Need advice choice boiler logs or pads 50-70kw

[Rudy73]

Hello to you and thanks for this forum who has already helped me more than once.

I post my first message today because I have the impression of going around in the jungle of boilers and it's not for lack of not having searched enough on google ...

Here is my goal, to heat an old barn fitted out moderately insulated (but I work there) with a total surface of 500m2, there are many of the same family to share the building and there are also some studios which are given in hiring.

My second goal even if it is not a priority is to be able to be absent maximum 3-4 days without being obliged to refuel the boiler

My budget is not huge ... max 8000 € for log boiler and 15000 € for insert boiler it is sure that the ideal for me it will be a insert boiler but when I see the prices ... they tell me talked about some cheaper and very robust Polish or Austrian models but impossible to find them on the net.

Otherwise can be a semi-automatic log boiler or conventional log boiler with (very) large buffer tank (hydroaccumulation).

What will you advise me for a reasonable budget? Which dimensioning, power etc?

I specify that the boiler would only be used for heating.

Looking forward to reading you.

[Rudy73]

Nobody ?

[Gaston]

Nobody ?

I think that for these powers, we go out of the "particular" category.
One of the subscribers to this forum or a professional boiler to advise you
At first glance, I fear that your budget is too limited ... but I am not an expert on the issue.

In terms of sizing, it would be good if you already have an idea of ​​the heating consumption of your building ...

With a ladle, I will offer 200 kWh per day

[Christophe]

Well the individual or collective sizing, it doesn't change much if?

For power it is enough to be based on current consumption ... and to make some corrections related to the wood.

How is it heated?

I think you should not count on log heating for such a surface, unless you have someone part time to load the boiler ...

The budget also seems very low to me!

At first sight, we will be at least around 30 € for such an installation ...

[Rudy73]

Today there are 250 m2 habitable and inhabited, consumption of 3000 € of electric heating + 20-25 cubic meters of wood (2 stoves)

Indeed, I think that I am going to abandon the idea of ​​the log boiler and surely move towards a multi-fuel boiler.

I was thinking of investing in a crusher, I saw a used one around 3000-5000 € thermal capable of grinding up to 12 cms in diameter.
Since my father has 2ha of abandoned oak forest I thought that the investment could pay off quickly.

What do you think ?

For multi-fuel boilers, do you know of models capable of burning in a secondary log fire, it can always be useful ...

So far I have only found the biokompact, http://www.biokompakt.fr/crbst_7.html Do you know others and what do you think of this brand?

[Christophe]

If you have the possibility of making forest chips (shredded wood) then go for this solution, it is the most economical but you need a significant storage volume (and well ventilated).

Small () to the experts. On this video http://www.youtube.com/watch?v=VRNC7Pg52lo what is the use of lime added before combustion to straw briquettes?

[Gaston]

Well the individual or collective sizing, it doesn't change much if?

For sizing, no, but to advise specific models ...

Today there are 250 m2 habitable and inhabited, consumption of 3000 € of electric heating + 20-25 cubic meters of wood (2 stoves)

So approximately:
- 30000 kWh electric
- 50000 kWh of wood (2000 kWh per cubic meter)

On average, 40% of the annual heating is consumed in December and January.
Or 20% over 30 days or 720 hours.
This gives an average heating power over these two months of 22 kW.
Sizing at 50 kW does not seem exaggerated for the coldest periods.

For storage, 3 days at 22 kW, or 1584 kWh require approximately 35m3 of water (hot at 80 ° at the start and 40 ° at the end).
What a small pool ...

[Did67]

Agree with the above.

"Mixed fuels" is often a non-choice, then a source of annoyance! By dint of being specialized in nothing, your boiler will be a little wobbly in everything.

If you have room to store the platelets, the investment in a "top" platelet boiler will be worth it. With a self-built silo + a little old agricultural equipment to reform to "store", crush, transport, it will also be automated ...

You manage your 2 ha in rapid regrowth thicket (possibly by letting other species faster than oak take over: chestnut, acacia (finally Robinia false-acacia), birch, poplar ... depending on the ecological environment). ..

I do not have the data there, but would have to evaluate the natural growth to know if it is sustainable (it seems a little fair) to validate completely ...

You will one day find a good wood boiler not top but not too expensive, that you put in parallel for logs to burn, it would be a shame to grind (this degrades your energy balance).

[Ahmed]

Christophe asks:

what is the use of lime added before burning to straw briquettes?

Raising the melting point of straw ash to limit clinker formation, the main drawback of this kind of fuel (straw, wheat) ...
It clogs a fireplace in no time and forces frequent and painful cleaning.