Turning kinetic energy from wind directly into heat (hot water)

From what I understand, the primary problem with this idea, is that the incredible multiple shock forces distributed from the cavitating gasses, will stress out your propeller materials, where the heat is generated.  I'm not sure if I missed this being addressed above, as I did not read the entirety of the thread (skimmed it though... pretty interesting).  

I can see how that could be a problem if a person was considering standard "propellers". The problem is, there is no word to describe a heat generating cavitation pump. It really is not a pump because you are not really moving water...you are heating it as another pump passes it through. And it is not really a "propeller" either as that requires thinness to get the proper curvature to move air or water. I guess you call it a billet with holes because it is this mass thingy, acting as a flywheel with holes bored in it to producing imploding bubbles. What in blue blazes do you call that? I call it a propeller, but it is not a great term I know.

The workaround that would be the same workaround we used to build rudders at the shipyard that endured intense cavitation; hardened steel.

You just have to love the Government of India, but they have no secrets...if it can benefit their constituents, they put it on the internet in the hopes that others can benefit from it.

It seems Cavitation heaters are all secretive, but they spelled it out pretty clearly. They never said the bore or diameter of the drum, but I would guess the size to be about 18 inches long and 12 inches in diameter. What really seems to be the secret is the holes bored in the drum, but this they said with clarity. Holes 10 mm in diameter drilled 15 mm deep and at a 45 degree angle. That provides the best cavitation in a given bore. It also showed that they brought circulating water from 68 degrees up to 140 degrees in 1200 seconds (20 minutes) at 1750 rpm with a 1/2 horse power motor. That is quite a bit of time granted to heat 5 gallons of water, but was still 87% efficient. That is darn good.

So then I started to see what a vertical axis windmill spun at, and it is around 37 rpm depending upon its size. At that speed you would need a gear ratio of 1 to 350 to spin the cavitation pump to 1750 rpm; the same as the electric motor. Even with planetary gearing, I see that as a challenge in a do it yourself setting. I could of course build the pump bigger, make the pump more efficient, or just hope that the long term duration of wind storms here are enough to justify the cost of building the thing.

My wife and I did discuss the option of building a electric motor powered cavitation pump and heating my home that way, it is pretty much built for it, but I am not keen on using electricity to heat my home. I think wind has potential.

I am thinking what I should do is build a scale model of my windmill, gear box, cavitation pump and water circulating system and see how it all lays out.

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Travis,

Have you considered the wind aspect as perhaps just a supplement?  What I am thinking is that if you had VAWT direct-drive coupled to your rotor/cavitation drums that were submerged in water that is a few feet below ground, like a septic tank, you would not have to worry about freezing water.  The ground would keep the water around the same temperature as well-water when the wind is not blowing, but when wind was available, there would be a gradation of 'water heating' from minute to maximum, all depending on the wind speed.  If this water were being direct fed into some in-home water heating unit(s) (wood-fired, tank water heater, point of use water heaters, etc.,) then *they* would not have to raise the temp of that incoming water so high.  And if the incoming water was already quite warm to hot, then depending on how the thermostats on the water heaters were set they might not have to fire at all.  If this system were ported, in-line, with solar water heating in the summer, that would just be more bang for your solar buck.

My heating system is a little different than most, in that it does not take high heat to operate, but rather low heat. As long as the main loop on my boiler system stays above 100 degrees...no matter what is providing that heat to the main boiler loop; solar, wood, coal, or even wind cavitation; my propane boiler will not come on. But should that temperature drop below 100 degrees, the propane boiler would come on. In some ways that is good, and in some ays that is bad.

The good part of it is, when the wind was not blowing, the propane boiler would send hot water circulating through the wind powered cavitation heater. That is kind of good because there could never be a freeze up, nor would the cavitation heater have to truly work to heat water from ground temperature of 57 degrees to 195 degrees. The lowest it would be is 100 degrees, the start up point of the boiler. In this way the whole system would be automated...when the wind was blowing the cavitation heater would save on propane consumption, but the second the winds died down, the propane boiler would just do what it always did and cycle on and off as needed.

The bad part is, the main boiler loop that constantly stays between 100-150 degrees, would now be 60 feet long instead of 5 feet. It could be super insulated to save heat loss, but I would inevitably lose some heat. I think the wind cavitation pump would greatly make up any extra propane the boiler burned making this extra heat, but it does eat into the efficiency some. You could automate the system with some zone valves too though. It would not be that hard, but adds some complexity to the system.

Your point about a hybrid system does go straight to the point though, and it is a tough one. I happen to have a boiler sitting right in my garage, not hooked up but ready to be. It would take about the same amount of money and time to build a windmill cavitation pump as it would to hook up that wood/coal boiler. If the wind caviation heater worked, it would save me the trouble of buying coal or putting up firewood, yet without question the wood/coal boiler would provide all the heat I need for my home. I cannot say that about the wind cavitation heater as I would need my propane boiler to come on when the wind was not blowing. You could install both, but then you have double the installation costs.

I am actually leaning more towards the wind powered cavitation pump only because I am not a huge fan of firewood.

Just adding the following link as noted before, but with the accessory mentioned at that site that may be relevant here:  http://www.yukon-eagle.com/FURNACES/THEHOTRODWATERHEATER/tabid/61/Default.aspx

You are likely surrounded by wood, Travis, and it will be your closest go-to source of heat when the sun isn't shining and the wind isn't blowing (outside of the geothermal under your feet).  Sure, as we age, the prospect of putting up wood looks daunting.  But maybe worry about that more when you get there....the cost of a fossil fuel at that point may make the cost of hiring out your woodcutting to be an acceptable expenditure.

Yeah I have the ability to install one of those on my boiler; I have a New Yorker WC-90 boiler so they have a port where a copper coil can be added.

The problem with wood is not if I have enough, it is that I cut too much of the stuff. I average about 10 cord of wood a week, though granted not a lot of it is firewood; most is pulpwood and sawlogs. Typically I cut a couple of loads of wood and sell it and just buy my propane, but I would not mind a better way.

Part of that is just being able to use the abundant wind here, and the other aspect of it is I am just plain petrified of a woodstove. Honestly, even though I have all the equipment and wood to burn, I most likely would burn coal just for the safety factor (that is what the W/C stands for...wood/coal). There is the longer burn times and ease of use of coal for sure, but it primarily is because you just cannot have a chimney fire with coal since it has no creosote. I LIKE THAT!!

So you can kind of see, if I cut my propane consumption down, did not have to resort to wood or even coal, I would be a pretty happy farmer.

You mentioned in another thread that you came to Permies partly to research Rocket Stoves, but when you talk about considering burning coal instead of wood, you mention creosote, and chimney fires:

There is the longer burn times and ease of use of coal for sure, but it primarily is because you just cannot have a chimney fire with coal since it has no creosote. I LIKE THAT!!  

  With a properly built Rocket Stove, you can't have a real chimney fire either since you are having a controlled chimney fire, in the super heated burn chamber/tunnel and heat riser, which burns off what would be the cooler gasses and particulate (in a regular wood stove) that might produce creosote.  A batch box RMH takes care of the longer burn time aspect.

The problem with wood is not if I have enough, it is that I cut too much of the stuff.

The fuel savings of having the RMH would show in labor reductions, and you wouldn't have to sell wood to buy propane... or a lot less.  If you hooked up your RMH to produce hot water, heating water for your floor, then you are killing two birds with one stone... or actually the same bird (heating your house) with two stones.  ...or even three, since there's the barrel radiating, the slow radiant of the bench, and the hot water in the floor.    

It was interesting, a good friend of mine who is in a very similar situation as me, land wise, family wise, income wise and so on, just said, "I have been immersed in rocket stoves lately". I thought I knew what it was, double-checked and was thinking of something else. That drove me here anyway, and it was enlightening.

I have not seriously considered building one, though I really do not know why. I guess it was because I do have a perfectly capable wood boiler just sitting in my garage waiting to be hooked up. That does not mean however that I must be married to it, I could sell it and use the proceeds to do other heat generating ideas.

I am familiar enough to know the basic principals, and in my early years as a welder learned as most welders do by being on the wrong side of industrial boilers (the 6 story tall ones) and I learned quickly I had no interest in being on the inside of one. But I learned what made them work efficiently. I am sure I could cobble up one in any case.

I guess if I have any concerns it would be the amount of room a RMH requires, I am at a premium for space in this house.

I jut don't want to be one of those people that go down a long rabbit trail that is obviously the least efficient to go down. In other words being dead-set on one idea that may not be ideal.

I guess if I have any concerns it would be the amount of room a RMH requires, I am at a premium for space in this house.  

 You don't have to build the pipe bench.  You can build a vertical bell instead.  There are plenty of options, I think, for an situation.  I'm hardly in a position to consult on it, but there are others on this site who are quite knowledgeable.

I took a day or so and researched rocket stoves, but while it was an interesting rabbit path to go down, it was one nonetheless. That is another way of saying I won't be building one. They are scary enough with their intense heat, but in trying to heat water it becomes even more dangerous.The wood/coal boiler I have has some of the same inherent problems, but with a design that was in production for 30 years by that company, it has history and some semblance of safety from its professional design. From what I read it seems the slightest miscalculation and rocket stoves can become exploding bombs at worst, or runaway blast furnaces. I don't want anything like that in my home.

I did however think some more on this project, and I think if I mounted the windmill upon the roof of my house I could simplify a lot of things. With a vertical windmill, I could bring the shaft straight into my boiler room and not have to worry about buried water lines, heat losses, or a host of other complications. I am not keen on mounting one there due to noise and potential vibration, but considering the work that it could save, I think I could build one there and then work out any kinks. That would be easier than dealing with those other issues.

It is generally recommended not to mount any significant wind turbine (either vertical axis or horizontal axis) directly on your house, because the sound of the vibrations of the shaft/bearings/alternator/generator/cavitation heater/etc will make noise that you and everyone in the house will hear.

It may or may not be loud, but it will be annoying.


Also, before you get too far along, consider the legalities and building codes regarding towers and wind turbines.  It would be a shame to invest the time and money and install something, and then get a visit from the nice code enforcement officer who makes you take it down.


I'm not suggesting that as a certainty, or even likely, just a "be sure and find out first" kind of thing.

It is allowed here...sort of.

There was a big windmill company who wanted to put something like 50 windmills along this ridge, and my farm would have gotten three. They would lease the land at $1500 per windmill for 20 years and I was all about that, but the towns people got together and put a stop to it. As one lady said (who lived in town, down in a valley, with 3/4 of an acre of land), "I don't want to look up on my hills and see windmills". And I was like, "Judy, do you pay taxes on those hills?" Anyway no big windmills or their monthly checks, but we are allowed smaller windmills. My Uncle has one but only produces half his power, thus my need to go with wind directly to heat.

But if a billion dollar company determined my farm is ideal for wind, then I should certainly be tapping into it.

But if a billion dollar company determined my farm is ideal for wind, then I should certainly be tapping into it.

 Fair enough.  I'm just playing a bit of devil's advocate, and forcing the RMH discussion, because it did seem that your reasons for not doing it were not as justified as you described them.  

I definitely would not attach a windmill to the house, for vibration/noise issues above described, even barely audible/felt will drive you nuts over time.  Having your heater room in the house will require you to have it close (for reasons you described), but I would not connect it to your house.  There might be regulations about proximity of towers to homes as Troy mentions.  The big company would have massive lobbying power to sway legislators to allow large windmills on your farm.  You may not be able to build one large enough to be worth while. ??  Just wondering.  If you think you can make this windmill powered cavitation heater work efficiently for your in floor system, then do it.  

Hello everybody,

I a new on this forum. I wonder if my own experience could interest some of you since it is exactly related to the starting point of this thread.

I am working, as a hobby, since a few years on a project based on a windmill and the associated devices to heat a building directly using windpower.
Reaching complete heating-autonomy all over the year using an american-farm-type multiblade windmill, a water-stirrer to heat large quantities of water by friction, and a large seasonal-storage
There are many threads dealing already about this solution. What is maybe new in my approach is that I have designed a complete system in the deepest details, and discussed the very specific locations where it could be competitively implemented.

In my attached blog, you will find all the details of the design for the windmill, the stirrer, the specific building, as well as some simulations of autonomy based on a case-study in Dunkerque (France).
The system allows to dynamically and continuously get the highest efficiency of the windmill whatever the wind-speed, thanks to a servo-mechanism also described in my blog.
I also make some comparisons of my solution versus others, like using off-the-shelf water brakes, or electrical resistors for instance.

In reality the most suitable locations to implement such a project are in countries with high geographical latitudes like for instance Scotland, Denmark or Canada in the north, Patagonia or New-Zealand in the southern hemisphere. The reason is that under lower latitudes it would be much easier to use solar-heating-panels to heat such a building.

Anyhow this proposed solution is surely not an economical and competitive solution when compared to common heating systems using fuel or gas. It must be rather considered as a spectacular architectural implementation of what could be done in the field of alternative energies.  The specific building of this project could constitute for instance the flagship of an exhibition-hall dedicated to alternative energy products, and attracting a large and festive audience.

Best regards

My blog: www.windmill-for-heating-buildings.blogspot.com

Marcos Buenijo wrote:Bill, I second (or third) the idea of "stirring" water contained in an insulated vessel for heating. See Joule's work in thermodynamics during the 1800's. Cavitation is not required, but may be unavoidable. Any resistance to the motion of the "paddles" contained in the vessel will transfer energy to the water to raise its temperature. I used to work at an experimental power plant that placed a large "water brake" on the output shaft as a load. The same principle applied there even though it was basically a large hydraulic pump that sent the water through a restriction. On that note, you could drive a vane pump (hydraulic) with the wind turbine sending the discharge of the pump through a pressure relief valve, and contain the whole apparatus within an insulated vessel. If the vessel were pressurized, then this could help minimize any cavitation in the pump.

However, note that wind turbines generally have to be elevated for good performance. Therefore, there would be extreme thermal losses involved in containing the heated water and especially in transferring the heated water to an end use. I expect the losses to be greater than those seen by a good alternator. So, it makes more sense to use the wind turbine to drive an alternator, then send the DC output directly to a water heating element. This is often done as a "dump load" in diversion battery controllers, but in this case one would just connected the alternator directly to the element and call it a day. If it's heat from wind that you want, then this is actually an elegant solution.

Hello Marcos,
I came recently across your old post, and effectively I am working on this type of stirring-water solution to heat a building, since a few years.  I went into details as well for the design of the system, as for the dimensioning to get a full autonomy of heating for a large building. Of course this solution is not competitive compared with a simple fuel boiler. I rather see it as an architectural building open to the public to sensibilize people to alternative energies. This solution is more directed to be implemented in countries with high latitudes and lots of wind, like Scoptland, Canada, Siberia, China, Japan in the North, or Patagonia, New-Zealand in the south. Otherwise solar energy is more straight forward.
I think competitivity is not everything. It could have been a lot more economic to build a mere standard building instead of the Guggenheim Museum in Bilbao for instance.
All the details of my project on my blog:  www.windmill-for-heating-buildings.blogspot.com
All your comments and questions are welcome.

Luke Townsley wrote:It could have enough energy to make steam. It just depends on how much energy you put in. Whatever you put in is what you will get out.

You can't really just put a paddle in a barrel though. The water would swirl with the paddle and not make much friction against the smooth sides of the barrel. You would need to put stationary vanes on the side of the barrel to slow down the water to make more friction.

Perhaps you could adjust the vanes according to the paddle speed to help keep the wind turbine moving at optimal speeds.

The ingenious among us could probably come up with a paddle design that didn't require stationary vanes. Perhaps some sort of screw...

Hello Luke,
I went recently across your exchange of posts 6 years ago on the subject of heating water by stirring it via a windmill. I myself have worked as a hobby on such a project. You may be interested to find all the details in my blog
www.windmill-for-heating-buildings.blogspot.com
Your comments and questions are welcome!

Michael Shumate wrote:About 25 to 30 years ago I designed a brochure (I'm a graphic designer) for a start-up company headed by a former aeronautical engineer who used to specialize in aviation transmissions (I didn't even know that airplanes had transmissions). He said his former enemy was always the heat generated by two sets of veins, paddles, blades rotating at different speeds. It made dangerous amounts of heat at the high RPMs that those engines operate at. After retiring he realized that the same enemy could be used to generate heat directly from motion for domestic use. When I was doing the brochure for him he had developed a system that used an agriculture style windmill with a vertical shaft that transferred the motion of the windmill down to a transmission box buried in the ground. The box was basically a transmission box with one set of blades immobilized. The friction in the transmission fluid made lots of heat that was transferred to water via a heat exchange coil into a tank. The pipes from the windmill to the house had to be well insulated but that was the gist of the whole concept.

I moved from there shortly after doing the brochure so I don't know if the company ever succeeded but I'd love to find out if any such set-up is commercially available. Failing that, I'd like someone's ideas on converting a transmission into a heat generator.

What say ye?

Hello Michael,
Are you still interested in solutions to generate heat directly from windpower ? I have been working as a hobby since a few years on such a solution.
You may be interested to read my detailed project on my blog:  www.windmill-for-heating-buildings.blogspot.com
Your questions or comments are welcome

Jonathan 'yukkuri' Kame wrote:Makes me think of this, though I am prone to disbelieve the over unity claims.
 

 

This is exactly what I was going to suggest. I didn't know if this could be done on a small scale, but heard about this being done on an industrial scale. Its so far the most efficient way to heat liquids, or generate low amounts of heat in general. Using wind to run the pump makes sense, but there would need to be some pretty heavy duty gears to keep the torque and speed right. im sure there is a peak performance that would need to be mantained. one might be able to do this with a bicycle as well, or maybe even a water powered turbine could both capture some water, and then heat it with the uncaptured water.

still i reckon this would be unreliable. possibly best to integrate it with a solar hot water heater, and ample underground storage.

Hey, I like the idea of not using resistor loads to heat water with wind. could you Use a wind generator to power a simple DC motor to rotate a SS plate over another stationary plate with say 5 -10 mils of clearance between th plates while in the fluid creating fluid friction?

I am not really sure, but I think so.

I know at work we generally use river water, filtered and then pumped to our seals to keep the proper pressure for our bearing seals on the hydroelectric runner. As a back up we also have city water. Between the two water sources is check valves, BUT sometimes they fail. When they do, just the two competing flows of water make the pipe so hot that you cannot touch the pipe without getting burned.

Fluid upon fluid makes some serious heat.

Myself, a member of this site anyway, came to this thread by way of a google search. I have little need for electricity as my needs there are light and inexpensive, but heat, now that is a different story. Living on a river with significant flows of 7,000 to 20,000 cubic feet per second, it is possible with 24/7/365 continuous rotation I could generate thermal hydraulics.

I know it can be done with a paddle wheel and baffles, but what if cavitation was also introduced? Would the net heat be increased as air bubbles form and burst?

I know on a hydraulic system, oil driven through the fine orifice of a relief valve constantly, really heats up the oil fast. Think of a log splitter here. What if a river driven paddles drove water through a tiny orifice continuously? When the water temp rose to a certain temperature, it would be pumped off for use such as domestic hot water.

Bill Kearns wrote:For a long time I've been cogitating (that's what old codgers do ... cogitate) on determining the best method to turn kinetic energy directly into heat ... specifically how to directly heat water with wind energy.  Most of the ideas I've seen involve generating electricity to power resistance heating elements, but this is SO inefficient!

This initial premise of this entire discussion that resistance heating elements, are "SO inefficient" has generated an entertaining discussion with some very creative ideas.
The truth is electric heating elements are just resistors that essentially add friction to electric current thereby creating heat.
They are extremely efficient in that regard. They are all the friction you need.
Permanent magnet generators are bout 85 % effeicient.
The cost of a generator and a resistor has to be substantially less than any of the above approaches.

Could you get more heat out of the electricity. Yes, by using a heat pump. But heat pumps work by moving heat not creating it except of course the amount they add due to friction!
I

J McKravits wrote:This initial premise of this entire discussion that resistance heating elements, are "SO inefficient" has generated an entertaining discussion with some very creative ideas.
The truth is electric heating elements are just resistors that essentially add friction to electric current thereby creating heat.
They are extremely efficient in that regard. They are all the friction you need.
Permanent magnet generators are bout 85 % effeicient.
The cost of a generator and a resistor has to be substantially less than any of the above approaches.

Could you get more heat out of the electricity. Yes, by using a heat pump. But heat pumps work by moving heat not creating it except of course the amount they add due to friction!
I

This is very true. It is one of the few exchanges in energy where you get a one for one deal.

I work at a hydro facility and we use a lot of electric heating units in the winter and it only makes sense. Producing 16 megawatts from a renewable source, it is a very responsible way to heat with both an environmental, and fiscal reasoning.

I ran into this once when I considered taking my back up generator, and plumbing the coolant lines of my engine into my radiant floor heating system so that when it was running to provide electricity for my house, it would use some of the mechanical heat of the engine to also warm my house. There is nothing wrong with that, but it was also kind of silly.

To get the right frequency (hertz) I have to run my engine at a certain RPM which for means I am making 20 KW. It would be a whole lot simpler to just plug in electric space heaters than spend tons of money plumbing cooling systems into my radiant floor heat. I am making excess electricity so why not just convert that into heat instead.

Myself I could never figure out why massive greenhouses were not built beside powerhouses. I worked at one that only produced 31 megawatts and yet we lost 350,000 gallons of water a year to evaporation and heat. A greenhouse could be heated for free if they just tapped into what a powerplant vented to atmosphere, I am pretty dumb but free generally tends to be a great business model.

Well the most simple way of turning wind energy to hot water is to just turn a water pump shaft and circulate water through a closed system such as an insulated tank.  All of the shaft power of the pump that moves the water is turned to heat.  You can actually buy hot tubs that have no heater.  They just cycle the pump on and off to heat and maintain water temperature.  My hot tub now has a heat pump.  However, if I forget to turn the high speed water pump off, the hot tub can hit 55 degrees C or 131 degrees F.

Paul Crumpler wrote:Well the most simple way of turning wind energy to hot water is to just turn a water pump shaft and circulate water through a closed system such as an insulated tank.  All of the shaft power of the pump that moves the water is turned to heat.  You can actually buy hot tubs that have no heater.  They just cycle the pump on and off to heat and maintain water temperature.  My hot tub now has a heat pump.  However, if I forget to turn the high speed water pump off, the hot tub can hit 55 degrees C or 131 degrees F.

Water pumps need a source of energy to power them. Most are air cooled electric motors. Unless the electric motor that powers the pump is cooled by the water your trying to heat, you'll lose a lot of energy.

Hi Paul,

Welcome to Permies.