Custom 6mm Sheet Metal Buffer Heat Accumulator for 30KW Wood-Fired Boiler in Basement

Question

Due to the costs of factory-made devices for heat accumulation, and the problem with bringing in a ready-made device, I am thinking of having such a buffer welded out of 6mm sheet metal. I am limited by the width of the cellar door of 80 cm, so I decided to make two elements with dimensions of 2...

adam0369 · Answer

An interesting idea to store heat, but the very idea of storage is associated with losses, but this colleague probably counts. As for my suggestions: the tank can be welded from a thinner sheet (e.g. 2 mm) and galvanized or, as a colleague suggests, from 6 mm sheet and left black. As for the structure inside, I would not finish the furnace return pipes and receivers at the same height, and I would even put a partition between them at the same power supply. Sealing compound can be used to seal the flange (it is purchased in the form of silicone and applied to the joints before screwing). It is mandatory to insulate well, you can use wool but polyurethane foam is better, after complete assembly, wrap the buffer with a thin galvanized sheet, leaving around 5 - 8 cm of space and fill it thoroughly with foam. You should also consider disconnecting the stove from the buffer when the stove is no longer burning so that it does not become a receiver, a solenoid valve on the return and a thermostat that would turn off the pump at the stove would be enough. That's all my suggestions, cheers

wawrzeczko_t · Answer

Galvanized elements are not used in central heating installations

I suggest not to combine only if you do - connect 2 or 3 smaller buffer tanks in parallel (a 300 l buffer has a diameter of about 75 cm). The advantages are: warranty, checked tightness, original insulation, coat, etc ... www.elektromet.pl www.pomex.pl

mroziuu · Answer

Does it make more sense to use such buffers connected to what without any coils? Are there any tables, converters or something that could be used in the decision?

wawrzeczko_t · Answer

I don't know if it makes sense. It depends on the whole plumbing scheme of your house.

xrafaladam · Answer

I have open installations at home, it works by gravity, but there is also a pump. Copper pipes fi 20 on risers and fi 15 for radiators. There are about 220 liters in the installation, including a large share of the stove and boiler jacket. Cast iron radiators. Domestic water from a 120 liter boiler with a jacket. The top of the overflow vessel will be approx
6 meters above the bottom of the buffer.
As for the buffer, maybe I will actually add a coil for hot water under the "ceiling" of the buffer and maybe a second one at the floor for solar, because if I twist it and insulate it, it will be a pity to open it again, especially since the lid can weigh 300 - 400 kg.

So far I've imagined it something like this:

xuzi · Answer

I recommend especially

xrafaladam · Answer

The address of this page has changed because they had some reorganization of the page in Murator, but in fact the topic of the buffer is described there exhaustively. Thanks for the info.

krzysztof64 · Answer

Please judge whether a 60-litre toddler made of an air cylinder from a truck, placed in a 1000-litre mother heated to about 65 - 70 degrees Celsius is enough to take a bath in a bathtub?

wnoto · Answer

But such a 300 l tank is PLN 1,500. By betting 2-3 items, we have almost PLN 5,000. In my opinion, it's expensive and that's why many people think about self-made.

xrafaladam · Answer

Coming back to the topic from two years ago, instead of welding a square in the basement, I decided to buy a 1700 liter scrap tank. I had a good welder cut it into 3 pieces and weld the legs and flanges. I also showed where to weld what muffs. I did the rest myself

)
It's not fully functional yet, but it's working.

there are no photos after thermal insulation and I don't have a decent automatic control yet, but I already know that the buffer is a bull's eye

)
I wonder how many days in the summer I will have enough hot water after lighting the fire once.

mirrzo · Answer

Quite a hodgepodge. And it works?

xrafaladam · Answer

Of course he works
has not yet reached full functionality because it does not yet have a decent control and is tinkering with automatic valve actuators. For now, it controls the valves manually, but everything works as it should.

)

mirrzo · Answer

I wonder how you bleed the system this node with the red pump. What are these PEXs coming out of the buffer for? What is this cross made of copper pipes at the bottom of the tank for?

xrafaladam · Answer

From the red pump, the system is vented at the radiators, i.e. from the pump, the air flows gravitationally to one of the radiator vents.

As for the pexes from the buffer, they lead hot water from the upper coil of the buffer to taps, washbasins, etc., the pex connects to the pex leading from the boiler, which is the source of hot water before the buffer started. Because the whole project is an experiment for me, I left the boiler as a reserve DHW tank, working by gravity with the furnace (for a rainy day, i.e. buffer failure or long-term power failure)

The crosses at the bottom of the tank (also at the top) are the frame of the coils. It is known that copper elements cannot be in direct contact with steel elements (electrolytic corrosion or something similar), so I screwed the copper frame, of course, through rubber washers to carry the weight of the coils.

The link given above by "mroziuu" leads to an extremely extensive thread on the murator forum about heat buffers, the topic has already hundreds of pages, so it is difficult to quickly get information from it. About a year and a half ago I read the whole thing and I have to say that I implemented a lot of things given on this forum when building my buffer.

mirrzo · Answer

That is, part on the pump, and the rest on the radiators In open systems, there is a constant probability of air bubbles forming, so the pump can run with air in it. You should rework it so that everything self-vents, above the pump. And you insulated the bolts too, and the water too? Will these crosses bear the coil without bending and resting on the bottom? check after a season or two.

xrafaladam · Answer

I think you misunderstood me with the vent. Going from the pump, there is a gravitational path of air bubbles to the installations where there is an automatic air vent at each radiator. So everything above the pump is self-bleeding.

As for the screws holding the copper crosses, I put a layer of silicone on the screws (where they could touch the copper elements sideways).

As for "isolating the water", I understand that it is a mockery. I do not know the exact name of the undesirable phenomenon, but I am sure that direct contact between copper and steel elements in such systems should not be allowed. So this kind of foresight is probably not a mistake. If not, I'd appreciate you letting me know.

The mechanical strength of the crosses seems to me sufficient, and as for the control, the problem is to check anything inside the tank, unless I find a gooseneck camera and let it through one of the holes. The mountain itself weighs about 150kg-200kg. So I hope I won't have to open it soon.

mirrzo · Answer

How about the pump? Plastic hoses would be better You should provide for an inspection window, because over time, a lot of stuff accumulates at the bottom of the hopper

xrafaladam · Answer

The pump is vented the other way, i.e. at the top of the buffer, there is one automatic vent and one manual vent, ultimately pulled out on PEX beyond the insulation. I can manage without the inspection window. I don't think it will be that bad. As a last resort, I will take a day's time, ask someone for help and remove the top cover. After all, if I managed to put it on, I can take it off and then I can even go inside with the welder. And as for the plastic hoses, the ones used by NASA would be even better, but I couldn't find a link to their online store )

1tropek · Answer

Cool. Unnecessary malice towards the person trying to help you. The whole structure amazes me. There is an idea, there is knowledge, there is motivation, there is implementation. My entry is not ironic, I actually admire the contractor, the implementer of this idea. If I can suggest something - replace these galvanized fittings with black ones and add some inhibitor to the boiler water. Fingers crossed.

xrafaladam · Answer

I'm wondering if it's worth replacing these galvanized fittings, or boiler scale won't do the trick?
I hope that it can last 20-30 years and then we will probably all warm ourselves with electricity or return to the caves.

With this igielite, "mirzo" was probably right, but I think silicone will also do its job. I hope my friend wasn't offended

)

All in all, it was on this forum that I started the whole adventure with the buffer and so I thought that I would write what the case ended up with and it's too late for major changes. Someday you have to stop improving and start using it and it took me almost two years to do it in installments.

Now I'm struggling with the controls and actuators closing the valves.

The annoying thing is that the heat escapes me gravitationally from the buffer, even though I reworked the connections so that they were U-shaped, but it did not solve the problem. Then the hot water escapes to the radiators. I was wondering if it makes sense to put non-return valves behind the pumps, such as those used in drinking water, so that it does not return, but I am concerned whether it will somehow significantly reduce the efficiency of the pumps and whether there will be no problem with venting (the pump may not push the valve without water, and not until it pushes the valve to release the air). As a last resort, I will do some solution with electrically closed valves, but the return ones may solve the problem. What do you think?

1tropek · Answer

In my idea I used a used Vaillant three-way valve. The one with 1 connectors. Controlled 220V - if you supply voltage, it releases heat from the buffer, without voltage - closes the outlet. Regards. ps. As for the bottom support. Three plastic tubes (legs), properly cut out, distancing the lower coils. I didn't invent it - that's how they do it in the factory ones.

mirrzo · Answer

I still don't understand something here. How is it possible, since the pump and pressure gauge are the highest points in this part of the installation.

1tropek · Answer

Assuming for granted that the can is upright. :D The upper pump is in series with the lower one? In this configuration it milks the buffer.

xrafaladam · Answer

The photo is quite unfortunate, this is a thermometer clipped on a tube. Above this place, everything spreads by gravity to the installation. (behind this insulated pipe you can see a thicker black one) As for connecting the pumps, the connection visible in the picture should ultimately be closed. If the buffer valves are opened and closed, the installation returns to the state it was in before the buffer was connected. The original idea was that the black pump pumped only to the buffer, while the red pump from the buffer to the radiators. The connection shown in the picture between them should be closed. But now I think it would be a bit of a waste, because when the stove was burning and wanted to heat the house at the same time, two pumps would run together unnecessarily. Ultimately, I want to give a 3-way valve behind the black pump and then the controller would decide whether to release heat from the black pump to the house or to the buffer. The red pump would turn on only when the furnace is not on fire and you would like to run hot water from the buffer to the radiators. I'll try to take better pictures tonight and draw a diagram.

kidu22 · Answer

Typical DIY. I like the boiler exit resized to 1/2 inch. And these pumps. A 3-way valve and thermostatic timer control would be useful.

Bogdanbenek · Answer

3\4 inch there I see or 1 inch and the pump has a half screw connection for 1 inch I don't see 1\2 inch in this photo

xrafaladam · Answer

all connections are 1'', while the outlet from the furnace with a differential valve (gravity) is 6/4

zbyszekkr · Answer

Hello. How did you make these beautiful collars?

Custom 6mm Sheet Metal Buffer Heat Accumulator for 30KW Wood-Fired Boiler in Basement

Post #1

Post #2

Post #3

Post #4

Post #5

Post #6

Post #7

Post #8

Post #9

Post #10

Post #11

Post #12

Post #13

Post #14

Post #15

Post #16

Post #17

Post #18

Post #19

Post #20

Post #21

Post #22

Post #23

Post #24

Post #25

Post #26

Post #27

Post #28

Post #29

Post #30

Topic summary