Month: December 2019

Managing Hot Water

Talking with a weekend friend the other day who is starting to contemplate country life full time, she mentioned it had occurred to her in the shower the other day just how nice a hot water shower can be. In fact, she continued, she believed it to be an essential element for survival.

I added to her declaration that the shower needed to be at least under 45 lbs of pressure or I could never be satisfied. But I said this after a summer of almost entirely cold showers with no hot water at all. This was mostly by choice, but the best hot water heater I had during the summer would have also heated the house, which would have just added to the cooling issues of summertime.

When I first came here 18 years ago I had a gas hot water heater in my RV, and that was ok sometimes, but in winter, with freezing pipes; often that hot shower–or any running water at all, was unavailable. Still, even back then I understood how valuable hot water could be, and have spent a fair amount of time over the years making sure I could cover that need.

For several years now I have been heating water with wood. It started with a small Appalachian style coal(wood) burner water heater attached with a thermosiphon to an old water tank. Fire it up and maybe add wood a couple times and then close the pressure relief, turn on the 12 volt pump and shower as long as I wanted.

I also used to play with 2-300 feet of black poly pipe in the sun to avoid lighting fires in summer. Now that I am in this house (I use the term loosely), the ease of that little stove or even the poly pipe in the glass covered box are unavailable. And my aspirations have moved further on.

I still am heating water with wood, but now it is a sophisticated rocket stove, and every year there’s a new type to play with. It started with copper coils on a 55 gallon barrel, and now it is a 20 gallon tank inside a brick and clay “bell”, extracting heat from the DSR.

I’m actually quite proud of all the different ways I have played with producing hot water, and the latest toy should be arriving soon, an evacuated tube solar water heater. True to form I will not be following recommended procedures, and perhaps I will waste a little time reinventing the wheel, or perhaps I will find a way to make do with much less than the recommended equipment.

I have already found I can get by with smaller pumps and less energy and still enjoy similar results with many of the much more elaborate and expensive solutions.The new solar project will be a similar process, finding out the extent of it’s capabilities and then making use of them

When I built the house I did anticipate the possible use for radiant water pipes in the floor, although with my limited budget I had no idea how I might generate that much hot water, or even how I might get it through the pipes. Today my budget is less restricted, but continuing in the use of renewable resources puts a whole different spin on things than just buying a new propane hot water heater complete with expensive automatic controllers and pumps.

For the time being the solar collectors I’m playing with are more an experiment than a completed plan, but they do seem to have enough promise to invest in, and then fully explore their potential here.

One of the keys to Permaculture Design is to have several backups for every important system, and since hot water is one of those systems I continue to investigate and establish multiple ways to generate hot water.

DSR 2019 build

Well, a new heating season is begun and with it a new iteration of the previous Rocket stove, called a Double Shoebox Rocket.

The group over at the Donkey forum did some experimentation back in 2018 coming up with this concept, which was later abandoned by Peter van den Berg, the chief experimenter on the project, as being too unreliable.

By the time he had moved on to a different design I had already started building, it was getting colder, and looking at the elements that seemed to make the DSR run away with the burn, they did not seem as relevant to my design, so I just continued to build according to his best guess dimensions.

My 2018 build used a number of walls that were simply formed of clay, or a clay perlite mix, and a couple of the sides around the water tank were taken from an old washing machine, with some fiberglass insulation hastily fastened to the inside of the walls, with clay slopped around the top and edges to give a seal.

The door to the burn chamber, as in many projects done on the cheap was a problem until I finally bought a couple pieces of neoceram stove glass, which cost more than all the previous stoves from the last several years.

While this new glass has proved very durable, having a door that really is robust requires more than just a glass pane, so that is still in the development phase, although I’m pretty sure I have a workable solution which will likely happen sometime during this season. For now I continue to get a potholder if the glass is hot, and as gently as possible remove it and then wedge it back into place.

The other main change is the use of bricks to give a substantial continuous exterior that is well sealed and even looks a little better.

One other important note, my exhaust was set up for a low temperature ground level “stack” and to use the push of the j tube rather than the pull of a draft. Since the first batch box conversion about three years I found it necessary to install a fan at the end of the exhaust pipe to aid with the draft. This totally eliminates smoke at start up and keeps the draft more even.

while it may appear the smoke is being pumped into the ground, the downward tube is actually wide open at the seam, this arrangement helps prevent sudden gusts from totally disrupting the draft
The brick exterior is continuous back to the poured concrete wall as I continue to remove clay from the previous construction. the removed clay goes right back into the new build
note the wet perlite clay mixture formed in place around the DSR core. The stack/exhaust is on the floor at the right side of the shovel
the clay perlite insulation layer continues across the concrete wall in back
The second chamber is now well defined and the brick courses are starting to grow
Note the rectangular passage on the right where the exhaust comes in to the first bell from the secondary burn chamber. The rim of the duct to the water tank “bell” can be seen just opposite this entrance and further down in the chamber
The right side of the water tank shows the location of the duct from the first bell just visible above the top of the front bricks
overall layout of stove. note exhaust moves from right to left through the chambers and at the bottom of the water tank chamber it turns back and flows under the construction to the exhaust “stack”
salvaged glass stove tops are sealed with wet clay to the top. Note the left side galvanized pipes exit and the blue pipe insulation for the hot water outlet
proof of concept, the first fire verifies the exhaust, now the drying process begins
looks just like the pictures I saw when I first started last year, note that the bricks are joined with a clay “mortar”, if I want to rebuild, everything is easily recycled with water as the solvent
I usually have a small piece of ceramic fiber board over the glowing section of the stove top. Temperatures are way hot, and after passing 1000 degrees F it just registers as “HI”

cooking can be done here, very carefully, but I like the idea of more insulation to increase efficiency of the burn. The second chamber still has plenty of heat for a more reasonable cooking surface, and even the water tank chamber can keep things warm
with the top cleared and clean

DSR (Double Shoebox Rocket) revisited


So it’s getting pretty cold outside, and when I built the last version of my stove I promised a breakdown analysis after I had used it for a season and had a chance to sort out my experience. Now that I have rebuilt the beast it seems the time is here to write about it.

First I would say that overall it performed pretty well, the weakest part of the thing being the door. The visions cookware lid I started with did work, but I would not plan on using such a thing except in a pinch. Eventually the first one cracked, primarily from physical shocks because it really does get too hot to handle at times leading to bumps and drops, and once hot it will use any excuse to crack.

Over the three to four month life of the stove there were numerous tweaks and while the final product worked, it would never have lasted another four months without many more overhauls.

My building style was primitive, using lots of clay and perlite, which was always sufficient in the original rocket stoves I built, but with the more compact and intricate design of the DSR bricks are really the way to go for all vertical surfaces, not just inside the firebox/batch box. Also bricks give an element of speed to the construction, and the finished product is structurally more stable. With clay walls on much of the old stove, cracks were commonplace, and I often worried about them just falling completely apart. If you do want to use clay, make sure it is a continuous mold type process. Forming one wall one day and then adding to it or building an adjoining wall the next does not give a reliable bond.

The water tank was the next area of interest, primarily because it was an issue I had to revisit many times, especially after one spectacular failure. My theory that pex could withstand temperatures in excess of water boiling was good only to a point . Hot, therefore soft, pex under extra pressure will blow out. Use all metal fittings inside the heat chamber and for a distance outside the chamber, and of course, when heating water, always have the system open so steam can escape safely. Pressure relief valves are a real good extra insurance in case one forgets to depressurize the system.

Soot was present everywhere the exhaust touched , except the parts that got the hottest in the burn chambers. The thought occurred to me that I had basically turned the entire downstream part of the stove where heat was extracted into a creosote trap, and future builds will have to accommodate an easy access for periodic cleaning.

Future builds will also need to be more efficient, and since start up and cool down phases of the burn are the most problematic, shortening those periods compared to overall burn time will be a major concern. Quality dry fuel will become a major goal for operation of the next iteration of the stove.

Recently I read more about the continued development of the DSR II and it has taken some interesting turns. I’m not sure I will be using all the developments, but at some point I will likely be adding a short riser at the back of the firebox. That will likely wait for me to get some ceramic fiber board, so for now I’m just using the old DSR design.

original visions lid, the crack is visible on the left side running under the handle, and I continued to use it till it cracked into several smaller pieces later on
this hodge podge is the water tank enclosure As the winter closed in, my hurry to get the stove functional meant many makeshift connections and very iffy seals. The forced draft kept a negative pressure inside the stove so leaks weren’t really a problem, but it would always be best to have everything tight as a drum


I broke down and bought a 10×10″ piece of neoceram glass–expensive (50$) but a good investment
this is before the old stove was finished being built
taking the stove apart, note the soot in the oven chamber but not the firebox area
getting a start on the base of the next DSR, note the exhaust has been extended and turned toward the left in preparation for the changed position of the water tank and the exhaust exit from the stove

I was a bit remiss taking pictures as I dismantled the old DSR, and obligations elsewhere meant much of the new construction was not overly documented, but look at the next post to see how the new DSR changed.