Just a quick word about the specific type of Peltier (TEC) device I'm using here: There is no question that there are better (dedicated TEGs) somewhere out there. But the reason why I made this video, is that this specific TEC that is sold as a cooling device is now 4 or 5 euros a piece. During my research I wasn't able to find any cheap dedicated TEGs, but if you know of any please let me know and post a link here if you can.
The peltier has limits. Find those limits. How much heat can it turn to electricity max - And then create a heat pickup that will self-regulate to that power transfer level. You can abuse the laws of physics on differential of expansion of materials. Even a small wax rod will be enough with a spring - if it gets hot, the piston bends the plate and disconnects the bottom heat sink, reducing heat transfer. The cooling side can be designed to cool off within the above spec, passively.
I know as American I probably have better options, but I've been looking into the graphite based superconductor thermal plates. They are far more heat tolerant, and can maximize the differential of hot/cold sides. Try utilizing- the outside sections, double wall pipes, ( I transferred to a square galvanized pipe outside & covered all for sides, wiring then per section, supplying power to battery that power my home.) The middle road higher grade layered graphite/alloy thermal plates are a bit more cost. But You get what you pay for. And Cost efficiency is better than Cheap. Cheap always costs more in long run
Für handy laden und paar leds reicht auch so ein kleines dampfmaschienen model. Da komm ich nämlich zum Punkt. Richtig power würde nämlich ne dampfmachiene bringen. Wenn jetzt son alten rasenmäher motor als dampfmaschiene umbaust. Da machste ein paar ventiele auf und zu um da dampf rein zu lassen und dann lüppt das. Gut da brauchste dann irgendwie ein dampfkessel. ist wieder higher mantinace Aber dann hat man was richtig geiles so.
The big heat sink you kept all this time, reminds me of the definition of "junk": "Junk" is something you hoard and stumble over every day. Then, the DAY AFTER you throw it away, it becomes an irreplaceable item that you really need right now! 😀
You only understand this if a lot of thing that u cared for were trown away :) Thats why I want no significant other, because she might throw my tresures away
I am really heartbroken to see these type of genuine content doesn’t get enough views but useless nonsense get millions of views☹️. Keep up the good work.! Love it
To cool the heat exchange side, move more air across the fins by adding a chimney stack on one side (A). Add a tubular extension to the other. (B) Cooler air drawn in side B by chimney effect of side A. Side B draws cold air from floor. Love your videos. Always makes me think.
This seems like the best way. You can exploit the updraft of the stove to pull cooling air in. I also favor using water as a working fluid with these particular TEGs. A tertiary C-chimney could be used to cool a condenser coil so that the system could use a closed loop of water/steam to heat the TEGs. I would honestly love to see more work done to DIY a simple thermoelectric generator system for powering a marginal computing device similar to the "partisan radio" designs mentioned by Robert Murray-Smith.
I like to use more manual cooling version on a camping setup. Just have other side be warmed by heating water and cool the other plate by placing pot with snow or cool water on top of it. You will need to change the cooling water after a while as it gets warmer. But otherwise it provides a good and controlled thermal gradient which is both safe to the device and close to its max capacity.
@@MOSKAU15 not really a problem as the conductivity with either hot or cold side is good enough so that the side is at the temperature of the water. And peltier works as a heat pump so it tries to equalize all the time against the conductivity.
I've designed campfire equipment that uses peltiers like this and there are a few things you need to consider: First off, you need to read datasheet correctly and datasheets that actually show limits would be useful. The ones you got does not state actual max operating temperature. Normally non high temp TEC is max 138c. Further more there is NO max delta when used as generators, those numbers are for cooling. Secondly, there is actually a fairly large regulation potential in the flow of heat through the TEC by applying a load. The higher the load, the "lower themal resistance" the TEC will appear to have. In essence you can cool the hot side by dumping power into a seperate load if the primary load is not requiring enough current. Lastly, the stove-fans usually use a bimetallic strip under the foot to "lift up" a bit to reduce heat input if the surface is getting too hot. I would suggest creating a fan setup that is adjusted to get max temperature on hot side, and then use fans to cool cold side as much as possible while wasting as little watts as possible. Ideally the power should be stored in a battery using a MPPT control to maximize the power extracted from the TECs.
Yeah that makes more sense. The TEC I looked up on digikey stated "hot side max 80C, solder melting temp 138C/235C" so that must be the limit you are talking about. Maybe best to get the 235C model then? CP60133
Regarding power. It seems these LEDs are constant current. Potentially creating a frequency could 2x or 4x the amount of lights powered as well as additional capacity to dump into a battery or supercap
@@Nihaopaul It doesn't work like that. But something converting voltage/current to ideally load the TEGs at all time would provide more power. Matching the load is very important with TEG. It's almost like a solar cell in that regard.
Using the boiling point of water to limit the temperatures was genius, all you need is a reservoir and remember to keep it filled. Maintaining a heat input that doesn't damage the Peltier modules was essentially the only difficult problem in this project. Good work. It seems that there should be research using the Peltier effect on a larger scale, there are so many industries that produce excess heat which require extensive cooling systems. Recovering even a couple percent of that wasted heat as electricity could be quite significant.
When I was back at university, I had the pleasure of an event lead by professor reiner kümmel. He talked how he had data collected for modelling similar potentials: Using waste heat from on process as input for other processes. Treating waste heat as a resource should be more of a thing. Saw a small documentary on youtube about a factory that thinks heating, cooling and electricity together (and more minor energy savingthat is often dismissed). With energy prices going up at the start of rus invasion of ua, the ROI was 100%, now it's probably dropping down to 30% agai..
this is the working principal behind the RTG's that power space probes. issue being they are very expensive and are at best 5% efficient. assuming the heat is enough to boil water a Rankine cycle steam generator would make the most power but its far larger and more complicated.
@@TittleCreekOutdoors I think you've hit it. A reservoir underneath to limit the hot, steam running to the hot side of the TEG, then through an exchanger to heat the room, draining into an upper reservoir acting as the cold side. An overflow on the cold reservoir drains back into the hot reservoir and bandaging baddaboom you've got it. No mechanical parts, minimal maintenance, probably scalable, renewable heat and power.
There are examples of this type of heat/energy recovery, not usually using Peltie devices, CHP combined heat and power, HVAC often have a heat exchanger between clean intake and dirty outlet.
Hi Tpai, what about having two pipes on the stove? One is an outdoor-air intake pipe and the other is the hot exhaust pipe. You could place the peltier device between the two pipes to maximize the temperature differential. The exhaust pipe would perhaps enter the stove from the top so it is a natural path for rising air while the inlet pipe should feed air from below so it is basically acts like a diode for cold air.
The cold air pipe does not even have to be a stove inlet pipe, simply a duct open to outside would be a much bigger differential than his current setup, PUT A COLD BEER ON TOP, VOILA!
@@Mr.Fabrication007 But why and how would you create wir flow if the pipe simply comes from the outside and goes back to the outside ? This would not make sense, since the stove needs fresh air anyways the idea makes much more sense. You want to reuse the components you already have not intriduce new ones this way you increase the efficiency and decrease part count.
I think he means creating an extra/ separate air intake on the stove at or near the bottom, while still having and rerouting the exhaust pipe. This would solve another issue- the inside of your shop would be much warmer making the stove more wood efficient. Instead of cold air coming in around doors and windows lowering the room temperature, the cold air is confined to the intake. I think you could create another section of square tubing for the intake and have the peltier panels inbetween. This would give you a greater temperature differential, but I’m at a loss how to regulate it. This is a fascinating proof of concept- thanks for so much time and work- making the world a bit better. @@sierraecho884
This is a fantastic proof of concept. I well remember my grandma having a wood stove heating up the kitchen. The exhaust tube had an heat exchanger made of smaller pipes to act as a radiator, and some sticks to suspend washed clothes to dry...
I did little tests with those Peltier modules. The best results I've had generating electricity was having the cool part in water. It helps a lot to keep the modules under safe temperature.
That's what I wanted to propose. He could gravity feed the water to the cool side of the Peltier elements, with a thermostatic valve regulating the outflow, keeping the water temperature at ca. 40 °C. The "spent" cooling water can then sit in a metal container and contribute to room heating (so no energy is lost), and when it is at 20 °C again, maybe the next morning, it can be transferred again to the upper tank of the gravity feed system.
Good job. If you want to generate power from flue gas, you could try constructing a scaled-down version of a waste heat boiler much like is used in the stacks of fired equipment in industrial applications. You would need heat exchanger tubes with high fins within your furnace exhaust ducting which would by thermosyphon circulate to a steam drum. The steam generated could drive a turbine. You would need to add a source of make-up water. Safety considerations include protection against overpressure and vacuum when your system cools and the steam condenses back to water.
I have a biolite stove that generates 10 watts, I use it on camping trips all the time and it works great. It may be worth looking into reverse engineering one of those.
I saw a teardown once. It has a single thermoelectric generator (TEG) element and a battery. The TEG is much more efficient than the peltier elements used by our friend here. They are also much more expensive, somewhere around €50 for a single one. Could however still be more cost efficient than all those easy to break TEC's our friend uses :)
TH-cam is full of demonstrations of Chinese 5kw diesel heaters, but they need a 12v car battery to work. I've been wondering if it would be possible to get enough current from the exhaust gases to charge the battery with a peltier? In the case of off grid, a solar panel is of course the best, but in the north there are a couple of months when you practically don't get solar electricity at all.
@@AH-li7ef There is a TH-camr named David McLuckie who created a working self-powered diesel heater using TEGs and a battery and has several videos on it.
I wanna see a heat exchanger on the stovepipe transport loads of energy from the exhaust into your indoor air via the heatsinks. Maybe the peltier devices could power a pump? Turn this project into a better heating system, rather than a power source.
No. It’s not what you think. All of these forms of power generation are irrelevant if you cannot store energy efficiently and cleaner than our current means of energy supply. If every home in the world required a massive battery to supply consistent energy during hours of non energy generation that would be more toxic than the pollution we currently create. It is an issue of clean storage not clean energy. Most climate freaks don’t understand this.
Dude, this is literally the exact type of technology we need more of, “ doesn’t look like much” looks like a lot to me, getting it more or less correct on the first try is really impressive
Nicely done! Your use of materials salvaged and kept for many years really strikes home. I too find it hard to dispose of many of the items I have collected over the years. Seems like I keep finding a use for those things, if only for experimentation. Please keep up the good work! Good video.
Great video. Those stove top thermoelectric fans are pretty cool. We have heated our house with cordwood for years. During winter we use our cordwood stove to preheat water before it is fed into an electric water heater. I purchased a stainless steel heat exchanger I located in the stove and plumbed it to a salvaged water tank. The two are connected with a passive thermosiphon loop. It turned out to be so effective that I added a pump to circulate water from the electric water heater to the stove tank when the temperature in the stove tanks gets too high. Prior to that on very cold spells the PTRV (pressure temperature relief valve) would dump hot water into a drain wasting my effort.
Any light is good light when the grid goes down. And the square chimney tubes have given me other ideas to draw heat away from chimmey to heat upstairs rooms just by convection and using no electricity at all. Many thanks David in the UK
Some of these fans uses a bimetallic strip on the base to slightly lift the base from the stove top in order to protect the peltier device from high temperatures. I'm sure you can make one by yourself.
Not sure if you are allowed but you can add bricks round your stove to act at heat sink and heat store. Probably won't need to stick them with cement. I believe it will make it more of an effective and efficient shop . I'd add a couple of wind turbines to the roof...I am sure that will another option for power. 😊😊 Love ya from Bedford UK. I know nothing about electrics and would be very much like you given the chance in life.
Just a thought - your biggest temperature differential is going to be when the hot gasses are in the flue outside the building - hot gasses inside the flue, cold air outside the flue. You may even be able to put the peltier directly on the flue outside, and have the surface of the peltier exposed to the air (would depend on how high the temp of the flue was as it exited the building - may need a heatsink/insulation to bring it to 100degrees. But then as the temp outside dropped, the gradient would be bigger? Even at a high external temp, you could always have 100 C + differential between flue temp and ambient air temp. Then it is more like a 'heat recovery' solution - and you could expand the system by lengthening the flue and the number of arrays? Really interesting concept!
great idea, outside is probably way better but the only thing with his pletier is a maximum temp differential it can tolerate, Im sure otherwise he would have done it differently
@@time2fly2124 Until they don't and you have a crater and a hole in the roof, where your boiler was. That's why you have laws for installation and inspection of those systems. Needless complexity. K.I.S.S.
Great video. The stove pipe location was perfect. It also allowed you to use what would normally be wasted. You should add your other left over heat sinks to the other side just to capture more waste heat.
You could add a watertank between the chimney section and the heat sink to make sure you don't get over 100 degrees and still have free airflow over the cold side. The tank could be open top with a simple floater to easily see waterlevel. With the application with off grid cabin you probably want to heat up the space quickly and thereby risk to much heat in the chimney.
Haha, you had the same idea as me at the end of the video, using water to limit the max temperature. I suggest suspending the bottom heat sink up off the pan a little, so if it runs dry it can't transfer (much) heat anymore. You could probably also use some spacers between stove and water bath to avoid boiling it off too fast, since you're seeing >200C on the surface but don't need anywhere near that much. The water bath might require more maintenance, but you're also improving the humidity level in the workshop. Use a large enough bath and keep it just barely at 100C and it could last several days. Just throw a couple handfuls of snow into it every day when you come in. You could also throw the snow on the top heat sink so that it cools it while melting, which would increase power production by increasing the temperature differential. For that matter, a water block on the top heat sink that runs outdoors with a tiny water pump could make a huge improvement in power production.
great concept, I love the way you salvage & re-purpose most of what you need, not very common today but very common in my grandparents day when you repaired not replaced everything & no one could afford to call a repair person so you pretty much needed to learn how everything worked so you could repair it when necessary.
You are a legend sir. Been a fan for years now. You and I have very similar outlooks on life. Hope for the best, plan for the worst and never stop teaching yourself skills.
We bought a home recently with a fireplace and a fire stove. I have been thinking along these lines but this gives me a lot more to consider. I had been thinking of using electric for the than fan, as all i am after is moving more heat around. Thing I did learn is the fireplace insert uses a thermistor to only turn on the fans once it becomes hot enough. A way to leverage this is for aux cooling of this power generator, maybe by enabling additional cooling fans to the heat capture to reduce their temp and not burn up the peltiers. Sounds like a fairly simple idea for someone with your background. The thing would be to be able to over cool for a worst case scenario. Thx for the great ideas!!
I've been thinking of this for years! 💚🇬🇧🌱 After getting my first ecofan, I live on a boat in the UK & this would be great in the winter months when solar is minimal... Interesting🤔
It would be interesting to see if the 300mW fan could be used to cool the upper fins to determine if this would improve power output so there is a net gain.
Use your fans to blow cooler air through top fins to create even more of temperature difference. Bottom fins in hot water limiting and protecting from over heating was a great idea. Good work !
Perhaps you could use pressure from boiling water to lift the device off the surface of the stove. Something like a small hydrolic cylinder could do the trick. Would necessitate some safety measures like an over-pressure relief valve. You could have a steam generator sit directly on the stovetop and dump the steam into the cylinder. The cylinder could then actuate a mechanism to lift the entire assembly off of the surface when the water starts boiling. The assembly should then oscillate between the lowered and raised state, while maintaining a temperature of roughly a hundred degrees C
Some of the stove fans I've used personally have a similar feature. They have a bimetalic strip on the underside with the intention that if the base begins to overheat it is able to lift one side, reducing the contact area and allowing the fan to cool the unit more readily. This is only in theory since I've never got my woodstove hot enough to make the device lift.
Two things that may be possible, a wheel spinning from steam hooked to an alternator or using a sheet of graphene hooked to capacitors to stepup transformers to a buck converter that is made to charge 12 volt batteries. Where an alternator is 13.5 amps, 12 volts DC, 3000 to 6000 watts...
Have you considered trying to experiment with sterling engines? I heard that they can function with higher temperature differentials and are way more effecient, but can be a bit noisy. Still I think it would be cool to see you create one and maybe compare and contrast the different methods of creating power from heat. Keep up the good work!
The water bath idea, gave me an idea. Make a tall pot, like your chiminy mod', and purt the TEC devices on that. The hot simmering water will rise to the top (where you will have mounted the Peltier devices around the square pot), maintaining a high but safe tempreture. But also, as the water boils, the level will fall, reducing the transfer of heat to the devices (fail safe). A shrowd about the heatsinks, will help create a chiminy effect (as mentioned by others), reducig or negating, the need for a fan. Great presentation. I'm always impressed with your skills, innovation, thoughts and results. 👍
I feel like a water cooling system using an old radiator as a reservoir could be quite good for this, it would help rip the heat from the oven and push it into the room as well.
I've seen hundreds of such experiments, in fact there was a team of high school kids who decided to apply these to the exhaust system of vehicles in order to capture what little energy they could. It simply wasn't cost-effective. You really are just better off making steam while gasifying. Keep in mind that all contributions are of value regardless how small so long as they are consistent and of proper duration
Well. When it comes to cost-effective solutions, I already use some rather effective ones (burning free wodd for heat, using solar panels that cost one third when I bought them from what they are now. Battery storage was also free because it was a gift from a sponsor). However, if I would ONLY go for cost-effective solutions this channel would not exist. Almost anything you can think of is either not cost-effective or illegal now. That's why I try to be imaginative when it comes to the situations in which these technologies could be interesting and put more of an emphasis on off-gird ideas, stuff that could work in remote locations or while camping, instead of trying to compete wit the local power company ( which is not going to work in almost all cases)
How about using some large reflectors or fresnal lenses to increase the light intensity and boost the performance of your PV array during the winter months ?
Hi Gerolf, as you mentioned he use of wood gas for power and heating it comes across a subjct I think about recently. Maybe you've seen it before, it's a fairly new type of wood gasifier called the downdraft wood gasifier. It's more compact than Imbert type, produces less tar and prevents some material wear too. The gasification works continously, like some very big carburator. When I find the time I will do some test devices in my workshop that's located some 150 km away from yours.The Hope your surgery did pass well. I since years now extremely dig the approach, the professionatilty and the dedication you put in your work.
I’m think you might need TEG modules instead of TEC? The G is for Generator where the TEC are designed for Cooling like cheaper cool Boxes. It still might be more cost effective using the TEC as last time I looked the TEG module was more expensive. Great videos been watching for many years. Thanks for all your hard work making these videos
Well. The idea for this video came when I realized that a specific type of peltier device has now become very affordable, which is the one I use in this video. I only realized this after watching a video by Tech Ingredients one or two years ago where they used the exact same type of cheap device for power generation. While these devices can be used as TECs or TEGs, I'm certain that there are peltier devices that are much better suited for the operating point and use case I have here, but it isn't really interesting for me or the audience if those devices cost 50 euros instead of 5 euros a piece.
@@Jamey_ETHZurich_TUe_Rulez Absolutely totally wrong. TEG's are much more efficient in generating electricity than TEC's. The principle is the same, but the are built quite differently.
Really good vid, thank you for showing us your development. I did a lot of work with Peltier around 10 years ago as part of a work project. I would be really tempted to actively cool the cold side of the junction to increase the voltage differential. It may use a few Watts but should be worth it. I'd also may consider using a switching regulator to charge up a power bank. This will allow you to run the LEDs at a higher output (granted for a shorter period of time). I would maybe also consider a thermally insulating skirt around the layer of peltiers to prevent the cold side getting heated up as much.
Oh I would actually love to work on something like that. I hace actually read two books that deal with ideas around DIY wood gasification and it is an interesting field. However building something that really works long term is a huge undertaking I'm afraid. It is not exactly 'low maintenance'
@@ThePostApocalypticInventor Take a Look for old, wood-fired Cars. Wenn had a lot here in Germany before world war 1 and after world war 2. My das was born in the "Hunsrück" anc drove some , back in the days, as he was young. :) It's no kind of rocket science. At least, as long as they don't explode ;)
@ThePostApocalypticInventor Is low maintenance a prerequisite of your projects? A 5000 WATT wood power generator would be good. Show off Some stainless steel welding with some electromechanical interlocks a bottleneck design with preheat chamber on a mobile platform that can be towed with a car. This is your mission should you choose to accept it 😊.
My only thought at the end was that you could use a closed loop system with automotive antifreeze and attach the cells to that for the heat. Others are mentioning using cold air from the floor or outside to cool the other side of the cells. If this could all be made compact enough it should be useful! Really appreciate your experiments and that you share with us!
I was also thinking a water loop on the hot side could help, but the problem is the required pump would use more power then you generate using these devices.
excellent project and the same as i am working on. i am trying to source military grade peltier or other heat to power generators....i will let you know. i also use the stove pipe.
The cooling solution could be to add 2 separate peltiers with the fans attached. I'm so glad to see someone actually doing this experiment I've been trying to figure out how to do this myself for 2 years but not experimented.
I honestly think that a video/video series o you fixing your car would be quite interesting, especially with your skill for exaplaining all kinds of systems
I love where you are going with this! I live off grid with solar in Canada and I really would love to employ my wood stove to do more than just heating, cooking, baking and making hot water. I run 2 of those fans but an elegant trickle charging device would really help in the winter. All I want is maximum power from minimal wasted heat.
I would build a heatpipe out of copper tubes used for cryo or air conditioning systems, filled with alcohol or something and attached outside the house, maybe close to the smoke stack. The idea is to remove the heat locally in a way that will not draw too much heat from the inside the room.
One thing you might want to try is a mini fridge that works off of a TEC. The reason is that a mini fridge has a large cooler area that is water tight. You can fill one side with water and it will make a great cooler for the cold side. Then you also get the massive heat sink and fan. This means that you don't need as much heat on the hot side. You can also reverse this by using hot water from your stove. It's pretty much ideal for these projects. I find them used for $8.
I like the way you problem-solve on the fly! Regarding the water-bath option, perhaps use a shallow, sealed oil-bath with clean mineral oil. Using square-section steel with the ends capped, you could eliminate the need for heat sinks on the bottom of the Peltier modules, attaching them directly onto the top surface of the (horizontally oriented) square tube, then concentrate on cooling the top. If the stove was getting to hot, it would be a simple matter to slip something between the stovetop and the bottom of the tube, to provide a little temporary insulation. It might be helpful to install a cheap thermocouple-thermostat onto the bottom (hot) surface, too, so you could have an instant readout on the temperature - attached to an over-temp alarm if desired.
Heat pipes might help you for 1 or both transfers. You could use a steam heat pipe to move a lot of energy a long way from the stove to your modules, and another heat pipe to move a lot of heat from the module a long way into your cold shop
A friend and I did a similar experiment many years ago on his narrowboat. We actively pumped cold canal water through a old CPU watercooling block for the cold side, hot side on the flue of his wood stove with a poor thermal interface. As long as we kept the the whole TEC under 100DegC, the delta acted more like a maximum power output than a limit of destruction - we had 95DegC on the hot side, around 5DegC water, and the power capped out at around that 70DegC delta. We could easily get 0.5w per TEC which isn't a lot of power, but lots of them placed in otherwise unused space like flue, back, and sides of the stove can make a small difference - enough to charge a battery or phone.
Thanks for the video. Just a suggestion, copy the stove fan. On the bottom make a I beam like the fan so the heat can be controlled as it travels up the middle then the Peltier on top then the cooling heat sink.
Hey, I loved your experiments! It's a nice way to reuse waste heat, and can be done in different places around the house. For example, recovering energy from a fridge's condenser, or PC's CPU/GPU cooler.
While it would require a bit of careful welding, a simple cool (room temperature) water tank integrated around your cold side cooling fins would probably be sufficient to maintain your temperature differential. With a good design with perhaps a valve and tube, as the cold side warms up, it could be drained into the (slowly boiling away) hot side, and the cold side topped up with fresh water. As you would have to monitor water levels in your hot side bath anyways, this does not add any real extra maintenance to the system.
Love the project. Very good thoughts! If you had a low-temperature water floor heating, you could use it to cool the cold side of the peltier elements and make for efficient heating of your workshop while generating power. 30°C is typical floor heating water temperature, which leaves you with 70° delta. That's the optimal range of the Peltier elements. Maybe you could even power the pump which circulates the water through your floor heating by the peltier elements. Would make for a independent floor heating system. I liked the idea of the hot-water pot to limit the maximum temperature to keep the Peltier elements safe!
Quick tip: when cutting aluminium with a cut-off saw (and even when sanding with a sanding pad) add a little waste oil. It will prevent blades and pads from clogging and extend their useful life.
Using the stove chimney pipe is a good idea. You could attach your peltier array to hydraulic tubes that would expand or shrink with temperature changes and help keep the peltier array at a more constant temperature.
That's a really great idea, never thought about this application! An interesting improvement would be to add a control loop from cells temperature to a fan. This way you could improve the efficiency
I once built a similar setup, my setup used 10 of those 12706 modules all wired in series. Then i used a cheap solar mppt ~30€ and charged a thrown away car battery with it. I sandwiched the 10 peltiers between 2 aluminium sheets (4 and 5 millimeter). One being the hot side 5mm directly on a stove - the second one being the cold side cooled by water 4mm. Now the cold side being a plain aluminum plate surely isnt ideal but it keeps it cold to the touch. I clamped every peltier between the two plates with 2 screws each. I used thermal compound for maximum heat transfer on both sides. I was able to generate 3W for a short amount of time. Now i can only get a maximum of 1W My design probably failed at thermal expansion. When i first heated it up you could hear it click as it expanded. So you would ideally need: A mppt controller (i dont know if cheap solar works tough) The highest transfer of heat you can manage through the modules. I believe they work up to ~130°C applied on the hot side. The cold side should stay as cold as possible with as little effort as possible. There is no maximum thermal difference (except maybe because of thermal expansion) and as the TECs are intended for cooling this may be more relevant to cooling performance You also need to properly clamp the modules between the plates. There are application guides on the web with pressure values for peltiers which should have been tested. It apparently effects the results by a lot. Meister Jambo made a video on his solution to this problem. Maybe a solution you could try as it seems the least expensive and he also generated high amounts of power with lesser modules. I am looking forward to part 2 and maybe i will revise my design then.
I was thinking of 3 ways to continue the cooling process for the top heatsink: 1. To have a small DC fan on top of the heatsink blowing downwards,that draws power from the Peltier devices. 2. To have the setup on the side of the water bath so that the Peltier fan can be close to it and still touch the surface of the stove. 3. To have an insulated pipe running down vertically from outside that may provide passive cool air flow, placed pointing on top of the top heatsink. Just some ideas that may still need more testing.
One idea like what you made, is to make a standardized section of stove pipe with the peltier generation which could be added to any sort of furnace that uses the standard pipe. A specific application I had in mind is for wood fired, outdoor furnaces. They have a heat exchanger to make hot water which is pumped to radiators in the house. The downside is that there has to be a water pump to move the heated water. I thought it would be great if you could power the pump with thermoelectric generation, so even if the power was out, you could still heat your house. If the stove pipe is outside in the cold, there will be a bigger temperature differential to help make more power.
Love your pipe setup. I would extent the cold-side heat sink all the way down to the floor. To support the weight of the pipe and your generator, and to grab updrafts from the cold floor, to cool the heat sink by natural convection. No cooling fans will be needed.
Ive been using peltiers on my wood burner to power led lighting and fans. Also PTC elements direct from solar, inside sand batteries for storage heaters. Always works well in combination.
lighting alone is a total WIN, before the LED revolution i never realized how important it was because the tech we had sucked so bad...in the early 80s we had a cool device from Coleman that ran on fuel to power a fiberglass filamented lamp, it was insanely bright and made a buzzing sound while it ran...
You might be able to pull in cold air from the outside and cool the cold side. The stove should create a negative pressure in the room. Thanks for a fun experiment!
SO many questions. So many ideas. I've been thinking about this exact experiment for years. Since so much heat is wasted through the vent, we can assume that all of that heat is harvestable. So, it doesn't make sense to just carry it away in one pipe. Why not a manifold that would separate the hot air into several pipes, or more simply, imagine a "pipe" that is 3 feet by 3 feet by 1" thick. It's basically a big 1" thick hollow box, with an adapter at the top and bottom to exhaust out the 6" pipe fitting or whatever it is. Now cut a square hole in the box. Leaving a 1" lip all around the front surface. Now you create a massive 3' by 3' door that can be screwed on and is sealed with exhaust gas silicon rubber. This "door" or panel cover is the platform, for the peltiers and heat sinks on the front. On the back of the door , you have fins going vertically, to guide the air from the bottom to the top for even distribution. Should cleaning ever be needed because of inefficient combustion, this "door" can be unscrewed and removed. Now all that would be enough if you wanted to stop there, because we could use convection to keep the hot side hot and the cold side cold, but lets say we went crazy, and created a second unit. The exact same size and shape. But, instead of putting it on the front, we flip the whole thing around, and now all the heat sinks are joined into one massive heat sink block, pressed against the wall, taking advantage of the thermal mass of the wall, for cooling, and instead of the bottom opening of the sink block taking in hot exhaust air, it takes in cool air from the ground, and even the ambient heat from the stove itself isn't rising directly into your heat sinks convection flow. Since you're in here already, take some of that energy for a single fan to force the cool ground air into the cooling block, just as a test to see if it increases efficiency or if it uses more power than it adds t the system. . At the top of the cooling block exhaust the now warmer air into the room. Of course with this method you could go insane attaching more and more peltiers to the ever cooling "cold" side air all over the room if you want. Since this heat exchanger doesn't carry any of the combustible gasses with it but let's not go there unless you want to make a really weird fun video. :)
This is fantastic. A few other engineers have tinkered with these devices to mixed results, overheating is an issue on the hot side across all experiments I have seen. possible solution might be to have one of those fans kick on at a critical time to bring the hot side back down. Perhaps a greater thermal mass to leach the heat/power from. Water is a great heat sink, adding an upside down bottle will allow it to self refill as it evaporates. Copper thermal tubes are a great, non mechanical, cooling devices that could be used in the system. OR not sealing the chimney square tube but allowing some air to travel through it will let it convect some air the hotter it gets, a manual baffle would allow you to dial it in. Just thoughts, the balance is between generating the right amount of heat on a wood stove and that is a tricky thing as the heating cooling cycle is very radical. Stability and repeatability will allow you to add longevity to the delicate electronics. Wood gas is an exciting idea but the reactor needed to do it would require a complete rework of that stove and would be more easily accomplish by finding compressor tanks or such in the scrap yard and starting from scratch, but also I think it is a worth while endeavor as the wood you collect is cheap, shelf stable fuel source, and a cabin in the woods will have access to this fuel. Look into 'little aussie rockets' and kick around the idea of a rocket stove build if the shop stove needs a redesign. Thank you for uploading this video. It made my day just seeing the thumb nail. Now I have to go, there are some wood crates to collect from the dumpsters at work, might come in handy for something.
I used power and peltiers and water cooling to cool drinks quickly, so it's almost the same ;) Great video, what an amazing though to capture all of the wasted energy everywhere.
Food for thought, sir. It is the very edge of efficiency and I hope you get the power back or saved from what was used to build the devices. You have better 'hands on' experience. All the best Gerolf. Cheers!
The TEG is a wonderful piece of history, and it works. All you need to do for the boiling water one is to set up a thermal siphon. Advantages are no moving parts, and it can help spread the heat from the wood stove.
Laptop computers typically use heat pipes to conduct the heat away. You might try a few of them on the cool side of your device. Thanks for another great video!
Like the concept of a ‘smart flue’ but rather than lighting just some basic digital info like temperature, burn duration etc? Perhaps a usb out for another fan? Great idea!
Submerging the hot side in boiling water to stop overheating is brilliant, but keep in mind that thin pieces of metal like fins can also act as thermal brakes. Also if you put a water heat exchanger on the hot side, you do not need a pump. If you place the hot outlet above the cold inlet heat convection will act as a natural pump pulling in cool water as hot water rises.
In UK, similar stovetop fans comes with a bimetalic strip on the bottom than can rise it a little and prevent it form getting damaged. Big Clive have a video about it.
Interesting to see this, a company I'm working for is experimenting using peltier units to harvest energy from the condenser on a cryogenic system. Same issues but the differential is derived from cold (-170ºC).
2:27 one of the core concepts of improving tech is to figure out the principles behind it. For electric, it’s like making a contained liquid system move externally. Coils are used to pickup as much energy influence as possible. There’s other ways to influence electrons to start flowing. Different metals for example have thermal properties, others have different effects on temperature.
I love this idea! Adding active stuff is to be avoided - I totally love the idea of a passive power generator / light / fan from a wood fire! With a few more watts I could power a phone from a campfire!
Great Project! Have thought about similar stuff a coupe of years ago. Getting the heat out of the system is a pain in the ***, but transporting heat is quite easy. so I would work with steam, like a couple of others have suggested. Pipe the steam outside to a condenser where you mount the peltier elements. It also has the advantage of getting the elements away from the stove. Get yourself a big cooking pot (maybe a pressure cooker, so you can experiment), mount a hose stem, connect an isolated pipe with a steam hose and than the condenser. For the condenser I would go with a perforated pipe inside of a square tube. Mount the elements on the outside and you have enough room to run wires for each element along the edges which should improve troubleshooting. use metal sheets for heat dissipation, cut it in an angle to create fins that point upward for a more uniform dissipation, than bent the fins in different U shapes. For a prototype I wouldn't bother with a return pipe. Also: I wouldn't use the exhaust pipe, there could be a danger of creosol condensation and a chimney fire. Grüße ausm Pott
To get a source of cooling: Make an outside combustion air feed to the stove thru a 3" or so pipe, as the stove draws in outside COLD winter air, direct it thru the heat sink on the cool side. This will supercool the devices and possibly prevent hot side damage. It would also up your heating capacity by reducing the infiltration of cooling air to the living space. Michael in Colorado.
Outstanding idea! I often wonder if you could generate power using weights just like in a clock movement. Because gravity is something that will never go away and everyone has it.
Just a quick word about the specific type of Peltier (TEC) device I'm using here: There is no question that there are better (dedicated TEGs) somewhere out there. But the reason why I made this video, is that this specific TEC that is sold as a cooling device is now 4 or 5 euros a piece. During my research I wasn't able to find any cheap dedicated TEGs, but if you know of any please let me know and post a link here if you can.
The peltier has limits. Find those limits. How much heat can it turn to electricity max - And then create a heat pickup that will self-regulate to that power transfer level. You can abuse the laws of physics on differential of expansion of materials. Even a small wax rod will be enough with a spring - if it gets hot, the piston bends the plate and disconnects the bottom heat sink, reducing heat transfer. The cooling side can be designed to cool off within the above spec, passively.
I know as American I probably have better options, but I've been looking into the graphite based superconductor thermal plates. They are far more heat tolerant, and can maximize the differential of hot/cold sides. Try utilizing- the outside sections, double wall pipes, ( I transferred to a square galvanized pipe outside & covered all for sides, wiring then per section, supplying power to battery that power my home.) The middle road higher grade layered graphite/alloy thermal plates are a bit more cost. But You get what you pay for. And Cost efficiency is better than Cheap. Cheap always costs more in long run
if you heat up peltier coller to slow petier coler can't produce electricity an can burned off
have you thought about stirling engines?
Für handy laden und paar leds reicht auch so ein kleines dampfmaschienen model. Da komm ich nämlich zum Punkt. Richtig power würde nämlich ne dampfmachiene bringen. Wenn jetzt son alten rasenmäher motor als dampfmaschiene umbaust. Da machste ein paar ventiele auf und zu um da dampf rein zu lassen und dann lüppt das. Gut da brauchste dann irgendwie ein dampfkessel. ist wieder higher mantinace Aber dann hat man was richtig geiles so.
The big heat sink you kept all this time, reminds me of the definition of "junk": "Junk" is something you hoard and stumble over every day. Then, the DAY AFTER you throw it away, it becomes an irreplaceable item that you really need right now! 😀
I would only add to the definition, the DAY AFTER my wife throws it out….
My exact experience!! (Not corncerning my better half, not that)
Same, hubby throws it out 😂
You only understand this if a lot of thing that u cared for were trown away :)
Thats why I want no significant other, because she might throw my tresures away
I have named the phnomena "hoarder's despair", however, when you find the use before throwing it out it's "hoarder's delight".
I am really heartbroken to see these type of genuine content doesn’t get enough views but useless nonsense get millions of views☹️. Keep up the good work.! Love it
To cool the heat exchange side, move more air across the fins by adding a chimney stack on one side (A). Add a tubular extension to the other. (B) Cooler air drawn in side B by chimney effect of side A. Side B draws cold air from floor. Love your videos. Always makes me think.
This seems like the best way. You can exploit the updraft of the stove to pull cooling air in. I also favor using water as a working fluid with these particular TEGs. A tertiary C-chimney could be used to cool a condenser coil so that the system could use a closed loop of water/steam to heat the TEGs.
I would honestly love to see more work done to DIY a simple thermoelectric generator system for powering a marginal computing device similar to the "partisan radio" designs mentioned by Robert Murray-Smith.
yeah take advantage of the convection. A differential already exists in the room, make that your friend @@bearnaff9387
I like to use more manual cooling version on a camping setup. Just have other side be warmed by heating water and cool the other plate by placing pot with snow or cool water on top of it. You will need to change the cooling water after a while as it gets warmer. But otherwise it provides a good and controlled thermal gradient which is both safe to the device and close to its max capacity.
Seems like good idea, problem would be to not exceed the 70°C difference between hot and cold side
@@MOSKAU15 not really a problem as the conductivity with either hot or cold side is good enough so that the side is at the temperature of the water. And peltier works as a heat pump so it tries to equalize all the time against the conductivity.
I've designed campfire equipment that uses peltiers like this and there are a few things you need to consider:
First off, you need to read datasheet correctly and datasheets that actually show limits would be useful. The ones you got does not state actual max operating temperature. Normally non high temp TEC is max 138c. Further more there is NO max delta when used as generators, those numbers are for cooling.
Secondly, there is actually a fairly large regulation potential in the flow of heat through the TEC by applying a load. The higher the load, the "lower themal resistance" the TEC will appear to have. In essence you can cool the hot side by dumping power into a seperate load if the primary load is not requiring enough current.
Lastly, the stove-fans usually use a bimetallic strip under the foot to "lift up" a bit to reduce heat input if the surface is getting too hot.
I would suggest creating a fan setup that is adjusted to get max temperature on hot side, and then use fans to cool cold side as much as possible while wasting as little watts as possible. Ideally the power should be stored in a battery using a MPPT control to maximize the power extracted from the TECs.
Yeah that makes more sense. The TEC I looked up on digikey stated "hot side max 80C, solder melting temp 138C/235C" so that must be the limit you are talking about. Maybe best to get the 235C model then? CP60133
Regarding power. It seems these LEDs are constant current. Potentially creating a frequency could 2x or 4x the amount of lights powered as well as additional capacity to dump into a battery or supercap
Good points
@@Nihaopaul It doesn't work like that. But something converting voltage/current to ideally load the TEGs at all time would provide more power. Matching the load is very important with TEG. It's almost like a solar cell in that regard.
peltier elements are hugely inefficient. they experiment is doomed to failure before he starts to think about it.
Using the boiling point of water to limit the temperatures was genius, all you need is a reservoir and remember to keep it filled. Maintaining a heat input that doesn't damage the Peltier modules was essentially the only difficult problem in this project. Good work. It seems that there should be research using the Peltier effect on a larger scale, there are so many industries that produce excess heat which require extensive cooling systems. Recovering even a couple percent of that wasted heat as electricity could be quite significant.
When I was back at university, I had the pleasure of an event lead by professor reiner kümmel. He talked how he had data collected for modelling similar potentials: Using waste heat from on process as input for other processes. Treating waste heat as a resource should be more of a thing. Saw a small documentary on youtube about a factory that thinks heating, cooling and electricity together (and more minor energy savingthat is often dismissed). With energy prices going up at the start of rus invasion of ua, the ROI was 100%, now it's probably dropping down to 30% agai..
He could probably put the reservoir on top of the heat sink to act as a cooler.
this is the working principal behind the RTG's that power space probes. issue being they are very expensive and are at best 5% efficient. assuming the heat is enough to boil water a Rankine cycle steam generator would make the most power but its far larger and more complicated.
@@TittleCreekOutdoors I think you've hit it. A reservoir underneath to limit the hot, steam running to the hot side of the TEG, then through an exchanger to heat the room, draining into an upper reservoir acting as the cold side. An overflow on the cold reservoir drains back into the hot reservoir and bandaging baddaboom you've got it. No mechanical parts, minimal maintenance, probably scalable, renewable heat and power.
There are examples of this type of heat/energy recovery, not usually using Peltie devices, CHP combined heat and power, HVAC often have a heat exchanger between clean intake and dirty outlet.
Hi Tpai, what about having two pipes on the stove? One is an outdoor-air intake pipe and the other is the hot exhaust pipe. You could place the peltier device between the two pipes to maximize the temperature differential. The exhaust pipe would perhaps enter the stove from the top so it is a natural path for rising air while the inlet pipe should feed air from below so it is basically acts like a diode for cold air.
BRILLIANT!! Vote this up!
Yes, good idea.
The cold air pipe does not even have to be a stove inlet pipe, simply a duct open to outside would be a much bigger differential than his current setup, PUT A COLD BEER ON TOP, VOILA!
@@Mr.Fabrication007 But why and how would you create wir flow if the pipe simply comes from the outside and goes back to the outside ? This would not make sense, since the stove needs fresh air anyways the idea makes much more sense. You want to reuse the components you already have not intriduce new ones this way you increase the efficiency and decrease part count.
I think he means creating an extra/ separate air intake on the stove at or near the bottom, while still having and rerouting the exhaust pipe. This would solve another issue- the inside of your shop would be much warmer making the stove more wood efficient. Instead of cold air coming in around doors and windows lowering the room temperature, the cold air is confined to the intake. I think you could create another section of square tubing for the intake and have the peltier panels inbetween. This would give you a greater temperature differential, but I’m at a loss how to regulate it. This is a fascinating proof of concept- thanks for so much time and work- making the world a bit better. @@sierraecho884
This is a fantastic proof of concept. I well remember my grandma having a wood stove heating up the kitchen. The exhaust tube had an heat exchanger made of smaller pipes to act as a radiator, and some sticks to suspend washed clothes to dry...
Goodness, you're not messing around! Using quite some material, building decently sized prototypes, then moving on. Mad respect.
I did little tests with those Peltier modules. The best results I've had generating electricity was having the cool part in water. It helps a lot to keep the modules under safe temperature.
That's what I wanted to propose. He could gravity feed the water to the cool side of the Peltier elements, with a thermostatic valve regulating the outflow, keeping the water temperature at ca. 40 °C. The "spent" cooling water can then sit in a metal container and contribute to room heating (so no energy is lost), and when it is at 20 °C again, maybe the next morning, it can be transferred again to the upper tank of the gravity feed system.
Good job. If you want to generate power from flue gas, you could try constructing a scaled-down version of a waste heat boiler much like is used in the stacks of fired equipment in industrial applications. You would need heat exchanger tubes with high fins within your furnace exhaust ducting which would by thermosyphon circulate to a steam drum. The steam generated could drive a turbine. You would need to add a source of make-up water. Safety considerations include protection against overpressure and vacuum when your system cools and the steam condenses back to water.
I have a biolite stove that generates 10 watts, I use it on camping trips all the time and it works great. It may be worth looking into reverse engineering one of those.
I saw a teardown once. It has a single thermoelectric generator (TEG) element and a battery. The TEG is much more efficient than the peltier elements used by our friend here. They are also much more expensive, somewhere around €50 for a single one. Could however still be more cost efficient than all those easy to break TEC's our friend uses :)
I also own a Biolight stove, and it’s amazing! Have had it for 5-6 years I think, and it works as good now as it did when it was new. 👍😀
Biolite doesn't generate 10W it only claims to generate 3W peak.
TH-cam is full of demonstrations of Chinese 5kw diesel heaters, but they need a 12v car battery to work. I've been wondering if it would be possible to get enough current from the exhaust gases to charge the battery with a peltier? In the case of off grid, a solar panel is of course the best, but in the north there are a couple of months when you practically don't get solar electricity at all.
@@AH-li7ef There is a TH-camr named David McLuckie who created a working self-powered diesel heater using TEGs and a battery and has several videos on it.
We need this man to reconstruct society from scratch
Please, no.
I'm afraid this society isn't worth being reconstructed@@Sixta16
I wanna see a heat exchanger on the stovepipe transport loads of energy from the exhaust into your indoor air via the heatsinks. Maybe the peltier devices could power a pump? Turn this project into a better heating system, rather than a power source.
@@ThePostApocalypticInventor always keep the hope. Just remember that you can’t fix stupid 😂
No. It’s not what you think. All of these forms of power generation are irrelevant if you cannot store energy efficiently and cleaner than our current means of energy supply. If every home in the world required a massive battery to supply consistent energy during hours of non energy generation that would be more toxic than the pollution we currently create. It is an issue of clean storage not clean energy. Most climate freaks don’t understand this.
Dude, this is literally the exact type of technology we need more of, “ doesn’t look like much” looks like a lot to me, getting it more or less correct on the first try is really impressive
What do you mean more of? Pettier devices have been around for decade. They’re in allsorts of devices.
Nicely done! Your use of materials salvaged and kept for many years really strikes home. I too find it hard to dispose of many of the items I have collected over the years. Seems like I keep finding a use for those things, if only for experimentation. Please keep up the good work! Good video.
Great video. Those stove top thermoelectric fans are pretty cool. We have heated our house with cordwood for years. During winter we use our cordwood stove to preheat water before it is fed into an electric water heater. I purchased a stainless steel heat exchanger I located in the stove and plumbed it to a salvaged water tank. The two are connected with a passive thermosiphon loop. It turned out to be so effective that I added a pump to circulate water from the electric water heater to the stove tank when the temperature in the stove tanks gets too high. Prior to that on very cold spells the PTRV (pressure temperature relief valve) would dump hot water into a drain wasting my effort.
Any light is good light when the grid goes down. And the square chimney tubes have given me other ideas to draw heat away from chimmey to heat upstairs rooms just by convection and using no electricity at all.
Many thanks
David in the UK
Some of these fans uses a bimetallic strip on the base to slightly lift the base from the stove top in order to protect the peltier device from high temperatures. I'm sure you can make one by yourself.
...or the wax thermostatic element from a car coolant system.
@@imwacc0834 car coolant wax wt?? car cooling systems do not have any wax parts
@@Mr.Fabrication007yes they do. The automotive thermostat is opened by a wax motor.
Fellow, I appreciate all that you are doing and feel for you guys over there.
Not sure if you are allowed but you can add bricks round your stove to act at heat sink and heat store. Probably won't need to stick them with cement. I believe it will make it more of an effective and efficient shop . I'd add a couple of wind turbines to the roof...I am sure that will another option for power. 😊😊 Love ya from Bedford UK. I know nothing about electrics and would be very much like you given the chance in life.
Just a thought - your biggest temperature differential is going to be when the hot gasses are in the flue outside the building - hot gasses inside the flue, cold air outside the flue.
You may even be able to put the peltier directly on the flue outside, and have the surface of the peltier exposed to the air (would depend on how high the temp of the flue was as it exited the building - may need a heatsink/insulation to bring it to 100degrees.
But then as the temp outside dropped, the gradient would be bigger?
Even at a high external temp, you could always have 100 C + differential between flue temp and ambient air temp.
Then it is more like a 'heat recovery' solution - and you could expand the system by lengthening the flue and the number of arrays?
Really interesting concept!
great idea, outside is probably way better but the only thing with his pletier is a maximum temp differential it can tolerate, Im sure otherwise he would have done it differently
A steam engine generator may be fun to experiment with too. Thanks for the great video!
probably would generate more energy also. we've been using steam engines for over 200 years and we know they work!
@@time2fly2124 Until they don't and you have a crater and a hole in the roof, where your boiler was. That's why you have laws for installation and inspection of those systems. Needless complexity. K.I.S.S.
Great video. The stove pipe location was perfect. It also allowed you to use what would normally be wasted. You should add your other left over heat sinks to the other side just to capture more waste heat.
You could add a watertank between the chimney section and the heat sink to make sure you don't get over 100 degrees and still have free airflow over the cold side. The tank could be open top with a simple floater to easily see waterlevel. With the application with off grid cabin you probably want to heat up the space quickly and thereby risk to much heat in the chimney.
Haha, you had the same idea as me at the end of the video, using water to limit the max temperature. I suggest suspending the bottom heat sink up off the pan a little, so if it runs dry it can't transfer (much) heat anymore. You could probably also use some spacers between stove and water bath to avoid boiling it off too fast, since you're seeing >200C on the surface but don't need anywhere near that much.
The water bath might require more maintenance, but you're also improving the humidity level in the workshop. Use a large enough bath and keep it just barely at 100C and it could last several days. Just throw a couple handfuls of snow into it every day when you come in. You could also throw the snow on the top heat sink so that it cools it while melting, which would increase power production by increasing the temperature differential. For that matter, a water block on the top heat sink that runs outdoors with a tiny water pump could make a huge improvement in power production.
Excellent video.
What about a Stirling engine generator?
Moving parts
@@davidcoates4852solid state
@@davidcoates4852 Technically everything has moving parts, even peltiers... i.e. electrons
great concept, I love the way you salvage & re-purpose most of what you need, not very common today but very common in my grandparents day when you repaired not replaced everything & no one could afford to call a repair person so you pretty much needed to learn how everything worked so you could repair it when necessary.
Immer wieder faszinierend, wie du dich in diese Materie hinein denken kannst. Allet Jute.
You are a legend sir. Been a fan for years now. You and I have very similar outlooks on life. Hope for the best, plan for the worst and never stop teaching yourself skills.
We bought a home recently with a fireplace and a fire stove. I have been thinking along these lines but this gives me a lot more to consider. I had been thinking of using electric for the than fan, as all i am after is moving more heat around. Thing I did learn is the fireplace insert uses a thermistor to only turn on the fans once it becomes hot enough. A way to leverage this is for aux cooling of this power generator, maybe by enabling additional cooling fans to the heat capture to reduce their temp and not burn up the peltiers. Sounds like a fairly simple idea for someone with your background. The thing would be to be able to over cool for a worst case scenario.
Thx for the great ideas!!
You're the last real tinkering inventor on yt. Enjoy every last of your videos.
agreed on that for sure
You really think so? Not even Matthias Wandel? He always seems to be tinkering and inventing...
@@pete3897 He has a different style of content tbh
defn a amazing channel also though
What a load of BS.
There are soo many "real tinkering inventors". Why would you say such obvious false things?
I've been thinking of this for years! 💚🇬🇧🌱 After getting my first ecofan, I live on a boat in the UK & this would be great in the winter months when solar is minimal... Interesting🤔
It would be interesting to see if the 300mW fan could be used to cool the upper fins to determine if this would improve power output so there is a net gain.
Use your fans to blow cooler air through top fins to create even more of temperature difference. Bottom fins in hot water limiting and protecting from over heating was a great idea. Good work !
Perhaps you could use pressure from boiling water to lift the device off the surface of the stove. Something like a small hydrolic cylinder could do the trick.
Would necessitate some safety measures like an over-pressure relief valve.
You could have a steam generator sit directly on the stovetop and dump the steam into the cylinder. The cylinder could then actuate a mechanism to lift the entire assembly off of the surface when the water starts boiling. The assembly should then oscillate between the lowered and raised state, while maintaining a temperature of roughly a hundred degrees C
Some of the stove fans I've used personally have a similar feature. They have a bimetalic strip on the underside with the intention that if the base begins to overheat it is able to lift one side, reducing the contact area and allowing the fan to cool the unit more readily. This is only in theory since I've never got my woodstove hot enough to make the device lift.
Two things that may be possible, a wheel spinning from steam hooked to an alternator or using a sheet of graphene hooked to capacitors to stepup transformers to a buck converter that is made to charge 12 volt batteries. Where an alternator is 13.5 amps, 12 volts DC, 3000 to 6000 watts...
Have you considered trying to experiment with sterling engines? I heard that they can function with higher temperature differentials and are way more effecient, but can be a bit noisy. Still I think it would be cool to see you create one and maybe compare and contrast the different methods of creating power from heat. Keep up the good work!
The water bath idea, gave me an idea. Make a tall pot, like your chiminy mod', and purt the TEC devices on that. The hot simmering water will rise to the top (where you will have mounted the Peltier devices around the square pot), maintaining a high but safe tempreture. But also, as the water boils, the level will fall, reducing the transfer of heat to the devices (fail safe).
A shrowd about the heatsinks, will help create a chiminy effect (as mentioned by others), reducig or negating, the need for a fan.
Great presentation. I'm always impressed with your skills, innovation, thoughts and results.
👍
How about using sand as a heat source (I understand it holds heat much longer) and a water cooling system on the cooling side?
I feel like a water cooling system using an old radiator as a reservoir could be quite good for this, it would help rip the heat from the oven and push it into the room as well.
Boiling water and sending it at a homemade tesla turbine with a brushless motor on it would give some serious power enough to run the gaff
So serious, it could probably make couple W with the efficiency of this TEG.
A creative man from a great country
I've seen hundreds of such experiments, in fact there was a team of high school kids who decided to apply these to the exhaust system of vehicles in order to capture what little energy they could.
It simply wasn't cost-effective.
You really are just better off making steam while gasifying.
Keep in mind that all contributions are of value regardless how small so long as they are consistent and of proper duration
Well. When it comes to cost-effective solutions, I already use some rather effective ones (burning free wodd for heat, using solar panels that cost one third when I bought them from what they are now. Battery storage was also free because it was a gift from a sponsor). However, if I would ONLY go for cost-effective solutions this channel would not exist. Almost anything you can think of is either not cost-effective or illegal now. That's why I try to be imaginative when it comes to the situations in which these technologies could be interesting and put more of an emphasis on off-gird ideas, stuff that could work in remote locations or while camping, instead of trying to compete wit the local power company ( which is not going to work in almost all cases)
How about using some large reflectors or fresnal lenses to increase the light intensity and boost the performance of your PV array during the winter months ?
Hi Gerolf,
as you mentioned he use of wood gas for power and heating it comes across a subjct I think about recently.
Maybe you've seen it before, it's a fairly new type of wood gasifier called the downdraft wood gasifier.
It's more compact than Imbert type, produces less tar and prevents some material wear too.
The gasification works continously, like some very big carburator.
When I find the time I will do some test devices in my workshop that's located some 150 km away from yours.The
Hope your surgery did pass well.
I since years now extremely dig the approach, the professionatilty and the dedication you put in your work.
I’m think you might need TEG modules instead of TEC? The G is for Generator where the TEC are designed for Cooling like cheaper cool Boxes. It still might be more cost effective using the TEC as last time I looked the TEG module was more expensive. Great videos been watching for many years. Thanks for all your hard work making these videos
They are absolutelly, totally same thing just work in reverse. They just write something else on sticker.
Well. The idea for this video came when I realized that a specific type of peltier device has now become very affordable, which is the one I use in this video. I only realized this after watching a video by Tech Ingredients one or two years ago where they used the exact same type of cheap device for power generation. While these devices can be used as TECs or TEGs, I'm certain that there are peltier devices that are much better suited for the operating point and use case I have here, but it isn't really interesting for me or the audience if those devices cost 50 euros instead of 5 euros a piece.
@@Jamey_ETHZurich_TUe_Rulez Absolutely totally wrong. TEG's are much more efficient in generating electricity than TEC's. The principle is the same, but the are built quite differently.
Really good vid, thank you for showing us your development. I did a lot of work with Peltier around 10 years ago as part of a work project. I would be really tempted to actively cool the cold side of the junction to increase the voltage differential. It may use a few Watts but should be worth it. I'd also may consider using a switching regulator to charge up a power bank. This will allow you to run the LEDs at a higher output (granted for a shorter period of time). I would maybe also consider a thermally insulating skirt around the layer of peltiers to prevent the cold side getting heated up as much.
Instead of Pelletier elements, I would prefer a woodgas powered power generator
Oh I would actually love to work on something like that. I hace actually read two books that deal with ideas around DIY wood gasification and it is an interesting field. However building something that really works long term is a huge undertaking I'm afraid. It is not exactly 'low maintenance'
@@ThePostApocalypticInventor Take a Look for old, wood-fired Cars.
Wenn had a lot here in Germany before world war 1 and after world war 2.
My das was born in the "Hunsrück" anc drove some , back in the days, as he was young. :)
It's no kind of rocket science.
At least, as long as they don't explode ;)
@ThePostApocalypticInventor Is low maintenance a prerequisite of your projects? A 5000 WATT wood power generator would be good. Show off Some stainless steel welding with some electromechanical interlocks a bottleneck design with preheat chamber on a mobile platform that can be towed with a car. This is your mission should you choose to accept it 😊.
My only thought at the end was that you could use a closed loop system with automotive antifreeze and attach the cells to that for the heat. Others are mentioning using cold air from the floor or outside to cool the other side of the cells. If this could all be made compact enough it should be useful! Really appreciate your experiments and that you share with us!
I was also thinking a water loop on the hot side could help, but the problem is the required pump would use more power then you generate using these devices.
You could probably sell this to the Democrats as Green Tech & get Carbon Credits for it.
excellent project and the same as i am working on. i am trying to source military grade peltier or other heat to power generators....i will let you know. i also use the stove pipe.
I have had lots of ideas for peltier devices over the years, but never actually made a prototype. You are living my dreams! 👍😀😎
I played around with something like this a few years ago, I think you just encouraged me to revisit the project.
this is revolutionary for people in remote areas!
The cooling solution could be to add 2 separate peltiers with the fans attached.
I'm so glad to see someone actually doing this experiment I've been trying to figure out how to do this myself for 2 years but not experimented.
I honestly think that a video/video series o you fixing your car would be quite interesting, especially with your skill for exaplaining all kinds of systems
I love where you are going with this! I live off grid with solar in Canada and I really would love to employ my wood stove to do more than just heating, cooking, baking and making hot water. I run 2 of those fans but an elegant trickle charging device would really help in the winter. All I want is maximum power from minimal wasted heat.
This would be perfect for a hot tent. I'm super fascinated by the peltier fans too. Great video & proof of concept
I would build a heatpipe out of copper tubes used for cryo or air conditioning systems, filled with alcohol or something and attached outside the house, maybe close to the smoke stack. The idea is to remove the heat locally in a way that will not draw too much heat from the inside the room.
I need this for lighting the sauna & stove I built in my latest video! Thanks for sharing your experiments!
One thing you might want to try is a mini fridge that works off of a TEC. The reason is that a mini fridge has a large cooler area that is water tight. You can fill one side with water and it will make a great cooler for the cold side. Then you also get the massive heat sink and fan. This means that you don't need as much heat on the hot side. You can also reverse this by using hot water from your stove. It's pretty much ideal for these projects. I find them used for $8.
I like the way you problem-solve on the fly!
Regarding the water-bath option, perhaps use a shallow, sealed oil-bath with clean mineral oil.
Using square-section steel with the ends capped, you could eliminate the need for heat sinks on the bottom of the Peltier modules, attaching them directly onto the top surface of the (horizontally oriented) square tube, then concentrate on cooling the top.
If the stove was getting to hot, it would be a simple matter to slip something between the stovetop and the bottom of the tube, to provide a little temporary insulation.
It might be helpful to install a cheap thermocouple-thermostat onto the bottom (hot) surface, too, so you could have an instant readout on the temperature - attached to an over-temp alarm if desired.
Ive wanted to try this for years but just never did it. Im glad to see someone give it a try and see that it is successful
Heat pipes might help you for 1 or both transfers. You could use a steam heat pipe to move a lot of energy a long way from the stove to your modules, and another heat pipe to move a lot of heat from the module a long way into your cold shop
i love those antique peltier fans, especially the ones with bimetalic parts to switch them on or off. they make a huge difference!
A friend and I did a similar experiment many years ago on his narrowboat. We actively pumped cold canal water through a old CPU watercooling block for the cold side, hot side on the flue of his wood stove with a poor thermal interface. As long as we kept the the whole TEC under 100DegC, the delta acted more like a maximum power output than a limit of destruction - we had 95DegC on the hot side, around 5DegC water, and the power capped out at around that 70DegC delta. We could easily get 0.5w per TEC which isn't a lot of power, but lots of them placed in otherwise unused space like flue, back, and sides of the stove can make a small difference - enough to charge a battery or phone.
Thanks for the video.
Just a suggestion, copy the stove fan. On the bottom make a I beam like the fan so the heat can be controlled as it travels up the middle then the Peltier on top then the cooling heat sink.
Hey, I loved your experiments! It's a nice way to reuse waste heat, and can be done in different places around the house. For example, recovering energy from a fridge's condenser, or PC's CPU/GPU cooler.
While it would require a bit of careful welding, a simple cool (room temperature) water tank integrated around your cold side cooling fins would probably be sufficient to maintain your temperature differential. With a good design with perhaps a valve and tube, as the cold side warms up, it could be drained into the (slowly boiling away) hot side, and the cold side topped up with fresh water.
As you would have to monitor water levels in your hot side bath anyways, this does not add any real extra maintenance to the system.
Love the project. Very good thoughts! If you had a low-temperature water floor heating, you could use it to cool the cold side of the peltier elements and make for efficient heating of your workshop while generating power. 30°C is typical floor heating water temperature, which leaves you with 70° delta. That's the optimal range of the Peltier elements. Maybe you could even power the pump which circulates the water through your floor heating by the peltier elements. Would make for a independent floor heating system. I liked the idea of the hot-water pot to limit the maximum temperature to keep the Peltier elements safe!
Quick tip: when cutting aluminium with a cut-off saw (and even when sanding with a sanding pad) add a little waste oil. It will prevent blades and pads from clogging and extend their useful life.
A great experimental project! Maybe add a water loop thermosyphon on the side of the woodstove and connect it to a water tank for hot water as well!
Using the stove chimney pipe is a good idea. You could attach your peltier array to hydraulic tubes that would expand or shrink with temperature changes and help keep the peltier array at a more constant temperature.
That's a really great idea, never thought about this application! An interesting improvement would be to add a control loop from cells temperature to a fan. This way you could improve the efficiency
I once built a similar setup,
my setup used 10 of those 12706 modules all wired in series. Then i used a cheap solar mppt ~30€ and charged a thrown away car battery with it.
I sandwiched the 10 peltiers between 2 aluminium sheets (4 and 5 millimeter). One being the hot side 5mm directly on a stove - the second one being the cold side cooled by water 4mm.
Now the cold side being a plain aluminum plate surely isnt ideal but it keeps it cold to the touch.
I clamped every peltier between the two plates with 2 screws each. I used thermal compound for maximum heat transfer on both sides.
I was able to generate 3W for a short amount of time. Now i can only get a maximum of 1W
My design probably failed at thermal expansion. When i first heated it up you could hear it click as it expanded.
So you would ideally need:
A mppt controller (i dont know if cheap solar works tough)
The highest transfer of heat you can manage through the modules. I believe they work up to ~130°C applied on the hot side. The cold side should stay as cold as possible with as little effort as possible.
There is no maximum thermal difference (except maybe because of thermal expansion) and as the TECs are intended for cooling this may be more relevant to cooling performance
You also need to properly clamp the modules between the plates. There are application guides on the web with pressure values for peltiers which should have been tested. It apparently effects the results by a lot.
Meister Jambo made a video on his solution to this problem. Maybe a solution you could try as it seems the least expensive and he also generated high amounts of power with lesser modules.
I am looking forward to part 2 and maybe i will revise my design then.
I was thinking of 3 ways to continue the cooling process for the top heatsink:
1. To have a small DC fan on top of the heatsink blowing downwards,that draws power from the Peltier devices.
2. To have the setup on the side of the water bath so that the Peltier fan can be close to it and still touch the surface of the stove.
3. To have an insulated pipe running down vertically from outside that may provide passive cool air flow, placed pointing on top of the top heatsink.
Just some ideas that may still need more testing.
One idea like what you made, is to make a standardized section of stove pipe with the peltier generation which could be added to any sort of furnace that uses the standard pipe. A specific application I had in mind is for wood fired, outdoor furnaces. They have a heat exchanger to make hot water which is pumped to radiators in the house. The downside is that there has to be a water pump to move the heated water. I thought it would be great if you could power the pump with thermoelectric generation, so even if the power was out, you could still heat your house. If the stove pipe is outside in the cold, there will be a bigger temperature differential to help make more power.
Love your pipe setup.
I would extent the cold-side heat sink all the way down to the floor.
To support the weight of the pipe and your generator, and to grab updrafts from the cold floor, to cool the heat sink by natural convection.
No cooling fans will be needed.
Use those heat differential fans to cool the cold side - use them to draw in cool air over the heatsinks for the TECs and then through the fans
Ive been using peltiers on my wood burner to power led lighting and fans. Also PTC elements direct from solar, inside sand batteries for storage heaters. Always works well in combination.
lighting alone is a total WIN, before the LED revolution i never realized how important it was because the tech we had sucked so bad...in the early 80s we had a cool device from Coleman that ran on fuel to power a fiberglass filamented lamp, it was insanely bright and made a buzzing sound while it ran...
You might be able to pull in cold air from the outside and cool the cold side. The stove should create a negative pressure in the room. Thanks for a fun experiment!
SO many questions. So many ideas. I've been thinking about this exact experiment for years. Since so much heat is wasted through the vent, we can assume that all of that heat is harvestable. So, it doesn't make sense to just carry it away in one pipe. Why not a manifold that would separate the hot air into several pipes, or more simply, imagine a "pipe" that is 3 feet by 3 feet by 1" thick. It's basically a big 1" thick hollow box, with an adapter at the top and bottom to exhaust out the 6" pipe fitting or whatever it is. Now cut a square hole in the box. Leaving a 1" lip all around the front surface. Now you create a massive 3' by 3' door that can be screwed on and is sealed with exhaust gas silicon rubber. This "door" or panel cover is the platform, for the peltiers and heat sinks on the front. On the back of the door , you have fins going vertically, to guide the air from the bottom to the top for even distribution. Should cleaning ever be needed because of inefficient combustion, this "door" can be unscrewed and removed. Now all that would be enough if you wanted to stop there, because we could use convection to keep the hot side hot and the cold side cold, but lets say we went crazy, and created a second unit. The exact same size and shape. But, instead of putting it on the front, we flip the whole thing around, and now all the heat sinks are joined into one massive heat sink block, pressed against the wall, taking advantage of the thermal mass of the wall, for cooling, and instead of the bottom opening of the sink block taking in hot exhaust air, it takes in cool air from the ground, and even the ambient heat from the stove itself isn't rising directly into your heat sinks convection flow. Since you're in here already, take some of that energy for a single fan to force the cool ground air into the cooling block, just as a test to see if it increases efficiency or if it uses more power than it adds t the system. . At the top of the cooling block exhaust the now warmer air into the room. Of course with this method you could go insane attaching more and more peltiers to the ever cooling "cold" side air all over the room if you want. Since this heat exchanger doesn't carry any of the combustible gasses with it but let's not go there unless you want to make a really weird fun video. :)
This is fantastic. A few other engineers have tinkered with these devices to mixed results, overheating is an issue on the hot side across all experiments I have seen. possible solution might be to have one of those fans kick on at a critical time to bring the hot side back down. Perhaps a greater thermal mass to leach the heat/power from. Water is a great heat sink, adding an upside down bottle will allow it to self refill as it evaporates. Copper thermal tubes are a great, non mechanical, cooling devices that could be used in the system. OR not sealing the chimney square tube but allowing some air to travel through it will let it convect some air the hotter it gets, a manual baffle would allow you to dial it in. Just thoughts, the balance is between generating the right amount of heat on a wood stove and that is a tricky thing as the heating cooling cycle is very radical. Stability and repeatability will allow you to add longevity to the delicate electronics. Wood gas is an exciting idea but the reactor needed to do it would require a complete rework of that stove and would be more easily accomplish by finding compressor tanks or such in the scrap yard and starting from scratch, but also I think it is a worth while endeavor as the wood you collect is cheap, shelf stable fuel source, and a cabin in the woods will have access to this fuel.
Look into 'little aussie rockets' and kick around the idea of a rocket stove build if the shop stove needs a redesign.
Thank you for uploading this video. It made my day just seeing the thumb nail. Now I have to go, there are some wood crates to collect from the dumpsters at work, might come in handy for something.
Nice ... You got a classic old weller iron ... I got the exact same one, had it since the 80's ... good reliable irons ... Great video ...
I used power and peltiers and water cooling to cool drinks quickly, so it's almost the same ;)
Great video, what an amazing though to capture all of the wasted energy everywhere.
Food for thought, sir. It is the very edge of efficiency and I hope you get the power back or saved from what was used to build the devices. You have better 'hands on' experience. All the best Gerolf. Cheers!
The TEG is a wonderful piece of history, and it works.
All you need to do for the boiling water one is to set up a thermal siphon. Advantages are no moving parts, and it can help spread the heat from the wood stove.
Laptop computers typically use heat pipes to conduct the heat away. You might try a few of them on the cool side of your device. Thanks for another great video!
Like the concept of a ‘smart flue’ but rather than lighting just some basic digital info like temperature, burn duration etc? Perhaps a usb out for another fan? Great idea!
Submerging the hot side in boiling water to stop overheating is brilliant, but keep in mind that thin pieces of metal like fins can also act as thermal brakes. Also if you put a water heat exchanger on the hot side, you do not need a pump. If you place the hot outlet above the cold inlet heat convection will act as a natural pump pulling in cool water as hot water rises.
Very interesting. You can also use water heat exchangers to divert some of that heat back into some radiators.
I was thinking about limiting the heat on input side. My solutions were more complicated and less reliable. Nice work
In UK, similar stovetop fans comes with a bimetalic strip on the bottom than can rise it a little and prevent it form getting damaged. Big Clive have a video about it.
Interesting to see this, a company I'm working for is experimenting using peltier units to harvest energy from the condenser on a cryogenic system. Same issues but the differential is derived from cold (-170ºC).
2:27 one of the core concepts of improving tech is to figure out the principles behind it.
For electric, it’s like making a contained liquid system move externally. Coils are used to pickup as much energy influence as possible.
There’s other ways to influence electrons to start flowing. Different metals for example have thermal properties, others have different effects on temperature.
I love this idea! Adding active stuff is to be avoided - I totally love the idea of a passive power generator / light / fan from a wood fire! With a few more watts I could power a phone from a campfire!
Great Project! Have thought about similar stuff a coupe of years ago.
Getting the heat out of the system is a pain in the ***, but transporting heat is quite easy. so I would work with steam, like a couple of others have suggested. Pipe the steam outside to a condenser where you mount the peltier elements. It also has the advantage of getting the elements away from the stove. Get yourself a big cooking pot (maybe a pressure cooker, so you can experiment), mount a hose stem, connect an isolated pipe with a steam hose and than the condenser.
For the condenser I would go with a perforated pipe inside of a square tube. Mount the elements on the outside and you have enough room to run wires for each element along the edges which should improve troubleshooting. use metal sheets for heat dissipation, cut it in an angle to create fins that point upward for a more uniform dissipation, than bent the fins in different U shapes. For a prototype I wouldn't bother with a return pipe.
Also: I wouldn't use the exhaust pipe, there could be a danger of creosol condensation and a chimney fire.
Grüße ausm Pott
Nice. You could have a watchdog-driven fan to push cool air through the lower fins to protect the peltier devices.
To get a source of cooling: Make an outside combustion air feed to the stove thru a 3" or so pipe, as the stove draws in outside COLD winter air, direct it thru the heat sink on the cool side. This will supercool the devices and possibly prevent hot side damage. It would also up your heating capacity by reducing the infiltration of cooling air to the living space. Michael in Colorado.
Outstanding idea! I often wonder if you could generate power using weights just like in a clock movement. Because gravity is something that will never go away and everyone has it.