Thermoelectric Power

Homesteading & Country Living Forum

Help Support Homesteading & Country Living Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Well I decided to take a chance and gamble on this to the tune of $300 for a DIY system. If it works out then we should make at least 1kw of power from it every 24 hours and possibly up to 2.4kw every 24 hours during the winter when the heats on. Hopefully it will help with generator run time during the low solar winter months. A big added bonus for us is it will also let us pump some heat to parts of the house that don't get any now via the cooling system for the modules. I think being able to move some heat around the house probably had as much to do with my decision to spend the money as making power did, maybe even more. The heart of the system will be 2 of these units deconstructed and modified for my purposes.

12V DIY Thermoelectric Cooler Refrigeration Device 8-Chip TEC1-12706 576W | eBay

I have a bunch of new old stock heater cores I'll use to remove the heat from the system and put it where we need it, IE: the bathroom and my daughters room.
 
Just wanted to point out I don't really expect these modules to last. That's part of the plan believe it or not. This was the least expensive way I could find to get the hardware. I've already found higher temp better quality TEG modules to replace them when they fail. Buying the hardware each piece by piece would have more than doubled the price without the modules. It was those little Aluminum water tanks and the Aluminum heat sinks I needed to make this work.

If this system does nothing more than move heat around the house I could still call that a win. Wood stove "central" heating for $300. lmao It gets cold in the bathroom and kitchen, my daughters room isn't as bad but it could use more heat too.
 
Hi guys got a question for you all including @Neb . I need a decent soldering iron and I am looking for suggestions, hopefully with links. For a good soldering iron that won't break the bank but will always get the job done, I've had it with the junky one I've got!
 
I have a few irons that I use. I have a small one for electronic work (I think it is around 30 watts)
A 200 watt Weller for the run of the mill soldering and a 1500 watt that I use for the large lobs like water and fuel tank fittings.
You can't do it all with a single size.
 
Started actively working on this project today. First off I want to start with a good foundation. Which in this case is some inch thick iron or steel scrap I bought for unknown reasons one day when I saw it. It was one of those cases ten or so years ago when I said I'll need that one day, guess that day was today. lol So I found it and cut it in three nearly equal pieces of roughly 3x21 each to make a nice thermal mass and help temper the ups and downs of the woodstove. We all know thermal mass is effective in slowly distributing heat and in this instance I am hoping it will also keep the stove from overheating the thermoelectric modules and help them maintain a more steady heat without those huge peaks and valleys woodstoves can have. I have a ton of cleaning to do on them and I'm thinking I'll weld them together in to a single unit roughly 9x21 and maybe put handles on the ends to make handling it easier. Haven't decided yet but I may weld another 1/4 plate on top to make it nice and flat & even across the surface. Does anyone KNOW if this will also keep the top surface from getting as hot as the top of the stove gets? I sure hope so! lol
 
I did get them clean enough for a test run over the next few days to try and get an idea what kind of difference it makes. I won't honestly be able to tell until I get the IR thermometer, but I should be able to tell if it tempers the heat some. They are on the stove now the little fan finally cut off, wonder how long it'll take to come back on sitting on top of them?
 
Biggkidd said:
This is for electrical stuff. I generally use a torch for copper pipe and such.
Click to expand...
15 to 30 watts is plenty for board work and smaller wires say 18 gauge or less. Weller makes good icons with a separate controller. Pace makes high quality irons, but likely overkill if you aren't doing board level stuff on a regular basis.
 
Thanks @Bacpacker

The little fan just turned back on so that took almost 20 minutes but I did pre warm the steel. Also did a quick internet search and according to the online calculator for steel that bit I added weighs in at over 53 pounds.
 
I can't wait to get the IR thermometer but I think this heavy steel is working better than expected. The stove radiates more heat out of the sides and less, a lot less rolls off the top. In fact none rolls off the top like it use to. I think this is going to work out. I expect a lot of people have tried this but I doubt any of them controlled the stove temp well enough. Looks like this steel plate may do it for me. And before anyone says it yes I a will lose performance (make less power) this way but I will steady the output and increase the longevity to me that's well worthwhile.
 
If you are building electrical projects the controlled temp soldering irons I have used all worked really well. For bigger repairs that don't require a torch i am always on the lookout for old but good american made soldering irons. I can build cables for bicycles and motorcycles with the larger solder guns and a supply of cable ends.

The IR temp gauges are really handy. The last shop I worked in I used mine for checking if multicylinder engines had all cylinders working and also checking how the cooling systems were working on ATV's and side by sides. I used to check the wood stove and if it was really ripping it would register 600+ degrees. The gauges are also handy for getting your drinks and porridge just right.
 
I ordered a bunch of stuff for the project some from Amazon and the rest from Ebay. Anyway I’m a little upset because I purposely ordered a IR thermometer first thing since I need to be running some tests while I wait for the other parts some of which could be a few weeks. I’ve been checking the mail daily since Amazon said it would be here by Thursday. This morning I went and checked Amazon to see if maybe it got lost or something. No it hasn’t even shipped out yet but every other piece has. @#$%^&*()_)(*&^%$#$%^&U*IOPOI(UYTR$E#$%^&*(O)P)O(I*U&Y^%$#%^&*()
 
@Neb I followed your advice and ordered a roll of 60/40 lead tin solder just incase the ancient roll I have isn't the right stuff.
 
The "test" or 12 volt single unit of 4 came in today. So I got it all taken apart and cleaned the pieces, once I get the thermal paste I can reinstall them in reverse. But that's about all I can do until the temperature gun gets here and I can see what I need to use for a thermal buffer. Although I do believe the 1 inch thick steel I have on top of the stove now will work for that. I'm not as worried about getting 100% performance I'm more concerned with longevity at 50-75%. I am going to have to figure out how to handle the two outside fins on the aluminum heat sink as they are about 1/4 longer than the rest.
 
Does anyone know where I can get bi-metal by the temperature it moves at? Ideally something that starts to move about 120c or 250f with enough force to lift a few ounces. Something like the strips they use on the bottom of stove fans.
 
Last edited:
Biggkidd said:
Does anyone know where I can get bi-metal by the temperature it moves at? Ideally something that starts to move about 120c or 250f with enough force to lift a few ounces. Something like the strips they use on the bottom of stove fans.
Click to expand...
A few ounces?

No

If you know of a make and model of stove maybe search Repair Clinic.com for a replacement part. If you find a part number compare with Amazon since shipping makes a difference...

Lacking that could a thermostat control a solenoid?

Ben
 
I was just looking for a secondary mechanical device that would pick at least one side up if the heat started getting to high. In all honesty I think the 1 inch thick steel is going to moderate or buffer the heat enough. It heats up and cools off so slow compared to the stove top. I don't think it's temperature ever gets close to what the top of the stove does. I've had a large pot of water on top of the steel for a couple days and it hasn't boiled once whereas it often boils on the stove top. Where the stove might get to 5-600f I doubt the steel gets much over 250f, BUT it also doesn't get the lows either it maintains for long periods.
 
Last edited:
Biggkidd said:
I was just looking for a secondary mechanical device that would pick at least one side up if the heat started getting to high. In all honesty I think the 1 inch thick steel is going to moderate or buffer the heat enough. It heats up and cools off so slow compared to the stove top. I don't think it's temperature ever gets close to what the top of the stove does. I've had a large pot of water on top of the steel for a couple days and it hasn't boiled once whereas it often boils on the stove top. Where the stove might get to 5-600f I doubt the steel gets much over 250f, BUT it also doesn't get the lows either it maintains for long periods.
Click to expand...
The water not boiling could be a sign of an issue. The plates may be acting as an insulator. The Thermo electric cell need heat flux (heat moving) to work.

Ben
 
Neb said:
The water not boiling could be a sign of an issue. The plates may be acting as an insulator. The Thermo electric cell need heat flux (heat moving) to work.

Ben
Click to expand...
I'm thinking that's a good thing. I hope they are acting as insulators that's the whole idea. I need to buffer the heat to manage it. These cheap modules have a upper heat limit of 150c or 300f. The expensive modules can go as high as 800c from what I've been able to find out, with several ranges in between. Again they are EXPENSIVE and I'm poor. lol More importantly a household wood stove may get up as high as 6-700 f when the fire runs away but in most cases or most of the time the stoves tend to stay more in the 250-400f range. I'm hoping and trying to do the research to find out but I'm hoping the steel will buffer the highs and lows holding the modules in the 200f - 250f range without the wide fluctuations that stoves go through in the normal course of being used. Those high temp modules also require those HOT 300-700c temps to work. I know I don't need or want that kind of heat. My goal here is to make something anyone can copy using cheap & common parts that actually works. If I can make all this work out I also have thoughts to extend this further to a mass type power generator using fire and ground temps to work. Think a fixed fire powered power generation unit or possibly a portable unit that uses simple mass to moderate the temperatures for use. Where I live the year round ground temp down 6 - 8 feet is 58f and even at 3 feet deep would work year round for the cold side using water and pipe for heat transfer to the earth. So imagine if you can a large ammo can sized heavy massed fire powered generator. I am of the opinion that everyone who has tried this never tried buffering the temperatures using mass. I may very well be wrong but I decided to spend the money to try and see for myself, If I can make it work I will share the idea freely for others to copy. Another point is the wide temperature fluctuations of a normal woodstove appears to shorten the life of the modules. Again I am hoping keeping the temperatures more stabile will help cure this ill.
 
Pot of water

Using a pot of water, a thermometer and a rimer tou can get some ball park numbers that will give a hint as to how much heat flux you will get with the steel plates.

Above freezing and below boiling water has a linear relationship between heat and temperature.

1 calorie of heat energy will raise 1 gram of water 1 degree centigrade.

Using that relationship you can conduct an experiment to measure the heat flux between the stove and the water.

Measure how much water is in the pot and the starting temp. Put it on the stove and mark the time.

After some time keeping the pot stirred measure the temp and the time.

Calculator the temp change and the amount of time that passed.

Divide the temp change by mass of water to find how many calories went into the water.

Divide the calories by the time to find calories per second. Google will help with unit conversations.

Repeat the test with the steel plates ro see how much the heat flux is reduced.

Ben
 
Little to warm for that test now. lol go figure!
 
Hey @Neb would you think these would be better higher quality modules than the standard TEC1-12706 modules?

https://www.ebay.com/itm/325443696959
I wasn't able to find out much info about them but I've always had excellent service out of Kyocera products. Sure wish I could find the data sheet and temperatures. I talked to the seller and they don't know any more about them than what they have listed.
 
  • Like
Reactions: Neb
I can not hardly believe it's 67 f right now and been in the 60's for a couple days now. Somebody is screwing with the weather. Yeah this is VA and we get weird weather but not this weird.
 
Question for you guys who know a lot more about electronics than I do. Is there a simple way to set a series / parallel switch? These modules are low voltage so I know I will be using 4 or 5 to make 12 volts and 16 to 20 to make 48 volts. What I am wondering is if there is a way I can wire everything up so I can switch between 12 and 48 volts simply? Or even better would be a switch that could let me switch between 12, 24, and 48 volts. Is there a way to make that happen without it becoming more hassle than it's worth?
 
Biggkidd said:
Question for you guys who know a lot more about electronics than I do. Is there a simple way to set a series / parallel switch? These modules are low voltage so I know I will be using 4 or 5 to make 12 volts and 16 to 20 to make 48 volts. What I am wondering is if there is a way I can wire everything up so I can switch between 12 and 48 volts simply? Or even better would be a switch that could let me switch between 12, 24, and 48 volts. Is there a way to make that happen without it becoming more hassle than it's worth?
Click to expand...
Three 4pst switches...

FULL THROTTLE - Heavy Duty 4PST ON-Off Toggle Switch 20A 125V, 15A 250V Screw Terminals (41B) https://a.co/d/bUj8yvb

Can be used if you wire groups of 4 cells in series to each of the poles and are disciplined enough to only enable one switch at a time. Enabling more than one will produce dead shorts... which is bad.

Ben
 
Okay so that is a regular toggle with 4 separate junctions inside making 4 complete but separate circuits with one switch? Or am I reading that wrong?

What you are saying is to use three one for 12V one for 24V and 48V with each voltage wired with the same modules in different combinations for each switch? Sounds like a plate of spaghetti ! Are both positive and negative going through each switch? Leaving each one an open circuit until the switch is closed?
 
You must log in or register to reply here.

Latest posts

Back
Top