"Lots! Lots, and that's metric lots as well as imperial lots!" is going straight to my vocabulary

What about a watercooled aircompressor. Then you get compressed air for the workshop, and heating of the water.

+1 for heat pump. You might even be able to connect the compressor directly on the 2nd shaft. Get everything you need from an old fridge: don't forget the safety valves. And good luck for your cold. :)

5:35 "The plates seemed to have gained weight " 😅 those are some magical plates you got there!😂

Hey Tim, may have been said but the favorite for energy storage is a sand battery. How about stirring the sand to heat it, like a huge rock tumbler, low speed high torque can be used by large diameter tumbler and small diameter for high speed low torque. The paddle could be made variable diameter or pick up more if available energy rises. Cheers

If your metal plates gain weight from the friction, you can exchange them with somebody else whose plates lose weight from friction. Keep trading them back and forth and you'll solve each other's problems!

If you're worried about mechanical losses in the gearing, one way to mitigate that is to put the gears themselves in the fluid. Then the "waste" friction of the gears isn't waste at all!

Thinking of friction - what about car or even truck (lorry) brakes? They´re made to turn kinetic energy into heat and release it into the air (or in your case water) around. You could stack brake discs and pads inside a pot and control the friction with a spring pressing on the whole stack. The more rpm the windmill turns, the more pressure on the spring so alongside to the heat you get kind of a governor for the rpm of the mill. My idea is four brake pads, then the disc and then again four pads. Then the same setup again and again. The discs are turned by the shaft while the pads are held by some kind of track so they can move a little up and down (as necessary depending on the wear and tear) but not sideways. I´ve got lots of ideas for this, but no possibility to test it myself.

great idea Tim. a Cambridge science friend told me to heat water with our large water wheel, in our mill. i went down the gears and electricity generator route and only managed to turn 4kw of water power into 50v at 1 amp of electricity...we should have heated water. i was going to stir water in an old lagged hot water cylinder snd pre heat the hot water in the house.....fascinated to see what is the simplistic method of friction heat. following your ideas with great interest

Your reasoning for using plates makes sense. While I still think it would be feasible to get the magnets up to speed, I agree that it would be quite expensive. The death of many ideas, lol I wonder if higher-viscosity fluid inside of the paint can would be able to convert more of the torque into heat.

Heat pumps are a miracle, technology connections has explained it again and again a bajillion times better than I ever could!

I love when you have a big project going. And I love when you nicely prove how smart you are! You are a gentleman!

Thanks Tim. I'm enjoying this latest rabbit hole

As an electronics engineer, I would obviously default to a generator, but I really respect the mechanical approach. I honestly would have never of thought of it as an option. But I like it, alot. and the vibe im getting is your doing this for the fun of the project, not profit or anything like that. I think your on a pretty good path, you could do alot with 1kw of constant heat. Hope your feeling better soon Mate

Some old automotive AC systems used compressors that were powered directly by the engine belt via a pulley, I think such a thing could be a good candidate for running a heat pump if you can get your hands on one, I've also heard (though correct me if I'm wrong) that some hobbyists have built heat pumps / refrigeration systems using propane as a refrigerant.

The science of thermal dynamics is almost magical. It's way beyond me. Good luck and I am really excited about what you cook up. Thanks for bringing us along!

When will the narrow-gauge railway continue?

For the issue of needing an additional fan or pump along side the compressor to go with your heat pump option: You are building this to fit to a windmill that you want to use to concentrate heat... You can use the same 'fan' you're running your windmill with on your cold side, and your hot side fan can be whatever you were going to use to move the hot water from your friction generator. The sides of your windmill become your heat-capture 'radiators', warming your chilled fluid by allowing the same wind driving your windmill to blow over them and transfer energy into the system so you have more heat energy to pump out to your hot side. It may be more cost effective to build it as a relatively small refrigerant loop heat exchanger inside a larger brine tank/loop. The thermal safety wiring on things isn't really any more complex than you would need for your friction based machine - You do probably want something on there to monitor that your friction core isn't running dry and turning into a glowing lump waiting to fling itself apart after all... Remember: Every machine can become a smoke machine if you run it badly enough.

If you want to convert your windenergy into heat the maximum efficiency you can achieve (without a heatpump) is 100%. So 1 Joule of Kinetic Energy into 1 Joule of heat. If you use friction you will almost immeadiatly arrive at this efficiency. The problem is you can only heat up the water near the wind turbine and thus you need to transport the hot water in pipes. This lead to transport losses. Depending on the insulation and the outdoor temperature I would not underestimate these. Heat transfer is proportional to the temperature difference. For example: 40C Water and 20C ambient-> 20C temperature difference 40C Water and 0C ambient -> 40C temperature difference and thus double the heat loss. You need the heat in the winter and thus you would have to insulate the pipes very well in order to keep the losses reasonable (or even bury them) - wich is expensive. The efficiency of typical electrical generators is about 80%, the rest is lost to heat. So if you would chase the highest efficiency you could liquid cool your generator (also use the cooling water for heating) and use resistive heating (like standard waterboilers or kettles). Then you would achieve the same efficiency as the friction solution. If you do not cool your generator and use resistive heating you still end up with a efficiency of 80% - because resistive heating is 100% efficient. But electricity is a lot easier to transport than heat. Just lay some cables and you can transport it with significantly lower losses than heat - without pumps and worrying about insulation or leaks or ….. Transporting electricity also gets more efficient the colder your cables are. And the cost of the generator (alternator of old car) + cables + resistive heaters would probably be the same or even less than the friction heater + heat exchanger + pipes + insulation. While being a lot more „comfortable“ To sum it up: due to transport losses when transporting hot water and cost of pipes and insulation I would assume that converting your energy to electricity and using resistive heating is the best option in terms of efficiency and cost.

Know how you feel, had Man Flu three weeks ago and I'm still getting over it. 😂🤣 Hope your feeling better soon. 👍

Hi Tim, just an idea to get some more RPM if you look at my waterwheel build I used a shaft mounted 20-1 gearbox. they are called shaft mounted conveyor gearboxes. I have found that the one I used only get slightly warm when running at 16rpm with 2kw going through it. So I have 16rpm getting geared to 320rpm. then a 2.4-1 pulley belt drive that takes it up to 768rpm to run a 8pole induction motor. The loss in this setup is very low. nothing gets more than just warm to the touch. if you did a 5-1 pulley from the gearbox you could achieve some high rpm. 20 rpm x 20 = 400 rpm. then a 5-1 pulley =2000 rpm. there is losses but for 2kw the loss is in the region of 200-300w Also because a lot of the loss is happening in the gearbox itself and you are trying to make heat. that heat could be recovered from the gearbox as well. it would add complexity but is possible. The belt drive though would be to complicated to recover the heat so that would be lost But the closed gearbox unit could have a heat exchanger on it. I do like the induction heater idea. Neodymium magnets are so expensive and corrode. because size won't be much of an issue for you ferrite magnets could be much cheaper for the same magnetism and they have the benefit of not corroding much at all. these are big and reasonably priced www.first4magnets.com/rectangular-c35/152-4-x-101-4-x-25-4mm-thick-y30bh-ferrite-magnet-20kg-pull-p2549#ps_0_2570|ps_1_726 if you want any info on the gearboxes just send me and email mate. Great video.

Get well soon!

One up side to this project; converting energy to heat is literally the only thing you can do with 100% efficiency. If you want to keep things slow, consider a piston pump. Just a close fitting, but still leaky, piston pushed back and forth in a long tube should work. All the work needed to push the water thought the small space around the piston would go to heating the water. It would also have the advantage that it would be trivial to make it circulate water into a larger tank (or tanks). A little fun with an automotive type thermostat and you might even get regulated water temperature.

Completely get why you want to use the plates like this (some wheeled diggers basically use this for brakes - it works well! but it might be worth alternating materials so you don't get cold Welding / galling (not sure what's an easy/ cheap second layer, wood might be too low friction when wet and concrete might wear the steel to quick? - oil could be used instead of water too for higher friction materials ). Another cheapish option for magnetic heating is just submerging an old pm motor in oil, and shorting its windings (through a few metres of thick wire which is also under oil). The windings are normal good to at least 180c (a longer shorting wire can increase its resistance and lower running temp if to hot - or a big resistor bank could be used ). Ac works better for this as brushes wear and knacker bearings if in oil, the brushes might not cope with the current too - but dc would still work for a while though!

Hi Tim, thanks for the entertaining video - loved the bit where the plates gained weight - always knew Ireland was a place where magic happened! Get well soon; looking forward to the next stage of this adventure.

Awesome series I can't wait to see the finished windmill friction based water heater

Tim, I would suggest looking at a company called Kora in Germany, who specialise in making small mechanically driven heat pumps for wind power.

Loving this and hopefully a nice distraction from man flu! I'm with you Tim, keep it simple, slow and within the whole windMILL ethos.

I hope you feel better soon Tim. Thanks for the video. Interesting. It will be good to have an independent view on heat pumps. I'll look forward to your investigations

Tim, if you do end up building a windmill, make sure to make it huuuge. This way, it's going to be amazing no matter what.

My door bike trainer uses rotating magnets rotating in an aluminium housing to convert rotation into heat. No rubbing or wear, and you can control how close the magnets are to the aluminium to control the torque…maybe second hand “turbo trainers” could be a useful source of parts.

Hi Tim. I'm glad you mentioned Induction Heating. It is probably the simplest of the "no contact" methods, and the need for high speed can be avoided by using a larger diameter. Even a large annular ring would do. (although there are many designs on the web for directly driven wind generators which have a relatively small diameter). But when you think about Induction heating, then it's only a simple step to generating electricity directly. Having your energy in electrical form has so many advantages. The obvious method is to use a surplus AC motor connected as a generator. You can pick up large motors for scrap metal prices. Further, if you don't need a precise frequency, you could do away with speed regulation. You'll find many designs on the web for people using AC motors as wind or hydro generators. Likewise there are many designs for home-made Generators using magnets embedded in wooden disks. I think you should definitely be thinking about homemade AC or DC generators to convert wind energy to heat. P.S. I still think that Solar electric heating is the way to go. I heat my small shack with a fairly large solar array, set of Lithium batteries and a heat-pump Air-con. Last night was down to about 3 degrees and my air-con was drawing about 300 watts continuous. And this morning the batteries were back up to 100% by midday. However the secret is very efficient insulation (double glazing and heat-exchange ventilation), while the payoff is perfect thermal regulation with zero maintenance.

I did miss your comment about a heat exchanger in your previous video hence why I suggested a generator powered by the windmill and a heat pump, but I look forward to seeing you work on this idea and any others.

Heat pump is a great idea. Also the commenter was right about the efficiency. It's calculated by energy used vs energy moved so it can be above 100%. The steel friction plate idea just creates too much particles and wear. Have you looked into the torque converters? Converters can generate tons of heat with mostly torque not rpm. The stall is greatly variable. Like your videos I will keep watching.

Tim doesn't think outside the box, he asks what box? Spent semester in college studying solar water heating, it is forgotten, with everyone one the solar power band wagon, it can be a fairly simple way to do such things as heat your house,

well, I learn from you, and I listen, so keep them comming. cheers from Denmark

This nerding out when you're sick is definitely a symptom of the early onset of chronic boffinism.

what you also can do is using very viscous oil. that'll slow down the abrasion of the metal plates and increase friction by quite a lot. it should even be possible to not have the metal plates touch each other and still create a lot of heat when the oil is viscous enough.

Do you remember your steam machine cylinder? If you pump water through a small hole the energy you need for pressing is converted into heat. You only need a crankshaft (ball bearing) and the rod is pumping water in circle on the bootom of your mill. Use some screw (needle valve) to find the optimal hole diameter.....

I made an induction heating device, a few decades ago, that easily boiled water, when operating at 400 RPM. It had 16 magnets, arranged on the face of a 400mm steel disc. These faced an aluminium plate, with a clearance of about 4mm. When spun at a mere 400 rpm, the plate soon reached 200 degrees C, and turned water into steam :) . That's the way to do it, in my humble opinion.

What about a highly viscus oil or paste? Machine the plates to have tiny oil channels in them extending out radially and use the thickest oil you can find and maybe mix in a grease to thicken further. The oil channels will ensure there is a small gap between the plates once they wear in but then wear should dramatically drop off afterwards. Want more friction? Put a little pressure on the plate sandwich like a clutch. Want to run at lower RPM? Make the thing WIDER. Added benefits: it won't evaporate, it won't rust, great thermal properties, it could go above water's boiling temperature without pressurizing, the right oil can self-regulate to lower it's viscosity (friction) as temperature rises.

Thanks for posting

If you're going to have heat exchangers between the liquid around the friction plates, and the water in the storage tank, you could put other materials around the friction plates to generate the heat. Maybe instead of water, fill the friction plate container with oil, sand, or salt. Solids like sand or salt could generate more friction and more heat at a lower RPM.

You do not need rotational speed, you actually need linear speed to make the hydrodynamic friction work. So, instead of increasing the RPM, you can increase the diameter of the rotating element, thus reducing the losses from gearing.

I will vote for two different type systems: 1) a shaft driven air conditioning compressor connected to provide heating or cooling as needed. The air conditioning compressor shaft would be mechanically driven by your windmill with the reduction gearboxes mentioned by Kris in another comment here. The crankshaft rotation speed would not be very high so you would need a large volume compressor. It might be necessary to be able to connect more than one shaft driven compressor to the large driving gear or chain so that under higher wind conditions more heat can be generated and stored. Instead of commercial refrigeration gases you could use a mixture of mostly propane with some butane, study AZEOTROPE. The whole contraption would be located inside the rotating head of your windmill the heat that is generated would be transferred with a heat exchanger liquid, think about the hydraulic connections in an excavator. Yes, propane is flammable and explosive so precautions have to be taken. I built a home-made air conditioner using car antifreeze as the heat transfer liquid for our boss under his detailed instructions when a summer student in a maintenance shop in the 1960s. 2) build a very large circumference alternator that can produce significant amounts of electricity at slow rotational speeds using only copper coils and iron cores from used transformers, no need for large numbers of magnets.

Very cool! (sorry for the pun) Praying you feel better soon.

Cheers Tim, I'll look at the article. 👍💪✌

Very interesting subject!! Following with interest. Really hope you come with a good solution. In the summertime you could let water through tiny but long tubes placed on the roof or similar. When sunny the temp could get very high.

Good idea about reducing the number of energy conversions so using friction is a good wheeze imho. To increase it even more you make the rubbing surfaces rougher by pitting or some welding blobs or some such which will also wear but create more friction while it is rough. Also, if you add some weight to force the plates together, more friction too - the resisting force is mu, the friction coefficient, times the applied load - so if you squeeze the plates together, it will be harder to turn and generate more heat, but you must balance against the rotating speed - the work you get out is force times velocity, so a bit of experimenting to find a good balance. Good luck and get well soon

Hey Tim! I know you want to invent and build, but if you manage to build the wind mill, you could get a heatpump style water heater (they are available in the USA) and drive the compressor with the mill instead of a motor. Then you would have a proper hot water tank from which you can use the hot water for whatever purpose you like.

Hope you feel better soon!

Tim, just a thought but why reinvent the wheel spinning discs that generate heat with a friction material have been used on cars for decades it's disc brakes you could stack brake discs on a shaft and the callipers could give you a varying degree of friction spun up in water etc to transfer the heat, even the pads are "consumables" for ease of service. as a mechanic I usually think car parts, whatever you build will be amazing and cant wait to see it.

Love the video, Tim Tim

Here's another crazy idea: what if you used one of the high-speed options, but put the step-up gearbox in the same water vat you're trying to warm up? That way any heat generated by those gears isn't actually lost. Since gear boxes are often sealed and lubricated units, I wonder if it could operate under water.

About heat pumps. If you're only interested in the Heat itself generated by compressing gas. You can do it with a cheap air pump. No expensive gases needed. Imagine an insulated bicycle pump connected a one way valve (tire valve) to a water cooled turbo inter cooler (insulated) and a needle valve to the outside. The pump will create pressure and heat that will transferred to the water in the inter cooler and the needle valve will make sure the system will stay unter pressure to make the heat exchange effective. If my rough calculation is right, you will only get 125% to 150% efficiency this way. But that's just a bonus for you. You only need 5-8 bar to create quite a lot of heat. I remember melting (softening to the point of deforming) a cheap plastic bicycle pump in the heat of summer while pumping up a big tire.

suggestion: carve impeller like channels into the plates and use oil instead, should signifficantly reduce wear while also circulating the fluid for better heat transfer. don't know if it would be better or worse at heating though, on one hand the oil is experiancing friction on the other it might be less than steel on steel

I find all of this information very interesting and hope it continues. I have one thing to add that has nothing to do with generating the heat. My suggestion would be whatever you want to warm up such as a home or workshop the first thing that you do is super insulated. I'm not talking about insulating beyond stupidity, I'm talking about taking advantage of every opportunity you can to keep the heat that you make within the structure. Many people do not realize that even burning wood for a heat source uses air inside your structure which you have already heated and you're using it for combustion and it's going up the chimney. In the case of using wood as a heat source, an outside combustion air source would be a good idea for your woodstove, pellet stove etc.. Keep up the good work.

I totally love all the practical simplicity of all your projects. Ofc. there is more advanced tech on everything. And ofc. you can buy all tech and build it. But going back to some roots of engineering, taking the scrap that dont cost much or anything at all, invest time and thinking. Then come up with a project that is amazing to watch. Bake this toghether with some really charm talking and real knowledge. as I said I love it. Your videos inspire, Alot of the videos you made inspired me and gave me ideas. I am also sure that you really enjoy your projects and use your brain to make it as simple as possible to fit the needs you have. Thank you for your channel. It is very entertaining and soothing. I really hope this project continue in a form that suits your needs! Regards!

thank you for this follow-up video. the induction heaters may require high speeds, but there is less friction and torque required to drive them. I'm sure you already are aware of this, just wanted to comment this anyway lol. I'm still rooting for the generator though

Hi Tim- thinking about your heat exchanger design- what if … the last turning plate in the stack was slightly larger that the rest and on the outside, had some fins to create a centrifugal pump? You could then shape the container (the paint bucket) to have an incoming and outgoing port, to the circulate the heated water (or oil) around a heat exchanger coil inside the insulated tank? This would probably make the heat transfer more efficient. You might even be able to do away with the heat transfer tank altogether if the pumping action is good enough to run a hydronic heating system directly for example…

I can think of only one heat pump setup that'll meet your requirements. Traditional heat pumps use hermetically sealed compressors require making electricity, however, you could probably pull the entire air conditioner out of a junked car. They are belt driven at not particularly high speeds (using a mechanical seal rather than being hermetically sealed) and would probably do the job. You can just dunk the hot side radiator in a cooler and pump water through that cooler.

Another +1 for a heatpump. You can get the parts for cheap/free from an old fridge, freezer or air conditioner (although not that many of thoes in Ireland) and can get what looks like more than 100% efficiency!

If you have a low RPM shaft, you can have a gear train bringing that up to high speed and then spinning some paddles and put the WHOLE LOT in a singke vat of oil. So you get the high RPM spinning paddles in oil, and all the losses from the gear train are just added heat into your oil (which is then heat-exchanged onwards) and wear will be very low. The water -cooled workshop air compressor idea in another comment is excellent, though, and basically asimple heat pump too :-)

Thanks Tim 😊

If you are already treating the steal plates as consumable, rust is a good thing. Iron rusting is an exothermic reaction, it adds some minimal heat to the system.

I'd suggest using oil instead of water for the inner tank as I think rust will be more of an issue than you think. If you put the gears under the fluid as well then the gears are nearly 100% efficient as they lose efficiency through heat. Do as much gearing as you want under the fluid and you are not limited to metal on metal friction. I prefer the heat pump idea. See if you can pick up an old cheap freezer or fridge pump. Lot's of interesting ways of getting the heat to pump (air source, ground source , solar water heater, compost/manure heaps)

if you are going to do plates, make sure to preload them against each other, so there is always a certain amount of pressure ensuring good contact. also, friction is proportional to normal force (in this case, clamping force btw plates)

For a source of cheap magnets - perhaps you can find a school or business with a lot of old IT gear. Spinning hardrives contain a couple of very strong magnets, and the drives themselves are practically worthless after a few years service - I have 10 knocking around right now that are just essentially waiting to be destroyed securely, and that's just one nerd's worth!

As you said in the film the term efficiency for a heat pump or refrigerator is misleading. Efficiency describes the output compared to the input. i.e. the proportion of the energy driving the heat pump that is responsible for “moving” the heat from the cold reservoir to the hot. You may have a 50W motor driving the compressor delivering 40W of work (80% efficiency) The coefficient of performance (COP)is the term that can be above 100. The 50W heat pump moving 100W of heat from cold to hot has a COP of 2 or 200%. Love the channel one of the best available.

In all the aquaponics, fishtanks ect I have always put some steel bolts in the tank's as when the colonised beneficial bacteria help break down the iron and over time the bacteria turned the souroundings into a iron sludge. The same happens inside car radiator's ect. You'll always have some kind of erosion. The magnets spinning past blocks of copper can get so hot it can melt aluminium and have zero affects on longevity ect.

I was down on the metal on metal at first, but I think if you filled the tank with a mineral oil (or maybe even just used motor oil?) that would make the system last longer, and maybe even generate more heat due to the higher viscosity of the oils instead of water. All you'd have to do is have a little magnet in there to collect all the rust and other bits, to keep them away from jamming the whole thing up

I just had an idea for you. Why not a belt drive on a fixed pipe filled with water. The rubber belt or even leather will give great friction. It's also used as a method of fire by friction if I recall. Edit it's called thong friction fire method. Also you can roll a ring the width of the turbine and use that as the belt drive for maximum speed ratio instead of the slower drive shaft. Cheers J

with your issue about the speed of the magnets, you could achieve those high speeds with flywheels it also could just be large flat discs use the 400 rpm you might have free from the final drive of the windmill itself, and onto a fly wheel and it might be a fast enough speed at the edges, the heating plate could also be hollow, less to heat as well

All you really need is a state change material or in other words something that you can cause to condense and then boil under controlled conditions. This is how most cooling systems work and is exactly how heat pumps work. If you get a pump and a valve/backpressure regulator along with two air tight containers piped together you can make a heat pump to gather heat from the air around one side of the unit and transfer it to the other side and into either air or liquid. You can technically do this with water if one of the vessels is under a vacuum but it would be easier to use a substance that is liquid at the desired temperature when under a specific amount of pressure. Something like propane is a great example, at ambient pressure it is a gas but if you compress it to 2-3 bar it will turn into a liquid again. The higher the pressure the hotter it can be when it is a liquid. Also of note is that you can do this with air as well in a closed loop with just two heat exchangers, one on the high pressure discharge and one on the low pressure suction with a backpressure regulator in between. Just compressing the air will increase its temperature both through friction from the compressor and because during compression you’re adding energy to the air. The first heat exchanger transfers the heat to your water and then you go through the valve to the low pressure side of the unit, which will drop the the temperature of the air by around 17 degrees c for every 1 bar of pressure drop, you then use the other heat exchanger to transfer ambient heat energy to the air and then it gets re compressed and continues the cycle. You can also do this with a non sealed system where the air is just released out of the valve after going through the first heat exchanger. The goal is to have the compressor never stop operating so you’re always flowing the air. If you add a liquid cooling jacket to the compressor you can also scavenge that heat while cooling the compressor in order to make the whole system that much more efficient. If you want more details or just want to pick my brain on anything let me know. I’m a controls engineer who works with industrial equipment and high horsepower compressors as well as a tinkerer who likes to solve problems from new angles because “that’s the way we’ve always done it” is my least favorite excuse to do something.

How about using the turbine to power the flywheel on the compressed air engine! And use that as your compressor. As for gearing maybe a belt or chain drive would be more efficient way to get a gear ratio and transport the power down the ground level

It is somewhat complicated to generate power, but that also has a lot of advantages, like more ways to optimize output to varying wind speeds. Also, power is always useful, even when the heat storage is at capacity. Using the power to pump heat pump can make the heat gain more than compensate for additional transmission losses. Gearing to increase speed can be done in few steps with large gear ratios. Although generating power, and then use a heat pump is "involved", I wouldn't be surprised if generating meaningful heat more than occasionally by friction, without having to manage the system very frequently turns out to be more difficult in practice. Motors that can be converted to generators and heat pump systems that could be use after some modification/repair and refill is discarded every day. That said, I'll be more impressed than surprised if you manage to make a reasonably practical system based on friction.

I'd think a Sterling-engine-type heat pump would be fairly elegant. They don't have a lot of moving parts, and the compressor is the pump for moving air from the hot side to the cold side and back. I'm no engineer, though, so I could be wrong.

A mix of pitch and light oil fractions would allow arbitrarily high viscosity, since pitch is just so dang viscous. Just mix it at even the 80RPM and it should have enough friction as long as you tune the mix correctly, plus it is a lubricant you can use to reduce friction on the vertical shaft if it ends in the container. As viscosity drops with temperature it may get awkward, as the warmer it gets the less of a load it puts on the mill, allowing it to spin faster, but you were already experimenting with some speed governors that probably can alleviate it, plus at higher temperatures it'd lose more energy, so logically speaking the viscosity can't drop forever. A bimetallic strip located in the container that operates a vent to let off excess heat could probably work well, maybe in series with a curved piece of springy metal that holds the flap closed until some boundary temperature when it can open. Or the bimetalic strip could somehow operate a gearbox that closes a larger flap than the strip could... though I have trouble thinking of a way to achieve that without having to make an actual gearbox. But then again, you would have a tub of lubricant to work with anyways so maybe it could be viable?

Get well soon, and do investigate the magnet idea at small scale before you drop it. I agree the heat pump idea is too fiddly for what you're looking to do.

Efficiency is usually thought of as "How much of the energy put into this thing actually did what we wanted it to do." The rest is lost as heat. And energy is never lost or destroyed, it can just go some place that isnt useful to us. So "efficiency" and "energy loss" dont always mean the same thing when it comes to heaters, very especially heaters that dont use a fuel. An electric heater is 100% efficient: all the energy it uses ends up as heat. A 1000 watt space heater, a 1000 watt high efficiency LED light, and a bitcoin mining computer using 1000 watts will all heat up a room identically. So, whatever you have the output shaft of that windmill doing, as long as its only barely able to do it, it will be making heat. Grinding steel plates against each other, stirring a fluid, moving magnetic fields past a conductor, whatever. Just add load until the windmill can just barely do it. Normally I'd say add a flywheel to help average out the input energy of the wind vs the load, but the mass of the sails/turbine and rest of the system are probably enough.

some type of adjustable spring to compress the plates would allow you to use all the torque when the wind changes. If it's a not so windy day then lessen the tension on the spring to keep things running then when the wind blows you can tension up the spring to get the most friction.

The whisk, impeller, or orifice designs might work well at low speed if you use a high-viscosity working fluid, such as a gear oil. A non-newtonian fluid such as cornstarch suspension might also be useful, and could even serve as a sort of speed governor for the wind turbine. I also like the heat pump idea, as if the coefficient of performance is 2-3, then the powertrain and electric generator (assuming electric drive) could be as little as 50%-33% efficient and still break even with direct friction heating.

5:30 iron oxide weights more than metallic iron. maybe the heat, friction, and water caused the plates to oxidize? no idea tho haha

The only loss of a generator would be the generator itself if you were heating with a resistive heating coil. Generators are usually around 87-92% efficiency, the resistive coil is 100% efficient at turning electricity to heat. Plus you also gain the benefit of being able to charge some batteries when water heating isn't needed.

Thanks for once more patiently explaining your thought processes. :) I love the idea of a heat pump but I wonder how well it would work at the varying RPMs that would be provided by something like a wind turbine. And either way it definitely drives up the complexity and cost over just steel plates rubbing away.

Car air conditioner is much simpler. With a small compressor that is belt driven. The hot side radiator could place in water to heat or a fan to blow heat. Of course the cold side radiator will give cooling for summer.

I think opting for more thinner metal pieces would be better. You have to consider that thick metal is mostly metal in your mechanism, and thin metal will be more water. The only thick one may be the top one to compress them. Another thing for compression maybe bolt the stator plates together. I would coat a rotor shaft in some kind of plastic or heat insulator material to not wick out the heat.

Grease. The function of this heater is to run all the time and ideally be low-maintenance. By using Grease you're providing lubrication and using grease shear to generate heat. The downside is it takes longer to get up to speed. The upside is set it and forget it until it makes unusual sounds😂

This is fascinating. I really want to know how an oil would change the outcome from the design you have.

Thanks

Man, i hope someone comes through with a couple hundred magnets for you. Im sure you would create an awesome Mad Max setup with them.

The compressor in a heat pump does move vapour, to be specific superheated vapour, that is that it heated above its saturation temperature and this can apply to gases that to the touch feel extremely hot and gases that are extremely cold can in fact be superheated. While the compressor may only be moving a refrigerant vapour it’s the physics of the vapour compression cycle and the condensing of the higher temperature and pressure vapour into a liquid and the subsequent expansion of the liquid back into a vapour where the process stops being just about SENSIBLE HEAT and becomes a process where LATENT HEAT where far more energy is absorbed by an evaporator and then rejected by a compressor. For example to change 1kg of water by 1°C (which is sensible heat) required 4.187kj/kg, to change that 1kg of water to saturated steam at the boiling point will require an additional 2260kj/kg just to change state and the same principle applies to freezing but it requires around 330kj/kg at the freezing point for the state change. Heat pumps take advantage of this process as they absorb from one medium and reject it into another PLUS when you are using the rejected heat you get not only the absorbed heat but you also get the heat of compression and the electrical energy that has been added, that’s why heat pumps are so efficient. While they are very efficient they are much more complex than using the heat generated from rotating motion and very unlikely that anyone could engineer a system that directly drove a compressor with a variable energy source like wind.

To lower RPM for contactless system you can use different, more viscose liquid. As additional benefit it will self regulate, because if it start overheat it becomes less viscose which lower friction and stabilise energy transfer.

How about a wood gas generator? You could use your wood chipper for charcoal to generate the fuel. Stopping the gas generation at an appropriate time could yield both gas for heating and charcoal for sale.

Shock absorbers from vehicles will turn movement into heat, and might be easy enough to rebuild to be more constricted and work on low rpms. Also some buses use magnetic breaks where they have a metal disk but the break pads are electro magnets. If that works with your speed fypu could later switch to a big neodymium magnet. Less investment during prototyping.

The main problem I can foresee with the friction heater is in the exchange. It certainly would work to heat up water, as your clever testing shows, but how efficiently can that heat be exchanged into the water you actually want warmed up? That's an open question, and I think perhaps you might need to run a second experiment with a primary container that is sealed up a bit better than your first paint can test, and place that into a second container to see how well it heats (of course the best exchanger will be one designed to maximize surface area, but this basic set up would work for a test). Other methods like electric might lose some efficiency in the conversion, but would that end up being more efficient over all because it could heat the water directly? Again, that's an open question. I am intrigued by the idea of a wind powered heat pump. The main question there is whether or not you can get a high enough pressure. If you were curious to try it, old school heat pumps used ammonia for their exchange gas; still a potential for danger when under pressure and breathing, but certainly safer and cheaper to obtain for testing purposes than other refrigerants. Since you mentioned induction heaters, would there be any reason you couldn't do that in combination with the friction heaters if you're using steel plates? Perhaps using electro magnets rather than rare earth magnets? If you do end up trying a design like that, consider if you can make a double shaft and have the plates rotating one direction while the magnets rotate the other, you're effectively doubling your speed without having to make the contraption actually spin any faster.

the biggest advantage of friction, or solely converting your wind power to heat, is that brakes can be applied HARDER as required. the power in the wind increases on the cube of the velocity. twice the windspeed is FOUR TIMES THE POWER. with a pump, compressor, generator... there is a certain windspeed required to produce sufficient torque to drive the device... and thats it. any higher, you have to apply BRAKES, and any slower, it simply doesnt work at all. take a water pump, it lifts 1 litre of water 1 metre on every stroke, say. it takes so many watts to do that. it doesnt matter how fast it runs, its always lifting 1 litre 1 metre, its always placing the same load on the wind turbine. the only options are to reduce the TURBINE efficiency, feather blades, point out of wind, apply brakes, whereas if one works towards simply converting wind power to heat, it can extract ALL the power... ALL the time. the sensible approach to storing wind power would be as thermal energy. you can extract all teh power, all the time, and always have somewhere to DUMP it. you cant fill a bucket fuller than what it can hold... a steam turbine doesnt care if you use solar, wind, coal, gas, or nukes... it just wants hot water and steam!

I had a look at the design of plate heat exchangers and it looks like plates are separated by gaskets. The plates have holes in them like a radiator grill,

what if you adapt brakes from a scrap car? they're specifically designed to apply a variable, controlled amount of torque to slow down a wheel and generate heat.

I hope there isn't going to be a test? Because I don't have time to study, really. But I am always ALL attention. Goodness - the things I'm learning