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Post by milegas on Nov 5, 2021 10:43:32 GMT -8
Hi guys, I'm new here and have a question.
Can i make RMH like two blind benches as described in batchrocket.eu but my house is configured in a way that i must pass through walls on both sides to make benches in two rooms.
The question is can i connect benches with the bell by two pipes of wich one goes to the top and other to the bottom of each bench? Each pipe would not be longer than 1m.
Thank you very much in advance.
Cheers from Serbia!
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Post by peterberg on Nov 5, 2021 12:19:18 GMT -8
Just an educated guess here, but I think it won't work this way. The benches as built in North Carolina were completely open to the main bell to ensure proper streaming of the gases. Moreover, the layering of the gases in and out won't stay the same during the burn. In other words, the hot gases takes nore space than the cold ones, at least initially. But as the burn commences, the temperature difference between incoming and outcoming gases will become smaller.
Maybe you have to make a choice, just one longer bench through one wall. In order to have it work flawlessly, such a bench shouldn't have bends in it, just straight.
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Post by milegas on Nov 6, 2021 2:11:45 GMT -8
Thank you for your quick reply. Then i should give up thinking about this design. Maybe if i build a straight bell without benches and make top of the bell two layered with space between and use a fan to blow hot air to two benches and into two rooms? Or i could find magnesite pieces that form tube, they are used in TA electric heaters and form spiral tube. Or a cast iron top in the same system for better heat transfer?
Thanks
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Post by fiedia on Nov 6, 2021 7:11:25 GMT -8
I do not know if anybody built such set up yet (I mean heating two rooms with one RMH and one bell in an adjacent room).
I am working on this with interesting results. The second bell was warming the adjacent room quite well when fed with very hot gases see here. But when i connected the second bell to the bottom of my RMH bell, gasses where too cold to warm it up see here.
I am now building a bigger RMH with pipes both on bottom and top of the bell. As Peterberg wrote, the balance between bells will be quite tricky to achieve.
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Post by satamax on Nov 6, 2021 22:41:59 GMT -8
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Post by satamax on Nov 6, 2021 22:51:30 GMT -8
Hi guys, I'm new here and have a question. Can i make RMH like two blind benches as described in batchrocket.eu but my house is configured in a way that i must pass through walls on both sides to make benches in two rooms. The question is can i connect benches with the bell by two pipes of wich one goes to the top and other to the bottom of each bench? Each pipe would not be longer than 1m. Thank you very much in advance. Cheers from Serbia! Milegas, peter has said, blind benches are tricky. What i would do is use full vertical bells. Instead of benches. Or just wall heating. What i understand, you have a small room with another room on each side. If small enough, span the bell in the three rooms. Breaking the walls, as in Radek's stove above. Ths you could find interesting too www.heatkit.com/research/2009/lopez-rocket.htmA few pictures and a drawing of the room's arrangement could be interesting. We might see some solution that you haven't thought of. |
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Post by milegas on Nov 6, 2021 23:25:52 GMT -8
Yes, i have small room between two rooms. Small room is about 2m wide. The walls are brick made 25 cm wide. Wandering, could i span the bell and use existing walls as bell walls. The doors to side rooms are close to the heater and are almost constantly open. I know that its problematic but i really dont like the idea of braking walls it would be a major construction project since those are carrying walls.
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Post by satamax on Nov 7, 2021 14:10:00 GMT -8
Well, i was thinking it was the kind of implementation you would have. That's a kind of locker room entrance? A bit like in Russian homes, with bedroom on one side and kitchen on the other? Anyway, in that case, i think i would try an "arch" type of rocket. You make a burn unit in the center. Heat riser, and batch. Solid. Above you have a heavy firebricks chamber, with two insulated horizontal tubes, which go to each wall. You make the walls like in the lopez labs link www.heatkit.com/research/2009/lopez-rocket.htmYou make two small pipes or benches going from the walls, to behind the burn unit, and into the chimney. See what i mean? Imagine something like this with the burn unit in the middle.  |
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Post by fiedia on Nov 8, 2021 7:19:26 GMT -8
Satamax, you just described a very good solution. I mean injecting hot gases from the top of the heat riser inside the top of two bells on each side of the batchbox room (not building a huge cube at the top of the Champs Elysees). The heat from the burning chamber should bring enough heat for the middle room and most of the heat carried by the smoke would go into the two adjacent rooms.
Now regarding the shape of the bells, I would make them wider than taller. My experience is that most of the heat exchange takes place at in the top of the bell. In other words, it is better to have a long bell than a tall one.
Standard design rule is to leave at least 30cm between bell ceiling and hot gas entry. Combining this with SIA and room width should give precise guide lines for the bell design.
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Post by milegas on Nov 8, 2021 9:41:47 GMT -8
That is the kind of solution i was thinking about. Only i was wondering if i could make somekind of heat exchanger in a form of metal tubes above the riser and inside the bell, directly over max heat and a fan that will force heat through the tubes and into the rooms. Of course the heat would go to thermal mass in the room and then out of the open end. I could cast very nice looking massive radiators for the rooms. Do yoy think i could achieve satisfactory air temp to heat up the radiators for the rooms?
Another thing in this setup i think that batch build would give too much heat at once. Maybe simple j rocket would provide enough heat but for a longer period for the room radiators to heat up.
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Post by fiedia on Nov 8, 2021 13:59:24 GMT -8
After some prototypes, my understanding is that these bells do not work like usual heat exchangers. Hot gases stacked on the top of the bell will warm up the whole mass. Looks like the heat exchange thanks to flowing hot gases through pipes is less efficient here.
You may try to pump the heat of your central bell with pipes and fans. I guess you think of a secondary air path as for usual chimney insert. I do not know if anybody did such set up with success. keep in mind that temperatures above the HR can reach 500°C and above.
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Post by satamax on Nov 8, 2021 18:54:28 GMT -8
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Post by satamax on Nov 8, 2021 19:11:30 GMT -8
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Post by milegas on Nov 9, 2021 8:53:05 GMT -8
Well, you think that it could work if i build one main bell and two smaller that are connected top and bottom to main by say 200mm tubes.
No need for vetilators.
I would build side bells about the same height as the main but narrower and longer. That would be visually perfect. And my wife wouldn't throw me out of the house together with my RMH 😂😂😂.
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Post by fiedia on Nov 10, 2021 4:10:45 GMT -8
It is also what I am working on right now with two bells: two pipes 200mm on top and bottom to link the bells.
The center bell would not need to be that big since the firebox is the main heat source. If you want to balance heat between the bells, side bells have to be bigger than the central one.
It is much better to have a gap of 30cm between incoming pipes and bell ceiling. Your side bell ceiling should be higher than the top pipes.
If you build a tall bell, the lower half of the bell will be useless. It is better to build it larger than taller.
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