Recommendations For Modifications On Wood Stove

I am modifying an old heavy steel fireplace insert and would like some advise. I've added secondary air, water lines and baffle at the top of the fire box. Inside the barrel is a 6" riser. My plan is to come out the back of the barrel at the bottom and go down to a mass along the ground. Will it work? Do I need the secondary burn area at the top of the box since I'm doing the riser? Would the water line be better in the box or the drum?

BTW the box shown is the interior fire brick.

Hmmmm, lots of questions... To start, water lines inside the firebox or any part of the combustion zone are bad for two reasons. They will rob heat from the fire, cooling it and making the burn less efficient and complete; and if the pump should stop for even a few seconds while the burn is hot, the water will flash to steam and cause an explosion. Inside the drum is still not completely safe, as ambient temperatures could be 500F or more depending on conditions. Wrapping copper tubing around the drum has been done successfully, as has embedding a non-pressurized water tank in the heat flow path and running copper tubing through that. This last is by far the safest method, and will give more constant water temperatures as well.

You have the firebox lined with firebrick (good); what is the riser made of, and how is it connected to the firebox? A riser from the top going straight up has been found not to give the beneficial turbulence that helps complete combustion. Are you making a batch box with a door, or an open J or L configuration? What are the internal dimensions of the firebox, riser, and clearances? How much mass and what sort of flow path are you planning?

The water line is open into a tank so pressure won't build up. I'll probably raise it into the barrel. There will be a cylindrical riser 6" I.D. x 8" O.D. with perlite mix insulation. The box has a sealed door with directed air input. Nothing is written in stone. Just looking for better options. Will the secondary burners be needed since there's a riser?

Sounds good. I would make the riser 6" x 10" o.d. for 2" of perlite-clay. Are the secondary burners in the stove made of metal? If so, they will likely burn out with the greater temperatures in the core. If you do have a riser that generates turbulence at the junction of firebox and riser, the current secondary burners would be superfluous.

What you are making is essentially a batch box; have you studied the research published on batchrocket.eu? The best dimensions and configurations have been worked out and shown in charts. Primary air would come through the door, and secondary (preheated) air introduced just at the port between firebox and riser.

Do you think I will need the baffle since it's a rocket stove? Also does the riser need to be in the center of the barrel?