Episode-1205- John Fedock on Wood Gasification — 26 Comments

  1. I really enjoyed this show. John Fedock has shed light on a lot of great ideas that I myself have been looking into. He seems to have figured out how to put these ideas into action. It would be great to see his finished products. Definitley going to check out his site.

  2. John Fedock=A humane type person for the 21st Century using his skills, developing more skills, and following his curiosity and bliss into shared solutions that follow the paths of sustainability, resiliency and self/community co-reliance. You’re no piker yourself, Jack, in those respects. Loved it, and thanks so much for the introduction.

  3. And could we get a show with the topic being “rebuilding with the collapse in progress.”

    You talk about it alot, but it would be cool from a philosophical and practical perspective. The motivation shows are my favorite.

  4. I really enjoyed the show Jack. I live in northeast Indiana and it was nice to get northern point of view when it comes to permaculture. Or at least something close to my state. I love to hear about greening the desert and I am all for it. But it’s nice to get something a little more practical for my area. Thanks.

  5. This was a great interview. I hope John Fedlock can come back on when he gets his gasifier up and running, and he can tell us how it works.

    The solar air conditioner has been discussed endlessly on the TSP Forums. Glad to see that it is becoming a reality!

    • What needs to happen is a fusion of solar thermal, gasifier, and micro-CHP technologies from an open source project or projects. Something modular in design.

  6. I wonder if it would be possible to modify Larry Dobson’s version of the gasifier and stack the functions with the heat exchanger to heat the zeolite in the adsorption cooling system to expel the water and recharge it?

    John – if you are going to keeping the information opensource I’m sure the guys at would love to link to your page.

    • That is an excellent suggestion! I have written posts about “build it solar” (great site) but never thought of adding Larry’s design to the site. I will work with Larry to make it happen. Thanks!

  7. On the Central A/C condensate drain discussed; using Permaculture principles of stacking and linking elements you can harvest every ounce of water in a Sub-Urban residential application. Attach onto the existing A/C condensate line and run the 1/2″ PVC drain pipe into a Greywater Reed Bed that overflows into a tropical mulch-pit banana circle that overflows into an in-ground aquaculture pond that feeds an aquaponics system set of growbeds that becomes the bio-filter for the pond…

  8. talk about a sleep show. i started this thinking ‘meh’, but i listen to every show anyways and wow am i glad i listened to this. a great show that i learned a lot from and thoroughly enjoyed.

  9. Best technical interview I’ve heard in years. I was in nerd heaven listening to thermal efficiencies, exhaust quality, heat exchanger design concepts, flow/pressure constraints, suction head, etc.
    Thanks John!

    Looking forward to your completed gasifier design.

  10. John,

    Have you considered using not only the exhaust from the gasifier itself to preheat, but also from whatever implement is being powered? Of course you don’t get the effects until the engine is running, but that is a lot of heat going to waste.

    • Tim,

      You have an excellent point! If you set up a heat exchanger to capture the waste heat from the generator you would further increase your overall operating efficiency, which means less fuel and cleaner gas. A trade study should be conducted to understand how much efficiency you could gain vs just using more wood. Then you could make an informed decision if the cost of the heat exchanger was worth the additional efficiency, which highly depends on how much your fuel costs are. I have not considered this at this point in the prototyping phase but will evaluate the practicality of this idea for the final optimized product. Thanks for the great suggestion!

  11. I too was excited too hear about the Lennox system but it’s just marketing. This is Lennox’s way to get on the green tax credit band wagon. The solar thermal systems that were discussed on the show are just that, solar thermal, not solar photo-voltaic (PV). The Lennox system is solar PV because they want to sell you solar PV panels to make you feel good. The Lennox system is light sabre technology. The solar thermal system is real but only for big massive buildings. But no one is stopping the first DIY m.aker from doing this

  12. Hey, great show. Just one note. 22min in you we’re talking about The refractory part with a Portland cement content. Just a note I’ve been watching the videos from Paul Wheaton on the kick starter about rockets stove fires and in that training presentation they were adamant that you don’t use Portland cement in very high temperature scenarios. Is this an issue.? Or are the temps in a gasifier low enough not to be a concern?
    Thanks so much.

  13. This is an issue and something I will be testing / addressing with the prototype build. I also have the videos but haven’t watched them all. Now I am interested to hear what he suggests instead. The temperatures in a rocket stove will be much hotter then a properly operating gasifier, but both are probably not suitable for Portland cement. I poured my first inner hearth based on some incorrect info I read online. I am going to test the hearth I already made to see how long it will last but I’ve already accepted the fact that I need to build another one with a better refractory formula. I will probably use a formula similar to the one described in the videos! thanks for letting me know.

  14. Running a few weeks in catch-up mode, but wanted to make some comments on the refrigeration without a compressor. I had cousins back in the 1950’s and 1960’s that used a natural gas powered refrigerator, and you can purchase kerosene powered ones today from Lehman’s. These are all modern versions of the original “Icy Ball”, which was patented back in the 1920’s, and that I played around with as a kid. See the Wikipedia page @ for technical details. Adding a few valves and sensors and connecting to an embedded controller, like the Arduino John mentioned could remove all of the manual operations discussed in the article. This is a simple enough system that it may be possible to construct one as a DIY project, although the internal pressures of the original Icy Ball reached something near 250 PSI. Just my $0.02 worth on another possible place to look.