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Forum Index : Windmills : punch some holes in my idea
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| Lortan Newbie  Joined: 27/07/2009 Location: CanadaPosts: 7 |
First off - GREAT site. I've been killing time on this site for the last week now and I think this is the place to get the info and help I need. I have been wanting to get into building my own windmill for a few years now but I have always run into some thing or another that stops me. After finding the F and P info here I have renewed enthusiasm for building a windmill. I live in Rural Edmonton, Alberta Canada and the wind is almost constant here so I am positive a windmill will work here. Being primarily OIL country, there is not too many people here thinking about green energy. Anyways, here is my idea: I get myself a f & p motor or similar and build myself a windmill using some plans/ideas gleaned off this site and others. Rather than putting the power made into batteries or grid tie-ing I put it straight into an electric hot water heater. I then run our pool water through the hot water tank constantly. If the wind blows it heats the pool. If not then no big deal. I figure that this way I do not need any inverters, batteries etc. Just wires from the windmill to the hw heater. Now on one of the pages of info about the f&p motor you show how to convert it to dc. Would this need to be done? It is my thinking that an electric element does not matter if it is powered by dc or ac and so long as your voltage is lower than the rating on the element all will be fine. Am I right or am I totally nuts? |
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| davef Guru  Joined: 14/05/2006 Location: New ZealandPosts: 499 |
A workmate does the seem thing here in NZ. Have you worked out "ever-how-many" watts you are going to generate and what savings that will result in? |
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| KiwiJohn Guru Joined: 01/12/2005 Location: New ZealandPosts: 691 |
Hi Lortan I agree with your thinking and I believe you are right in everything you have mentioned. In fact if I was to do a wind power project where I live I would likely devote the entire output to water heating much in the manner you propose. If I understand correctly converting electric energy into heat is 100% efficient (as all waste is heat too). Best wishes for the project John New Zealand |
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| Lortan Newbie Joined: 27/07/2009 Location: CanadaPosts: 7 |
I'm not really looking to save any money so to speak. I just want to be able to justify the time, energy, and costs associated with setting up a windmill. I just did a quick GIS for workmate and come up with a pile of Black and Decker stuff. Obviously this is not what you are talking about. What is a workmate? Kiwi - what about the conversion to dc? Would I be better off just using the f&p as is or would it be better to convert it to dc? |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5124 |
"workmate" is southern speak for a person you work with, as apposed to "mate", which can be just about anything including your best friend, your dog, even your car, but strangly never your "missus". The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| davef Guru Joined: 14/05/2006 Location: New ZealandPosts: 499 |
Just use it as it is, why waste the energy dropped across the rectifier? What is the max voltage you expect to get? Maybe a couple of jug (aka kettle) elements in series to handle the maximum expected voltage would do the trick. Cheers, Dave |
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| KiwiJohn Guru Joined: 01/12/2005 Location: New ZealandPosts: 691 |
Lortan, there is no advantage in DC over AC for heating, in fact the conversion (i.e. rectification) wastes a significant. |
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oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
If it were me, I would use DC. Three phase alternator means using three elements if you wish to use AC for heating. If you do use AC and three elements, you get to be able to switch the three in sequentially, which is the best way to try and match the load. At low winds, use one element from 1 phase, as the wind picks up, and power increases, switch in second phase, in full winds, use all phases. With DC, you can use a single element, but you can still switch in the phases to the rectifiers sequentially. Either way, you will need to control how much load is being driven as the wind changes. You can also use series HV capacitors. This is possibly the easiest way to drive resistive loads. It solves startup, and power increases more than linear as the frequency and voltage rise...... tending more towards ideal than any other simple way I think. It is not as simple as driving batteries, but more power is available as the load matching is capable of better synergy. Which ever way you choose, furling will be critical, as the torque does not rise as steeply as with traditional battery charging. The diode losses in HV power systems is inconsequential... .6v out of several hundred volts at low amps is not worthy of consideration. I assume you will be running this at mains voltage .... so you can use normal elements, and keep the current down. ...........oztules Village idiot...or... just another hack out of his depth |
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| Lortan Newbie Joined: 27/07/2009 Location: CanadaPosts: 7 |
Ok so it sounds as though this is a do-able project. Now I know enough about electricity to be dangerous. I understand single and three phase power, ac and dc power but when it comes to delta wiring, diodes, rectifiers, switching and capacitors my eyes begin to glaze over. I plan on using an off the shelf electric hw heater - say about 10 gallon size - something you would find in a travel trailer to keep the costs down. So if I were to keep the basic wiring the same on the motor I would need three hw heaters? One for each phase. But if I change the motor to dc as shown here on the site then 1 hw heater would be fine right? It has been a while since I looked at one of these units, I'm sure it has only the one element. (I installed a hw heating system 2 years ago in our house and used the boiler to supply the domestic hot water) Maybe if this works well I could supplement my heating costs with a couple of windmills. 
As for controlling the speed of the wind mill I am thinking of a couple of ideas - having the unit tip up out of the wind would probably be the easiest I would expect. Maybe have a disc brake also. I used to be a manager in a injection molding shop and we did a quote for a company here that made nylon fan blades for the big caterpillars up at Ft.McMurray oil sands. They were about 3' long and attached to a system that you could adjust the pitch of the blade to allow you to reverse the flow of air to blow the rads out. Maybe I could get a used unit from these guys. Or even just get some blades to try out. I remember seeing a governor system on steam engines that had two balls that would slow the unit down - has anyone tried this out on a windmill? My head is spinning faster than a windmill right now. I'll have to stop before i get dizzy. Sorry. ADHD is kicking in again  |
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readyakira Senior Member  Joined: 17/07/2008 Location: United StatesPosts: 114 |
I love this idea, and I may also work a project like this with all the F&P and Oasis drives I have. Myh biggest problem is lack of tools to construct these projects, b ut I do have a 50gal dual element water heater to play with. What about Ground fault protection? I would think this would need that due to the possibility of higher voltages blowing an element and that may not be fun if you are in the pool at the time. The model number is EE2H50RD045V on the water heater I have and it has sensors to monitor temps that could maybe incorperated into the system to prevent a boilover situation. Don't you think Free/Renewable energy should be mandatory in new buildings? |
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Greenbelt Guru Joined: 11/01/2009 Location: United StatesPosts: 566 |
Lorton; I did some Googleing for you, The Hot water Tank of the size you mention have a power requirement of 1500 - 1600 watts. I also checked on a couple of 6 gallon tanks. The one's I looked at were also in that range. This is good. The F&P single stator will work at full capacity into this load. A useable Turbine will have a diameter of 2 plus meters. A 2 meter blade - ( 78") will sweep an area of 33.16 Sq. Ft. Wind pressure is 8 Oz. square ft. at ten Miles Hr. (13.4) KMH. (33.16 Sq. Ft. X 8 Oz.= 265.2 / 16 = 16.5 pounds of wind force. The area of the turbine blades is only a fraction of the square area, so it is important to have a windmill sized for the torque requirements of a generator. A 3 foot multi blade fan will intercept 7.06 Sq. Ft. of wind. 3.5 pounds. Note: This is not a value of shaft Torque. The speed control Governor on the Steam engine is connected to the steam pipe going to the cylinders , It controls the steam valve. Inside your Lawnmower engine is a similar device that controls the throttle valve. Sorry about the holes in your plan. but HEY! the' re little ones. We all got Em. ! Time has proven that I am blind to the Obvious, some of the above may be True? |
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| Lortan Newbie Joined: 27/07/2009 Location: CanadaPosts: 7 |
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GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Trying to put power from a windmill alternator directly into heaters is OK if you are able to match the windmill output power curve to the loading power curve. resistive heaters have a squared power relationship to applied voltage. The cubic power of the wind to windspeed and the windmill alterator/rotor/furling relationship to windspeed needs to match the wind energy. Most systems of this type require underloading to prevent rotor stalling problems, and good furling top prevent runaway in high winds. A windmill seems to be reasonably good at finding a match to the loading. First attempts are best with overloading, and gradually reducing the loading to observe windmill behaviour and outputs. Good furling for higher winds is a must. Gordon. PS: AC Series Cap arrangements do give better power matching, but these need to be well matched for frequency and power handling requirements. A have made a picaxe08M cct that gives a 7stage loading into a 240VAC heating bank. become more energy aware |
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| Greenbelt Guru Joined: 11/01/2009 Location: United StatesPosts: 566 |
Moved to Changing pitch. Time has proven that I am blind to the Obvious, some of the above may be True? |
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| Greenbelt Guru Joined: 11/01/2009 Location: United StatesPosts: 566 |
Lortan; A usable Turbine will have a diameter of 2 plus meters. The truth is I don't know whether a blade is all of it or half or a third or? I have seen it both ways. In any case, The total swept area should be close to two meters Minimum. Sorry for the confusion.  Time has proven that I am blind to the Obvious, some of the above may be True? |
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| oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
A blade running at it's ideal TSR, will use up all the air in it's swept area. It is not the "blade surface area" that counts, it is the entire swept area. As a concept of what is going on: If the blade is not using all the air in it's swept region, it will increase speed until it does. When the blade is following in the wake of the blade in front of it, and cannot extract any more energy from the soon to be spoilt air, it will not accelerate any further. So if you add more blades, you must necessarily slow down the rotation, as the air is spoilt in more places in the circle, so moves less distance before running into turbulence from the preceding blade.....(less rpm, but more torque) just another way of looking at it. If it was only getting power from it's surface area instead, this would not hold true... but rather the opposite I expect..... more blades..more area... more power. This does not happen..... more torque at lower speed, but not more power. I would not consider less than 4m diameter for this kind of project if I was to expect any notable heating value. In that case, I would not use a F@P either. The money you are talking for one of these units over there would lead me to build an axial for that kind of money. The axial will give you more flexibility with your design, good power at lower RPM (bigger diam=less rpm) and a braking system built in.... so less chances of runaway. Runaway is a problem with resistive driven loads. As Gordon points out, your wind power is cubic, but the resistive load is squared. So you will be prone to stall at low rpm..... then match at medium rpm, and runaway with excess power at higher rpm. Thats why you need staged switching.... or capacitive coupling. Zubbly did some good testing with this kind of thing (cap coupled heating) on fieldlines... Dinges I think did the maths for the cap values.... will find the link perhaps if you like. ..........oztules Village idiot...or... just another hack out of his depth |
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| petanque don Senior Member Joined: 02/08/2006 Location: AustraliaPosts: 212 |
Wouldn’t 1-200 dollars worth of Polly pipe on the roof do a better job of heating the pool? If it would be better to have a separate pump for the heater or use the pool pump would be the only question. How many Kw hours of electricity would be needed to heat the water in the pool by 1 degree? 
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| Lortan Newbie Joined: 27/07/2009 Location: CanadaPosts: 7 |
I already have the solar heater deal set up on the pool. I am more looking for an excuse to set up a windmill. The main mindset here in Alberta is oil, oil, oil, and oil. I don't have much of a problem with that as it does make the economy here pretty good but it makes for difficult when you are trying to make free energy. The energy board here just waived the $1800 dollar application fee to allow grid tieing but we are a long ways from making it feasible. Here is some info hxxp://www.auc.ab.ca/rule-development/micro-generation/Pages /default.aspx if you want to make your head spin faster than your windmill read the micro generation guideline. All I can see is red tape and 45 years trying to recoup costs from the initial install. I would like to get into making my own power via wind solar etc but I want to do it bit by bit. I plan on learning by heating the pool for the family, - no batteries. Then maybe after if I get that working nicely maybe I'll try getting my natural gas hot water heating in the house supplemented with an electric boiler run by a wind mill. I like the idea of using hot water as my batteries. Some of the big costs that I see in producing your own power is the batteries and the inverters and control systems. If I can get away from that I will be better off I figure. |
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| Dinges Senior Member Joined: 04/01/2008 Location: AlbaniaPosts: 510 |
[quote=Petanque Don]How many Kw hours of electricity would be needed to heat the water in the pool by 1 degree?[/quote] Q= m * C * deltaT 1kWh equals 3.6 MJ (3.6*10^6 J), so Q=3.6 * 10^6 J m: the mass of the water that needs to be heated. Let's assume a modest swimming pool of size 5*3*2 m, so 30 m^3, equal to 30.000 liter of water, which weighs about 30.000 kg: m=30.000 C=specific heat of water, 4.2*10^3 J/kg/K deltaT = temperature rise (in K, and in this case deg. C too) So 1kWh of energy would heat the 30.000 liter of water by: 3.6*10^6 = 30000 * 4.2*10^3 * deltaT --> deltaT=0.0285 C The temperature of the water would rise by 0.0285 deg. C for each kWh of electrical energy you put into it as heat (ignoring other heat gains and losses). You'd do *very* well if you could generate 1kWh every day with the current small generators that are being discussed on this forum. Using electricity for heating is a great waste in most cases. Electricity is one of the highest grades of energy available: it can be put to work in many different ways; on the other hand, heat is the lowest grade of energy (all energy finally ends up as (waste) heat). Using electricity to generate heat is a waste of precious resources. [quote=Lortan]when you are trying to make free energy.[/quote] 'free energy' is a term I wouldn't use to discuss wind or solar energy. 'Renewable energy' is a more accurate description. And it is anything but free. [quote=Lortan]I am more looking for an excuse to set up a windmill. [/quote] [quote]I would like to get into making my own power via wind solar etc but I want to do it bit by bit.[/quote] Try getting the shed or garage powered by windenergy instead? Seems like a more sensible solution to me. That 1kWh of energy could go a LONG way in getting the garage or shed off-grid. And with some care, the fridge and freezer in the kitchen as well. Getting a part of the house off-grid would also greatly aid in the education of the most important aspect of switching to RE: conservation. How many kWh does your home use every day? I'm now down to 2.5kWh/day (a quarter of the use of 2 years ago) and intend to cut that in half again. When you're trying to power one room of your house with renewable energy, you'll quickly find out how important conservation of energy is. No energy you will be able to generate yourself will be cheaper than grid power. So conservation always makes sense, but especially when you're installing an expensive RE system. Peter. |
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| Lortan Newbie Joined: 27/07/2009 Location: CanadaPosts: 7 |
Ok I'm back. I went with the axial flux from Hugh Piggot. I ordered his plans and got to work. I have to say that the plans are great and I managed to make a from scratch 4' turbine in about 1 week. I went with the small one first to get the hang of it and see a finished product before I ran out of gas so to speak. His instructions for carving the blades are quite good. I will attach pics of it if anyone is interested. I have scrounged around my fathers farm and got myself a 20' tower/boom from an old crane and a 12' chunk of schedule 80 pipe that I will weld to the top of the crane/boom. I was thinking of attaching the tower to the frame of an old farm truck I have here. Has anyone here ever tried this? The truck is a 1950 chev grain truck without the dump box. I was thinking that I could move the truck around the yard to get the best location for wind. On a small turbine like this I would doubt the wind would be strong enough to tip it over but then what the heck do I know? My next problem is trying to come up with a system to dump the power from the mill to a hot water tank. From what I know now is that I cant directly wire from the mill to a heating element because the blades will never start turning. Is there any quick and easy ways to do this? |
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