Plukrijp built a mass heater

A brief history

1. A few years ago Gabriel introduced the idea of “rocket stoves” to Plukrijp&built one from 2 old gas cannisters&old stove pipes for our first (small) sauna.
2. Serge made a workshop weekend later on Plukrijp, building a 2^nd combustion stove with introduction of air from above (deom system) out of an old lpg-bottle, some vermiculite&some scrap metal
3. Nico, Davide & Régis&the “dirty dozen” of Plukrijp had loads of fun mixing clay (we had got free) with some yellow sand (dug up here) to fill in a wall space underneath the spiral staircase. We estimate it to weigh approximately 4 tons.
4. In it Serge embedded 12 m of 25 cm pipe (new=bought in the store around the corner) in 3 loops, connecting it to the chimney
5. Claudia decorated the wall, a real masterpiece of creative recycling&storytelling
6. We burned right through the 2 mm hull of this stove the next (very cold) winter, trying to heat our 11x11x3m workshop. Frank took this as a lesson not to build stoves with metal anymore&started looking around for alternatives
7. Luk had 19 big&very heavy 50x50x25 refractory tiles lying around in Herselt. He generously offered them to Plukrijp
8. Willem &Sebastian&a few others Plukrijpers nearly broke their back (&the suspension of the vw bus) bringing them here
9. Frank started looking around for plans to build a mass heater with 2^nd combustion chamber with these stones. A rocket stove was not a solution because of “no old lady available to put sticks in it day&night”. Together with Bram they expected vision, insight, books, tools, precision&experience to come to Plukrijp. Daily magic as we practice it here.
10. Bram was involved in most of the previous points&built a few rocket stoves for our caravans
11. Frédéric spent a “cold” (7-12°C) winter in the room above the stove&complained a lot about it. Willem always was happy with the same sleeping conditions.
12. Frank&Martine met Régis again at the Valériane fair sept 2013. he had started up his own business meanwhile, selling ready-made modal-2ndcombustion-refractory-cement-stoves for a reasonable price+building the stoves at people’s houses. F&M were charmed by the concept&decided to buy one from him for the room where we screen videos to replace the old wood-devouring stove there. Delivery date mid december 2013.
13. Régis sold us THE book on 2ndcombustion&finoven&… stoves. F&M were interested because Camilia, their eldest daughter had bought a poorly insulated house in the street.

14. Bram&F&M spent some time trying to draw a plan for the stove in the workshop. We had some ideas but we did not feel confident enough
15. Frank’s “bear-friend” Cyrille came along& drew the first draft of the plan. A man with vision&paws&courage ! Alas life took him along for his next adventure a week later. Good people, why do they all have such busy lives?
16. Diederik brought on the idea, simple but clearly unthinkable before, to take the spiral staircase out of the way. This had been keeping us from building the “Frank” way=straight.

Now finally there was enough room for serious building.

17. Gabriel(see 1.) came by for his yearly (please Gabriel, make it 2x/year) surprise visit to Plukrijp. “To see wether we had been doing nice work”. He is a bit our father-confessor, ecologically, socially, culturally, …..When we showed him our plans, he drew the first “real” one&gave us a week of his creative life energy, including new songs&dances
18. Martine’s birthday became a massive contact-dance demo thanks to him&Frédéric(biodanza)&Emmelie(our artist-in-residence)&Irina(god bless Ukraine for giving us such beatiful creatures!).
19. So the team started building. In 1 week’s time we put up a 5 (or more?) ton brick stove
20. Grayson learned how to weld(from Gabriel), cut metal(from Willem)&make cement(from Frank). Schooling fees=€ 0 !
21. Barrie started learning how to work with his hands, what an experience for him, learning he can do more with them than rolling cigarettes. That day was the first day of the rest of his life, if he wants to.
22. Frank&Gabriel found out that between planning&executing many unforeseen last-minute solutions were needed&found scrap material lying around&improvised a lot. They learned to think&act together, what an achievement ! Thanks Gabriel!
23. Bram came&saw that it was “a mess”, but promised to help with the doors next weekend.

He was of course involved in all the previous steps also.

Would we even have a workshop without Bram?

Thanks for your honesty, man!

24. Francesco patiently solved any small&bigger problem with precision, making us wonder whoever let him get out of Italy, a country in dire need of competent problem-solvers after their problem-creating former “presidente”. He wants to place the doors from an old stove Frank still had standing around on the front. This way, Plukrijp might have built a miracle stove in lees than ONE week!
25. We tried to light the stove too soon&got a lot of smoke. Wet cement gives off lots of white vapour too. So we let her rest for a week, meanwhile we made the lower chamber door fit better.
26. 2 weeks later we started her up again&lo&behold!: all went well. We quickly found out how to balance the incoming/outgoing gases&valves (see manual)

Building of a storage heating/inertial stove

The storage heating stove is a fireplace made of ceramics or natural stone. The energy or heat produced by the combustion of wood is absorbed by the whole structure of the stove. Thanks to the combustion of wood, the stove radiates the energy to the surroundings, accumulated through time in form of radiant heat, working as a well-balanced heat exchanger.

Besides having the usual combustion chamber, the structure of the stove allows smokes to flow through it, and after a long path they reach the pipe and exit.

Both are made of refractory fire-resistant material. This way, the heat is accumulated in the whole building structure of the stove, which gives heat to the surroundings almost exclusively through radiation.

Construction steps

1. Construction of the basement, the inner wall is covered by fire stones
2. Laying of the grill on which the wood will burn
3. Laying of the 1st level stones and inserting the supplementary entrances for air on the edges of the combustion chamber
4. Insertion of the second entrance for the air
5. Main combustion chamber.
6. As the main chamber is done, we reinforced the walls and we laid the roof of the combustion chamber, which will become the floor of the smokes’ chamber
7. Laying of stones for the smokes’ chamber
8. Laying of the vent pipe in order to compute the proper grade
9. Laying of the second stone wall and construction of a surface made of fire stones for cooking inside the smokes’
10. The heat and the smoke, lifting from the combustion chamber, flow through the superior chamber before reaching the vent pipe. This way the heat diffuses in the whole structure, which irradiates the heat in the surroundings. It’s then possible to use the superior (smoke) chamber to cook or dry anything
11. Laying of the secondary vent pipe
12. Construction of the valves for the main and secondary vent pipes
13. Laying of the superior door
14. Laying of the inferior door
15. Laying of an additional layer of bricks to increase the mass of the stove

Instruction manual

Lighting

1. Open the holes for the air nr. 1, 2 and 3.
2. Load the stove with wood in the door B and light the fire.
3. Open the door C (main air entrance) in order to let the air come in and favour the lighting.
4. If the draught of the vent pipe is not strong enough, either light a small fire or use a starter near the hole for the air nr. 1 in the door A in order to quickly heat up the vent pipe.
5. When the flame is burning well, close the door C.
6. Let the wood burn for 1 hour to heat the stove at the right temperature, and then close the hole for the air nr.1.
7. When the wood stops smoking, close the valves nr. 2 and 3.
8. Now the stove should start irradiating heat.

Conservation

The stove should be loaded about 2 or 3 times a day, according to the type of wood.

1. Open the valves nr. 1, 2 and 3.
2. Load the stove with wood in the door B.
3. Let the wood burn for one hour.
4. Close the valve nr. 1.
5. When the stove stops smoking, close valves nr. 2 and 3.

Further remarks

• During the heating phase, the side holes for the air directly entering in the second combustion chamber suck in cold air, while in the conservation phase they release hot air.
• Periodically, the ash should be removed through the door C.
• The metal plate over the second combustion chamber on the top of the stove can be used as cooking surface.
• It is possible to use the chamber behind the door A as an oven, dryer or to make smoked dishes.