Batch Rocket Design Question

Armed with a bit of knowledge from reading as much as I can find over the past 2 weeks I am now becoming dangerous and starting to think about a design to meet the heating needs in our living area/shop. The shop is actually a multipurpose 2,000 sq ft area that is used as part of our daily living space and therefore we heat daily, typically from late September through mid May, using mainly a Jotul wood stove backed up with an antique wood cook stove when it gets really cold outside. The shop rarely dips below 50F in the morning before we begin heating and typically we raise the temp 10+F in about 3-4 hrs. Unless the temps are really low outside, at this point we stop burning and the abundant southern Colorado sun will raise and maintain mid 60F temperatures throughout the day. Our primary goals with the batch rocket build will be to reduce our firewood usage through more thermal efficiency and store heat with the thermal mass to maintain a higher and more consistent temperature through the night.

Referring to Batchrocket.eu website and the Applications page, Peter shows a 3 barrel design (image below) which is interesting for a few reasons but I am curious if I can change the design in the following manner to prioritize thermal mass over rapid heating by replacing 1 or 2 of the barrels with masonry.



The idea of having the combustion core/firebox situated at about waist level is very appealing, especially to my wife. We are highly active but no longer youngsters, so it would be great to not have to bend down to manage the fire.

My current thinking is to use trapezoid paver blocks to replace the Peter’s lower barrel with a round masonry structure and build up either brick or concrete block inside as Peter did to support the combustion core. Then transition to a single barrel (not a double stack) to house the riser. Then have an adjacent bell constructed of paver block or brick.

I’m very curious to hear feedback if this seems like a viable design with a reasonable potential for success.

Hi Glenn,

Yes, all or some of the barrel bells can be replaced by masonry. Peter has a number of examples of constructing such builds on the batch site. There are also some very nice videos posted of construction.

If you make the firebox at waist height however, the riser with subsequent barrel over the top will need to be quite tall, thus the reason most people double stack a barrel to begin with and then create a bench bell adjacent. The riser clearance for an 8" system is a minimum 12" to the top of the barrel or masonry if you go that route. This means if you have the floor of the burn chamber begin at 2', the riser height is 4'10", and a 1' clearance, the stove top is now 7'10". Now you need more than two stacked barrels.

The concrete pavers are probably fine for the second bell, but I wouldn't use them for the bottom of the initial bell as the temps could still be high enough to degrade the material. Brick would work well here though. Someone correct me if I'm wrong on that bottom of the bell temp and the application of cement.

Glenn, keep bringing your ideas to the table--some drawings would be great too. For the secondary bell were you thinking a heated bench?

Thank you Daniel for your comments.

I didn't mention in this post that I have 2 wood stoves currently in the shop and will be decommissioning one that is an antique cook stove with existing 6" chimney, so I am limited to a 6" system.

I initially thought of using brick for the lower section below the barrel, the trapezoid pavers just presented a more simple way to make a tight cylinder.

I'll continue with the journey and begin sketching up and posting ideas.