Mark Log
Wednesday, October 26th, 2016
Spoke to Marcin and finalized BOM. Added link to BOM in presentaion: https://docs.google.com/spreadsheets/d/11pQpi5mwnDAgyS1EWNWjtcWksAiQFCGRM11gsAuMC9k/edit#gid=0 Researched insulation and charge controllers and voltage converters. Hopefully found good solutions. Could probably design simple buck/boost converters myself in the future. Will look into it.
Tuesday, October 25, 2016
Quick sketch of wiring added to Google Slides presentation. Also updated Bill of Materials to what will hopefully be its final form for this build. Not sure yet exactly how much compound to order. Check Tuesday, October 18th, 2016 entry for calculation of free space between pipes between modules. I am also assuming there will be fasteners, fittings, and steel plating available at the farm for clamping all pipes together and attaching hose. Have reached out to supplier of silicone glue inquiring as to its removal once cured in case we want to salvage the modules for a later iteration of the TEG. Awaiting response. Just remembered, we still need less expensive thermal insulation in between modules and around entire generator. Foam sheets cut to fit?
Monday, October 24, 2016
Fritzing software not making much sense to me. Also not sure how to regulate the voltage from the TEG to a stable 24 Volts. Probably won't have time to solve this problem before the build, but we will at least have the TEG working and producing measurable voltage and current. As Marcin said, this build doesn't simply stop after the workshop, so there's always the next iteration to look forward to. Also cannot find a good putty to insulate in between the old and hot pipes in between the modules that isn't going to cost us over $100. Maybe we can just cut some foam to fit in the spaces. The putty would also jeopardize our ability to retrieve the modules after the build since it hardens like ceramic or concrete, so this is probably for the best.
Wasn't able to meet with Alex for a crash course in welding, either. AND I still can't find the hole in my sleeping pad. Not a great week, but this week will be better, and I'll be headed to MO on Monday, so lots to look forward to.
Updating the BOM tonight since we need to get things ordered soon. Hope this works!
Wednesday, October 19, 2016
File:Tegfreecad.fcstd Uploaded two FreeCAD files detailing the geometry of the TEG modules laid out on a pipe. Created new BOM with links and added it to the end of the presentation. Researched pressure and safety regarding the hot water reservoir, but didn't find much. Need to get a pressure relief valve that can be set to about 140 degrees C. Is the 50% efficiency already taken into account on the datasheet for the TEG Modules? Talked to Marcin on phone. Great conversation, lots to think about. Now prioritizing finding experts to assist and review designs and BOM, getting the BOM finalized, and making an electrical diagram of the system and its connections.
Tuesday, October 18, 2016
Calculated volume of insulating material needed to fill the 3.4mm tall spaces in between the individual TEG modules to insulate the cold water and hot water pipes from each other everywhere that a TEG module doesn't connect them. (152.4×762-40×40×24)×3.4×4 = 1.05711168 × 10^6 mm^3 or 35.745198 fl oz (fluid ounces) or about 1/3 gallon for the space between and around each TEG module total for all four sets of 24 TEG modules sandwiched between a hot and cold pipe.
Added FreeCad screenshots to Google Slides presentation. Added basic build instructions as well.
Made some changes to design based on Marcin's feedback such as adding a pressure relief valve. Plan to speak to him tomorrow and have completed BOM by Thursday night.
Monday, October 17, 2016
No internet at work but was able to work on FreeCAD designs. FreeCAD seems extremely tedious and cumbersome to use, but it's also the only non-electrical-focused CAD software I've ever used, so I really can't say. Completed detailed layout of the individual TEG modules on the steel 2x6x30in pipe. Not sure how to share file at the moment, but will add screen capture to Google Slides presentation.
Sunday, October 16, 2016
Rough Google slides presentation up. Included sketches of basic TEG layouts with calculations on spacial arrangements. Compiled various design notes from Marcin and others. Researched products to be used, included links. Need to finalize those asap. Read through Marcin's Google Slides presentation on the hydronic stove: http://opensourceecology.org/wiki/Open_Source_Hydronic_Wood_Stove
Also looked at this on the heat exchanger: http://opensourceecology.org/wiki/Wood_Stove_with_Heat_Exchanger
"The pellet burner fires a stove which can also run on regular wood. The flame heats up a heat exchanger which produces the hot water or water mix for the teg. The hydronic heating Loop will be a separate heat exchanger inside the same stove which then feeds the water to the floor. The teg is independent of the hydronic water heating at first. However the teg has a cold water line running from the aquaponic ponds to provide the cooling water. That water is pumped while the hot water from the stove Rises through the TEG by convection." -Marcin
Fri Oct 14, 2016
MJ notes - let's get the temperature difference up to 100C with glycol or sugar water.
Thursday, October 13, 2016
Been out of town. Did basic Google and YouTube searches for existing implementations of TEG systems, DIY-ers, and TEG knowledge. Reviewed existing material from wiki on TEG. Reviewed Marcin's log of feedback from ITS board outreach. Learned how to create wiki account and create a work log. Plan to have basic first drafts of designs up tomorrow (later today). "...TEG's fill factor is ~50%, meaning cover 50% surface area of the hot tube... And because only 1/2 of the 60C drop is applied on TEG..." Follow up on these comments from Zhixi... Sounds like we need a different design or 5x bigger system to achieve 100W?
