Shane McKenna wrote:We acquired our fire brick for building 6 RMT stoves. We are going to build 3 in the basement, and 3 in walipini greenhouses.
Our plan is to not build 1 stove to try and heat the whole house, rather build 3 to heat zones in the house. Each will burn long enough to keep the thermal mass warm each day, and to heat the central core of the house. The central core has 2 foot thick rock walls that run from the basement foundation, up 2/3 into the next level. They are also going to be situated to warm the earth on the south side of the house were we have passive solar and growing rooms. During the day, solar collection and venting will circulate the heat from all the sunrooms into the home, at night the RMT stoves will keep the soil mass temps up. We plan on growing all winter long at our above 6000ft elevation. In addition, we are going to put floor vents in on both the north and south sides of the home to help get a convection loop working throughout the home. If we were starting from scratch, we could build a home that is far more efficient to heat with 1 RMT stove, but working with a pioneer home with multiple additions, we have to work with what we got.
Our hope is to get at least one of the stoves built in the basement this winter, and one walipini built this summer.
Each of three Walipini greenhouses will also have a RMT stove. We are considering growing tropical fruit trees in one of them.
The fire bricks are un-used. They had been custom cast for a steel mill, and are rated for 3000 deg. They had been sitting on pallets for many years, and were basically nearly solid blocks of ice, brick, and rotten wood when we loaded them. It was quite a project busting them out of the ice, and digging them out of the dirt that had built up around them. The largest bricks are 5 x 9 x 4.5, the medium bricks are 6 x 9 x 3, and the small bricks are 3 x 9 x 2.5. All of the blocks taper slightly, so it is going to take some creative stacking to build a stove. I laid the design out in Solidworks, and it is possible to build a 6 to 7 inch system with the blocks and only cutting 1 inch off of one block. With all of the tapers, it will look like it is built by a drunken mason, but getting high quality fire bricks for cheap is going to make the extra effort worth it.
We are going to document the process, and keep records of the performance, and costs. I will post the progress and results as we go along. The costs so far, $200 for the bricks, and $65 in gas to haul them, and a stiff back from digging them all out.
Shane McKenna wrote:I got some free heavy wall 8" pipe (.25" & .375"). Enough to do one of our exhaust runs. I am going to a scrap yard next week and going to root around for the rest of our metal parts needs for our first build. I have a bunch of barrels reserved for both our RMH, and for thermal mass in our greenhouses. I love going through a pile of stuff and finding things I can adapt.
We will be doing one of the builds this spring. I live a couple of hours away from our family property, so I have to plan blocks of time to go work on things.
My Father-in-law who's property it is, and I tend to be careful planners, going over multiple options and making revisions until we have a solid design. So we are working on these now.
We are going to build at least one of the RMH units in the basement this spring, and one in a Walipini this summer. That will give us both experience and results to work with before building the other 4 units.
One of our challenges is the way this house was built and added onto over 125+ years. Some of the quirks of the house are benefits, and many have significant down sides to heat flow. One of the great things about the house is that part of the central core is 2ft thick rock walls that extend up 2/3rds into the living floors above the basement. That is were the first stove is going. Those walls are massive thermal mass storage. One of the walls of this basement room is on the south side of the house, so rather than fight the heat loss through that wall, we are building a greenhouse on the outside of that stone wall. The heat loss through that wall will warm the toes of our winter planting. My Father-in-law grew tomatoes in a simple plastic tent on that wall up until a few weeks ago. He had a fan blowing warm air into the tent, and he could have kept going but the yield started to drop off to the point that he didn't want to use the electricity to run the fan anymore.
It will be super exciting to see how much heat we capture from the RMH next winter. There is a small window right above were the burn chamber is going that we can vent directly into the greenhouse on those 15 below nights. I see no reason we cannot grow lettuce greens and keep tropical plants through the winter. We are big fans of kale and spinach green drinks, so our primary goal is to have at least some of those going all winter.
Thanks for asking, we will keep the project challenges and designs posted as we go.