Solar passage

[falcon1208]

Hello,

Would anyone have any ideas regarding the following question:

I live in a house of 100 m² habitable with underfloor heating in Brittany. Altherma Daikin air-water heat pump,
who is now nine, is down and I do not want to fix it. I have a fireplace on the ground floor, she
served me the last two winters to warm me up. I powered directly into electricity, without going through the boiler,
his hot water tank, so I could have hot water too.

I would now go to solar (use of the heated floor) with booster using the chimney regarding heating
and electric booster for domestic hot water.

How to proceed ? Who to talk to? What helps the state are possible?

Thank you in advance for any help.

[Did67]

The sun has a disadvantage for heating: it is not very present when it is cold (short days, low angle of incidence and sometimes, even if I know it never rains in Brittany, overcast!).

It is therefore quite expensive for little "yield".

You're lucky to have a good system: the floor heating, which has inertia.

Rather than a costly and insufficient solar system, I would suggest to you:

a) to put the money in the insulation (outside), to decrease the consumption and to reinforce the thermal inertia of the house (the interior insulation will have the opposite effect: to decrease the thermal inertia)

b) to couple this to a "hydro" stove (part of the heat produced is sent to a water circuit, that of your underfloor heating): log stove (with restrictions - you have to light, recharge, etc.). ..) or pellet stove (fully automated, except refill of pellets) ...

c) the solar is better for a water heater, because it is also necessary hot water in summer, when the sun is abundant; we can therefore cover about 50% of the needs; there are double coil balloons, which allows to couple them with panels AND a boiler (or hydro stove) for the supplement or the days without sun ...

This is obviously only an opinion.

[Adrien (ex-nico239)]

a) put the money in the insulation

For having frequented different types of habitat (walls of 60cm old and new house) we became followers of ISOLATION.

We heat 150m2 (plain plied) with a small wood stove of the most classic 900m altitude: cons 2017-2018 5 stere oaks which is not much.

MAIS

The house is well insulated (we bought it as is) winter and summer (do not forget also the insulation against ... heat)

Since that experience, I have to admit that the power of good insulation has stuck me a bit, which does not prevent me from looking for economic or ecological energies.

However, I do not know the cost comparisons of an insulation (all over) to add to an existing house versus a new solar installation or other.

But it seems to me that starting with insulation is the ba-ba ...

[Did67]

like summer (do not forget the insulation against ... heat)

Absolutely!

And last but not least: the investment in insulation "stays" in the house, which increases in value. And more and more with energy rankings. While heating is an investment / consumption: an old heater risks breakdown and is not "worth" much! And this is true even for solar, even if it is a little less so.

[falcon1208]

Hello,

Insulation Question this house was built in 2009 and is at the standard RT 2005.

[Did67]

It's good. It is not a "colander". But it is still average! The standard was not so severe at the time ... It is 110 kWh / m² and per year in the west. Classification C. The RT2012 is 50. Classification A.

Inner insulation (ITI), I guess, alas ??? [Because it cuts thermal inertia; thermal inertia is in walls and slabs; if ITI, the walls are behind the insulation, outside; they do not participate in the inertia!]

That said, in fact, it makes it less relevant to think about insulation first ! You have the rest of our remarks!

[falcon1208]

Yes, the insulation is interior. But I thought, maybe a little naively, that I could increase the thermal inertia by using a heat reservoir (for example a water tank) and, if it lacks the energy to fill the hollow moments sunlight issue, increase the number of solar thermal panels.

I can, at first sight at least (...), increase the inertia and / or the power received. Why deprive yourself?

[Did67]

Yes quite. Depending on the space available.

Normally, we put the stamps outside the house "box": in the garage, cellar, etc ...

Because the more you raise the temperature of your buffer, and the less the efficiency of the panels is good ... It is easy to heat water from 20 to 25 ° with soliare. Much less 60 to 70 °, even if it is, on paper, the same number of calories! So you end up with 5 000 buffers l, to store at quite low temperatures and to heat with water at 30 or 35 ° (it depends on the density of your coils and outside temperatures). If you have room, no problem, you have better stamp as much as possible. Within reasonable limits.

You also need regulations that handle this: 3 mechanized track valve, control box / programming ... Even if the heated floors, thanks to their inertia, give you the opportunity to juggle a little. And that they smooth some temperatures ...

Because, except to give a damn about it, this poses a question of "profitability": very quickly, the additional cost of this equipment (panels and buffer tanks), which are used less and less (they are only useful for situations of increasingly extreme - extreme cold and long period of absence of sunlight), is never recoverable, even over 100 years!

To caricature: in summer you can heat with 0 panels and a buffer of 0 liters! In the offseason, with some panels and a few hundred liters you do not care. And the more the conditions become difficult, and the more you have to increase one and the other, for fewer and fewer days!

[falcon1208]

I was looking at what is called "direct solar floor". It's a simple system. Solar thermal collectors send the coolant directly into the floor, using a circulator or even, it should be seen, a thermosiphon if it is possible to place the collectors under the heated floor.

Would it suffice to place in series with the heated floor and therefore the sensors a tank (homemade if necessary ...)?

In this case the cost seems quite small.

[Did67]

Yes, it exists.

But it is better to have thick floors, massive ... Which then buffer ... The modern achievements of PC (heated floors) are rather in rather thin screeds (about ten cm max).

It is a way to bring back, with a dispersion in the hours which follow, the calories when there is sun. It is therefore more to be seen as an additional heating, aiming to "lighten" the balance sheet of a real heating system. Except special climatic conditions.

The only buffer is the slab! On days when the sun does not shine or only partially shines, contributions are zero or low. No way to "store" the calories collected the day before when the weather was fine and perhaps the need for heating was low (the house also receiving more or less calories through the bay windows, if it is ever so well designed) .

When you immerse yourself in a rapid thermal balance of a "fairly normal" house in a "very local" climate, you will see that this can only represent part of the thermal balance.

As for the thermosiphon: when the height difference is small, and the "pressure drops" (the friction of the liquid in the pipes, taking into account the connections, elbows, lengths) important, efficiency is not guaranteed. In principle, this is calculated.