Lot of questions for a rocket plan with cooking and oven

[vire7777]

Helllllllo everyone

First thanks for accepting me here and for your time and patience if i m asking questions which could look stupid

I have to say i m very fascinated with all these things and i m searching for a new way to change my actual cooking station
I found these rocket stove very interesting and wanted to explore
So i made many researches and finally i made a plan to change my actual cooking station but also to add a system of heating my house after it

Here is the idea (system is in meters)
drive.google.com/drive/folders/1IR_0dfa6ISSbmrkGsdzqdj_Dt569-OcW?usp=sharing

Now here are all my questions
Most of them come from the case that i don t find real plans nowhere with measures etc...
The fact is, i love to know and plan before making and seeing it s not working hahahah
There is a lot of schemes about rocket stoves but nowhere i found actual real temperatures either
Sooooo...

1) Opening of the wood box
I used 20cm2 for putting wood. i feel i can put some good big wood parts like this which can burn for long
Do you feel that s enough or too big ?

2) Air opening
As you can see on the upper part, i was thinking to put a door for air passage that i could close or not.
i don t see it in all rocket stove plans. Is it useful ?

3) Tube opening
I decided to use 20cm2 for the tubes (all of them, even for the wood)
Does it seems good enough ? Too big ? Too small ?

4) Temperature on thermal mass (end tube) 
So what is the temperature to expect (more or less) on the thermal mass ? I think 140 right ?
I plan to have a tube of 6 meter long running into my house before going to the chimney
Would it be enough to heat the house ?

5) Length of the J
On my plan, i made a J length of 1.5m (0.6m + 0.9m up)
Is that enough to burn the gazes well ? 

6) Temperature end of J
What temperature could i expect at the end of the J (for the first cooking part) ?
Around 350 ?

7) Cleaning
Rarely i see where are the opening for cleaning the ashes. Because let s be honest, there ll be ashes
But where ? I would say in the J and the oven part, but what about the thermal mass tube ? 
Should i make also some openings there ?

8) Oven
I was thinking i could use a refractory bricks oven instead of a metal
In that case i would have to change my plans to make the cooking station bigger. Not only 1.1m but more 1.3m long
The oven then would keep the heat for long even without fire, right ?

That s all for beginning
Thanks a lot for your helps

[karelpm]

Hi

I read this post when searching for answers to similar questions. I don't want to start a new threat and would like to add my questions to yours.

I plan on building a new house and want to incorporate a rocket stove in the design for cooking, baking and water heating. My idea is to place this centrally in my house in a shared kitchen/dining area, underneath the stairs and landing to the second story. Heating is of secondary concern because I live in South Africa in a climate where the winter temperatures seldom drop below freezing.

I first concidered copying Matt Walker's riserless core in a 1 stove do it all setup, but could not find enough information online to properly size it, and I don't want to pay for plans during the planning stage.

The information that I found on the website batchrocket.eu by Peter van den Berg answered almost all of my questions regarding system sizing and I have since decided on having a fire for each different purpose.

Cooking.

I've decided not to use a rocket stove, but to build what we in South Africa call a Built-in-braai. It is an open fire with a grid with a straight chimney, no bell or anything complicated. Ready built units are available by companies such as Megamaster and sold by hardware stores and building suppliers. I have built these before and it will serve my needs.

Baking.

I plan on building a 6 inch Batch box inside a bell. I have no experience with these, and they are not common in my area.
The bell will be 900mm deep, 600mm wide and 1600mm high on the inside, which should give me the internal area of around 5,3m² suggested.
I plan to repurpose an old eyelevel oven with insulated door as a white oven or to custom build my own.
I want to use brick for the bell to store heat for the oven, and will have a flue bypass to be able to regulate the oven temperature.
The questions that I do not find answers for online are
1. At what height should I place the white oven inside the bell for Optimal temperature and heat transfer?
2. A distance of at least 30cm from the top of the riser to the top of the bell is suggested. Should this also be maintened above the oven insert?
3. Is a spacing of 50mm between the sides of the bell and the oven insert sufficient or should I increase it?
4. Should I use fireproof material inside the bell or would brick be good enough? I was thinking of casting my own bricks using something like perlite for high heat areas such as the bell ceiling above the riser.

Water heating.

I have experience only in building outdoor units with a 210 litre drum with fire underneath, enclosed in brick which we in South Africa call a "Donkey", and would like to do this inside the house.
I plan to fit underfloor heating, and consider building a tank 1,2m high with a circumference of 2,4m using 2mm thick stainless steel, with a volume of 550 litres.
It would have a surface area of 3,8m².
If I add 5 open ended pipes in the tank from top to bottom with internal diameter of 100mm it would increase the surface area to 5,68m², and the volume would be 500 litres. The tank would be also be heated during the day with a pumped solar system.
I want to place this next to the oven, to be able to use the same chimney, with a Batch box heating a 900mm x 900mm bell 1400mm high. I want to insulate the inside of the bell entirely.
I'll add a flue bypass to ease cold starting and to also release heat if water gets too hot.
This build is my biggest challenge and I have the following questions.
1. How does insulating the bell affect it's sizing?
2. Concidering the inside area of the insulated bell of 6,13m² and the added surface area of the tank placed inside the bell, would a 6 inch system work?
3. Is a 10cm clearance between the top of the bell and top of the tank sufficient, or should I increase the height of the bell?

If this is is not feasible I will decrease the size of the bell and design a heat exchanger with the maximum surface area to thermo syphon to a tank on the second story.

I don't want to increase the size of the system, for the sake of aesthetics. The doors of the 2 fireboxes will be next to each other and need to look symmetrical.

Ash removal.

I want to add grates in the floors of the fireboxes with removabal ash pans underneath to ease cleaning.
1. How will this affect delivery of primary and secondary air, and sizing of the air inlet?

Anyone with experience in building simular systems or who can point me to online resources or forums where I can find answers to my questions, your input would be appreciated.