costs, the most advanced and the simplest to implement at present (amha). => in a case like yours, I would study this possibility first.

And if you want to examine a thread where we have already redone the contradictory debate on the links that Dedelco advocates, and know why its solution cannot be adapted to all cases (it is also not zero emissions ) see here:
heating-insulation / storage-and-phase shift-geo-thermal-in-the-soil-t10470.html

(this is the most advanced synthetic thread, which leads us reasonably to the solution given in the link above => thermal balloon in a tank inside the construction).

It is the most economical and logical solution today.

Storage in the ground is not bad .... but ... (etc, I'll let you read!)

Depending on the region where you are, an additional heating with wood, may still be a good solution. Good reading!

[benn-]

I had read all these subjects but the problem is for example where to find a tank which resists heat at a reasonable price?
in the system I propose the additional cost compared to a conventional Canadian well is limited to the greatest depth of the trench and to the purchase of a few hundred meters of pipes for the reheating of the earth

[Christophe]

Are you sure you read them in detail?

Apparently, you are going to a storage solution in the ground ... how do you manage the infiltration of water that will necessarily cool your storage?

[dedeleco]

find a tank ..... at a reasonable price?

is the difficulty of the solution with large tank, which for interseason must be huge 400 to 600m3, which will not last longer than free land with holes over 1000m3 !!

So the simplest is the Canadian well, of large volume, as close to the cube as possible and more than 3m deep (or else isolated on the surface by 2m of earth and alternating insulators)) and preheated in summer by the sun on sensors, almost identical to a good Canadian well.
The heat exchange is better with water, but can also be air, or a mixture of the two.
Preheating in summer saves on heating costs, even if everything is not perfect and sometimes requires operating in classic mode.
A conventional Canadian well also has a problem of water moisture coming from the surface in winter which cools it, and therefore it is better to isolate it in surface and side humidity with waterproof plastic sheets, or injected cement.

[Christophe]

Now that dedeleco says it ... he will convince me ...

It is true that in the absence of flow (water table or sloping ground, with stream, as with us) by putting an "umbrella" under the ground, there is a strong chance that this will limit the flow! (the water rarely rises except in the event of a source ... it seems to me ??)

Under this umbrella: provide a safety margin of X m which would make “aqueous buffer zone” + Y m in “dry earth insulation zone” + Z m of thermal storage radius “useful zone” ...

It should be in the order of the possible ... but it makes earthwork ...

[minguinhirigue]

Hello Benn.

I had followed more than two years ago now the launch of the wire concerning the inter-seasonal storage with pebbles (overheated Canadian well with phase shift towards domestic spaces)

I continue to think that this is a useful technique for producing free heat for any building requiring deep foundations (editor's note over 3m).

But apart from this case and in particular for individual houses, I think today that simpler systems exist. A good passive house, with 4m² of correctly sized solar panels and a pico-cogeneration boiler as support, it is 80% free heating, and the rest at the top of what does today.

Not that we can't do better (95% free heating with efficient inter-seasonal storage), but in terms of economic and ecological compromise, I think it's more efficient if there is no a priori important earthworks to do.

I look with interest at your project, see if my intuition is wrong?

[dedeleco]

In winter, there is not much sun and on old houses it is very difficult to reduce heat losses enormously, to make it almost passive, this for a price much higher than that of small diameter holes in the ground under car parks, which disturb almost nothing so well designed, with simplistic summer solar thermal collectors on the roofs.

The only difficulty is to innovate, to carry out inexpensive drilling (or simple drilling robot) and to develop with a little creativity instead of saying that it is impossible while it works. www.dlsc.ca.

[Christophe]

Newer subject: solar-thermal / inter-seasonal-storage-of-solar-thermal-t14320.html and more complete ...