Twin Bio Luxury Fescue 12kW Pellet Stove Installation with 600-1000L Buffer for 88m2 Home

Hello to you,
I'm getting myself done for the central heating installation. in the installation, furnace twin bio luxury fescue 12 kW, which I would like to fasten with a heat buffer 600 to max 1000L.
I am afraid that the boiler will often light up to provide the right amount of energy. House with an area Usable 88m2, radiators + floor-standing in the bathroom and vestibule.
I am asking you to share your knowledge, does it make sense?
heat balance:
http://cieplowlasciwie.pl/wynik/38e2

tadiere wrote:

I am afraid that the boiler will often light up to provide the right amount of energy.

I share your concerns. The data provided show that the boiler will operate for only 10-15% of its rated power for most of the year - which either forces continuous work at a negligible power (which will be associated with low efficiency of combustion - if at all the modulation range for work with such a low power will allow) or with work with frequent cyclic switching of the boiler. The latter option is also an additional cost - because the lighter some electricity is pulling ...

Since you have a pellet boiler, this buffer is not a problem in itself - the pellet stove does not work in the so-called pellet boiler. sustaining (like the one for eco-pea coal), so there will be no fuel loss while waiting for the buffer to run out. When the water in the barrel comes to a halt, the stove will turn on and that's it - it will work with maximum power, which will certainly increase its efficiency and increase the cleanliness of combustion. In my opinion, this option is worth considering.

And what are you going to do to warm up the CWU? Also using a boiler? Do you plan to install solar panels or PV panels for heating CWU? In this case, the buffer will have an additional sense to apply it ...

Hello,
hot water also from the boiler, a separate boiler, min 200L for a family of 4. Buffer 0W
Can you suggest the correct installation diagram with the buffer?

tadiere wrote:

in the installation, furnace twin bio luxury fescue 12 kW

tadiere wrote:

House with an area usable 88m2

Who selected it for you?
Recently I installed a boiler at 120m2 with a capacity of 10kW and after heating the building turns on several times a day for 1 hour.
Buffer in this situation as much as possible. In total, the huge costs of such a boiler room will come out. Only I always think about the whole idea, service and costs and I am surprised that it is so difficult to convince people to cheaper, more convenient solutions.

andrzej lukaszewicz wrote:

Who selected it for you?

Probably the average Polish installer. On the other hand, a small consolation, because smaller boilers from 10 kW on the market, are not there anyway - and it's still too much for everything to work as it should.

andrzej lukaszewicz wrote:

I'm surprised people that it's so hard to convince them to cheaper, more convenient solutions.

Gas boiler + propane in the tank?

tadiere wrote:

Can you suggest the correct installation diagram with the buffer?

You have Kostrzewa's boiler and the first step is to look at their website and download their schematic with the buffer - here you have a link: SCHEME

The fescue's side, however, but the experience of forum members and their answers in the subject are very welcome, and give an interesting perspective on the matter.
The site of the boiler producer kalvis also has an interesting diagram with a buffer. It's just that producers with their bajerami and life and experience is a different story.
Question whether CWU should be heated from the buffer or from the power supply?

This fescue scheme is ok. A constant temperature return valve with a min. 60 deg insert, eg Esbe VTC or afriso ATV.
You do not write how the flooring connection looks like but I guess that with this size and loops in the bathroom and vestibule, you have it on one radiator manifold and OP loops controlled by RTL valves. If so, the length of the loop should not exceed 50 mb otherwise there may be a problem with flows. Valve on the outlet for 3d installation thermostatic x with a range of 35-60st eg Esbe VTA or afriso ATM
What to connect to CWU depends on whether you want to heat the boiler all year round. If so, it is worth connecting from the boiler circuit in order not to heat the buffer in the summer in order to charge the tank or in parallel from the boiler and buffer with shut-off valves it will be possible to switch.

tadiere wrote:

Question whether CWU should be heated from the buffer or from the power supply?

Still dependent on the boiler controller, because I met with such that the buffer was treated as a reservoir in the tank and then the controller did not support the pump loading the CWU.

Hello. Why do not you buy a 10 kW boiler? With a boiler that you propose, you have power modulations from 2.5 kW to 10 kW and you do not need a buffer, the boiler will adjust itself to the current demand. In addition, in such a system that you are interested in working installation and boiler that you plan to load the buffer 600 liters will take about 2-3 hours on the full boiler power, and at 1000 liters up to 5 hours. The buffer in your case will result in increased consumption of pellets and will unnecessarily complicate the installation of the boiler room. Instead of a buffer, use a hydraulic clutch, the rest of the boiler room installations should be done like a fescue diagram. Return protection valve buy at the temperature of 55 degrees, higher is unnecessary because on the pellet, the dew effect disappears at the temperature of 52 degrees.

ziomekorko wrote:

With a boiler that you propose, you have power modulations from 2.5 kW to 10 kW

Did you read that for the majority of the season the boiler will operate on about 1.5 kW of power - and this is well below the modulation range? And then what?

ziomekorko wrote:

Buffer in your case will cause increased consumption of pellets

And why is that?

Kostrzewa boasts of a twin bio luxury with an output of 8kW, I have not seen it on sale, and so the power range starts at 2.5 kW.

Xantix wrote:

andrzej lukaszewicz wrote:
I'm surprised people that it's so hard to convince them to cheaper, more convenient solutions.

Gas boiler + propane in the tank?

As you can see, you can count.
The PW heat pump reaches 80 meters and fits perfectly.

Xantix - no offense to the creators of the warmłowłasciwe.pl website (they have good intentions and I personally support it especially in the era of home plumbers who think that by doing several installations have already been super professionals) - I installed boiler installations in buildings where people suggested data from this site and there were spreads of + 30-50 percent anywhere. This is simply the case with universal calculators available on the internet. It's good that people believed in my experience and the designer with whom I work, because they avoided the cumbersome work of the boiler room and heating installations.
With such low boiler power, its construction and peculiarity of operation on pellet fuel, it takes a long time for the buffer to warm up to 60-65 degrees with a burner working at full power. If during the loading of the buffer, its partition takes place simultaneously, the buffer bake time is still growing and this results in increased pellet consumption. In such cases, it is better to use a hydraulic clutch because it favors faster heating of the installation (several hundred liters of water falls out of the installation) and consequently the building. The pellet boilers themselves ignite and quench depending on the producer and pellet from 30 seconds to max. 3 minutes. The necessity of long burning and maintaining the heat or fire on the burner disappears. The boiler is not enough to regulate the power of the burner, it is its working time and believe me it works well even on a small heat demand.

ziomekorko wrote:

If during the loading of the buffer, its partition takes place simultaneously, the buffer bake time is still growing and this results in increased pellet consumption. In such cases, it is better to use a hydraulic clutch because it favors faster heating of the installation (several hundred liters of water falls out of the installation) and consequently the building. .

How does this installation look like in exchange for a 4d valve - it is a hydraulic hatch?

ziomekorko wrote:
If during the loading of the buffer, its partition takes place simultaneously, the buffer bake time is still growing and this results in increased pellet consumption. In such cases, it is better to use a hydraulic clutch because it favors faster heating of the installation (several hundred liters of water falls out of the installation) and consequently the building.

And what is the buffer in the sense of a hydraulic ?: I have a huge clutch!
Burning has no right to increase, because why? The water is received from the boiler on a regular basis through a buffer like in a clutch, when there is no reception heats up the buffer and that's it. Losses that may occur are of the type of parking in poorly insulated buffer, but will be comparable to the costs of firing up and starting the boiler.
I do not see too much sense in assembling a buffer with a tiny boiler at any price, because the idea of a buffer is closely related to a large and even large boiler and allows you to use its optimal combustion conditions. Here, in a pellet boiler, where a firing-up system is used, the buffer is another costly, but not indispensable constitution in the boiler room.
It also enforces an enlarged expansion vessel or diaphragm.

Added after 1 [minutes]:

tadiere wrote:

How does this installation look like in exchange for a 4d valve - it is a hydraulic hatch?

The installation looks the same as with the buffer from the given scheme - the buffer is also a larger one.
If you opt out of the buffer, the clutch is not necessary. If the installation looks like I suspect and described in post # 9 (radiators with thermostats and floor-standing on RTLach), then only one pump with the mentioned 3d valve is enough to protect the return.

Thank you for your help

Hello, I will add my opinions on the buffer working with the pellet stove, so I have a Defro Alfa 12kw stove + 1000 liter buffer + 200 liter Viseman boiler, the stove is working at maximum, the buffer will heat up to a temperature of 75 degrees in 5 hours-plus 10 degrees outside, the stove fires once every 28 hours temperature in the apartment +22 - house 136 square meters insulated 10cm polystyrene + 24cm ytong ceiling insulation 25cm mineral wool 0.035 lambda ,,, 7-8 hours at 0 - (-10) degrees outside and fires once every 19-23 hours, when the temperature at the top of the buffer reaches 45 degrees, the stove will fire up automatically, burning about 13-20 kg a day, I am very happy ,,, advantages ,,, the stove warmed up, non-stop heat at home and the floor heating works 24 hours , I save the heater for infrequent firing up, the furnace's hearth is very clean, and Nobody will tell me that a buffer is not needed for a pellet stove ,,, I have a different opinion. Kisses

volkswagenseat wrote:

Well, I have a Defro Alfa 12kw stove + 1000 liter buffer

Well, you have a boiler with a capacity of more than twice as much as your building needs at -20 degrees, and on average in the season it is 3 times too big and here the buffer makes sense. In general, the buffer stabilizes the operation of any solid fuel boiler and reduces the amount of ignitions that are "expensive" with pellets.

Hello, I have a SAS 17KW pellet stove and a new installation with a heat buffer of 500 liters from hot water from a coil, a one-story house of 200 m2 of flooring only, 20 cm insulated polystyrene, 15 cm styrofoam ceiling, 20 to 40 cm wool roof. I only heat the ground floor. The furnace loads the buffer about 5 ha, then it stands only about 3 hours. The buffer is discharged very quickly through the floor heating. We don't live yet, so we don't use hot water. I wonder what is wrong because I am not satisfied with the use of a buffer here because landing it when the house is "not warmed up" can take 8-10 hours.... And it's cold at home anyway. Compared to the installation without a buffer, it works worse for me. Will the furnace be too small or the wrong buffer selected?

vauxchall wrote:

I wonder what is wrong because I am not satisfied with the use of a buffer here because landing it when the house is "not warmed up" can take 8-10 hours.... And it's cold at home anyway

Because the house is not warmed up and whether with or without a buffer, it needs a huge amount of energy to heat up from 10 to 22 degrees. The presence of a buffer in such a situation does not matter, because the entire heat of the boiler is immediately "stripped" on the building. The buffer will be perfect after heating the building, especially in transition periods, with temperatures well above zero.
The question arises to what temperature do you heat the buffer? 500 l is a small capacity, you can store only 23kWh of energy in it by heating it from 30 to 70 degrees for 1.5h with 17kW power.