Gasifier Update

I've been absent from the blog for a while. A few new things have come my way, and I haven't done very much lately that was blog-worthy. Among my jobs are learning Drupal (a website platform) and updating a database. Plus all the usual boring stuff... So I did get some time to spend on the truck, yesterday and today. Last I mentioned it was running, barely. One time it ran good enough to drive a mile down the road..... and it quit. I drug it a mile back home. The problem then was that a PVC joint had separated and air was sucked in instead of woodgas. Air is not a suitable fuel, so the engine died. By the time I figured out what had happened, I was out of battery power, and too far from home to just leave it. We hooked a chain to the bumper, and pulled it home very slowly. It bent up the bumper a little, but we made it.

Now the truck has a new battery, the leaks have been fixed and now...it still won't run. Confirmed good gas is present at the engine, battery is fully charged. It will start, and then die. Like it's getting too much air. I am continually tracking down the remaining leaks, but it hasn't gotten much better. Maybe there is one "big leak" that if I fix it then everything will be hunky-dory. It's possible, but I can't find it.

I took some photos of the current configuration. The Arduino is running the mixer servo manually right now:

The blower gets a switch:

Control wire to the servo goes into the dash:

 The final filter has been painted, and turned 90 degrees:

I built a decent check valve, as usual with leftover scrap. Consists of 2 bolts, 2" pipe, cutout from a hole saw, and an old brass bathtub drain. Cost: $0.00. It works great. Air can go in, not out. It's not sealed perfectly, but it's good enough.

Installed. The old port is now just for lighting the gasifier.

Random shot. Can you tell? The lip is full of condensate. The truck is parked the wrong way for it to drain out. At least one of my welds is watertight.

Truck in the daytime. Note the blower pipe is missing. It's removable.

 

Here's the blower exhaust pipe, with a rain cover made from PVC pipe.

And finally, a video. You can hear the truck run and die. It does this consistently, given good gas. It's gonna be sweet to hear it run right. A lesson in patience.

Rocket Mass Heater

It's that time of year again... Hope you have plenty of wood split for the winter, I know I do. At least some of you must burn wood for heat in the winter. If so, good for you! Heating with wood is a lot of work and mess, but it's much cheaper than your other options, namely gas, oil, or electric heat.

It does seem to take a tremendous amount of wood. Unfortunately a lot of that wood goes right up the chimney, as heat and smoke. Extra wood to burn means more cost, extra splitting, extra storage, and possibly running out. What if there were a small cheap stove that got better "mileage" and was DIY friendly?



Let me introduce you to a true econobox, the Geo Metro of the stove world: the Rocket Mass Heater. It's dirt-cheap and super efficient.

A Rocket Mass Heater (RMH) uses 80% less wood than a standard stove - AND - you only need to fire it once or twice a day. The large heatsink stores the heat from an small intense fire in the morning, and radiates this heat all day. The exhaust is only about 100 deg F. No smoke, just steam and CO2.

Here's what you're seeing in the picture: The wood and air go in through that little "bucket" in the foreground. The heat radiates from the 55 gallon drum, enough to heat a kettle of water on the top. And the large masonry bench is warmed by the exhaust, capturing all the energy before it goes outside. Comfy bench, hot barrel, wood in a hole. Got it.

The wood actually sticks out of the hole, but only the inserted end is burning. Flames from the end are sucked sideways into the heat riser. The heat riser is an insulated pipe where all the smoke burns at high temperature - this is the "rocket" part. The extreme heat creates a powerful draft which drives the system. This flows into a barrel which surrounds the heat riser, and back down into the base. The barrel serves to radiate some of the heat, and cools the gases, improving the draft. The exhaust gas enters a large thermal mass which stores all the heat remaining in the gas, and slowly releases it to the room.


Video tour of several installations:

One being built at a workshop:

The RMH is by far the cheapest stove you can build. You will need a 55 gallon drum, stovepipe, perlite, some firebrick and plenty of "cob" (clay + sand + straw). This is a triumph of DIY design over mass-production. Anyone can build one of these, operate it and get "extreme MPGs", so to speak. Read more about these at Permies.com, get the book at Rocketstoves.com, or just watch the videos on Youtube.

I plan to build one, it looks fun and very easy. Stay tuned...

The moment of truth

At long last I have gotten all the pieces of the gasifier in place. I haven't gone through the leakproofing yet, but everything is hooked up. Here's the plumbing under the hood:

The air cleaner still fits just fine:

The final filter for the woodgas, and the bilge blower:

The plumbing from under the truck:

Here you see the same pipe, going back to the hay filter. Further under there you can see the pipe from the condensate tank coming forward to the hay filter.

The pipe from the condensate tank, ready to go into the hay filter.

Again my oven-heating PVC trick, made a nice flange for this pipe. Metal window screen, this needs filling with hay.

Some hay for the filter. Used about a quarter of this.

All hooked up.

And I added a jar to catch soot and condensate from the cyclone.

So I decided to flare some gas, and see what happened... It flared beautifully, although I could tell there was air getting past the leaks. Still, I went ahead and flared it under the hood - perfect flame, pointed right at the wires on the firewall...OK, enough of that! So the next step....I tried starting it: And it started. It ran a few seconds, and quit. I have to get the air leaks fixed, and advance the timing. But it ran, I heard it! It lives!!

You can hear it too - I have a video.  It's a little dark, shot in the evening, but you can hear it run (starts at 3:35). Enjoy!