Questions addressing small scale power generation

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  • GreenAce92GreenAce92 Registered Users Posts: 17
    Re: Questions addressing small scale power generation

    Oh man! How awesome! THE RAT! Ladies and gentlemen I give you... THE RAT!

    Hahaha, how crude it is. I didn't know these were used until now. I thank you for this new device/knowledge.

    What about the main jet turbines? Do they not "free spin" in the event of a power loss? Do they close off the doors. I thought when I first read your post that they ejected the jet engines ha!

    Jet engine! Phenomenal. Saw a 747 making massive contrails today on a clear blue sky.

    inetdog, thank you for the explanation. I understand.

    When you think about "heat", let's sort of go off topic here... In space "heat" is in the form of electromagnetic radiation right? And it is either extremely hot, or extremely cold due to the absence of an atmosphere so... in regards to a "Heat Engine" what exactly are we talking about here? I mean, do humans "feel" heat because their skin cells or nerve cells are being excited or energy is being added to them by radiation?

    When you see depictions of heat, you always see these "waves" I wonder if it is because of the "wave appearance seen when rising heat from for example a fire changes the speed of light and you can see a wavy figure on the ground from something "invisible" the "heat"

    I may have confused some topics there but I noticed that today on a barbecue grill
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Questions addressing small scale power generation
    GreenAce92 wrote: »
    What about the main jet turbines? Do they not "free spin" in the event of a power loss? Do they close off the doors. I thought when I first read your post that they ejected the jet engines ha!

    When you think about "heat", let's sort of go off topic here... In space "heat" is in the form of electromagnetic radiation right? And it is either extremely hot, or extremely cold due to the absence of an atmosphere so... in regards to a "Heat Engine" what exactly are we talking about here? I mean, do humans "feel" heat because their skin cells or nerve cells are being excited or energy is being added to them by radiation?

    When you see depictions of heat, you always see these "waves" I wonder if it is because of the "wave appearance seen when rising heat from for example a fire changes the speed of light and you can see a wavy figure on the ground from something "invisible" the "heat"

    I may have confused some topics there but I noticed that today on a barbecue grill

    Well, here is my last contribution for the night.

    1. the depictions of heat waves are because the heated air has a different index of refraction than the cooler air and acts like a lens to objects on the far side of it. But the hot air currents move around (rather like a candle flame moves back and forth) and so the lens is constantly moving and we see the objects in the distance appear to be moving around. Without an optical reference in the background, you would not notice anything. Well, actually the difference in air density lens effect can also cause uneven shadows on a uniform surface on the far side if the sunlight is passing through the heated air. This is called the Schlieren effect. Google it if you find it intriguing.

    2. The skin cells that sense heat react to two things, absolute temperature (important for pain reaction, etc.) and to increases and decreases in skin surface temperature. The latter is more sensitive, but has less of a calibration to actual temperature. Like the difference between telling which note is higher than the other but not having perfect pitch.

    3. No idea what they do with the jets when an engine fails, but no useful power is produced from ram air drive through the turbines, so it does not matter much except for the drag that results.
    SMA SB 3000, old BP panels.
  • GreenAce92GreenAce92 Registered Users Posts: 17
    Re: Questions addressing small scale power generation

    Sorry to bring back an old thread

    I was just wondering why most of the commercial generators that I see are vertically oriented?

    If an object does not displace height then is there work done on the object? Despite that it is spinning?
    The answer might be really simple but I have seen spiral shaped wind turbines like the one featured in the movie "Water World" though I haven't seen these in person. It would seem that this wind turbine design is based on this idea of no vertical displacement eg. the blades don't go up to fight gravity... although since symmetry is involved and when the blades go back down with gravity then maybe there is no net effect of gravity on the turbine?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Questions addressing small scale power generation
    GreenAce92 wrote: »
    Sorry to bring back an old thread

    I was just wondering why most of the commercial generators that I see are vertically oriented?

    If an object does not displace height then is there work done on the object? Despite that it is spinning?
    The answer might be really simple but I have seen spiral shaped wind turbines like the one featured in the movie "Water World" though I haven't seen these in person. It would seem that this wind turbine design is based on this idea of no vertical displacement eg. the blades don't go up to fight gravity... although since symmetry is involved and when the blades go back down with gravity then maybe there is no net effect of gravity on the turbine?

    You've got your horizontal and vertical confused. A standard wind turbine is considered "horizontal" based on the shaft orientation. Hence the terms Horizontal Axis Wind Turbine (HAWT) and Vertical Axis Wind Turbine (VAWT).

    The horizontal ones are far more efficient because the blades don't have to turn back in to the wind the way a VAWT does. Schemes to overcome this shortfall only result in the blades spinning in very turbulent air one way or another.

    The need to "overcome gravity" lifting the blade on one side is offset by gravity pulling it down on the other.
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Questions addressing small scale power generation
    The need to "overcome gravity" lifting the blade on one side is offset by gravity pulling it down on the other.
    And even the occasional oddball single blade wind turbine uses a heavy counterweight close to the axis to balance the rotor.
    Whether you have a two, three, four or five blade turbine, each blade is "lifted" by the weight of the blade(s) on the other side at that exact moment. Then when that blade goes down it takes its turn helping to lift the opposite blade(s).
    SMA SB 3000, old BP panels.
  • GreenAce92GreenAce92 Registered Users Posts: 17
    Re: Questions addressing small scale power generation

    Thanks for answering my questions thus far

    I have some more

    I was kind of foolish not thinking about the construction of a simple $20 window fan as I tried to measure the EMF generated as the blades spun due to the wind.
    I was later told by some people online that the fan used a wire based design so no current generated lorentz force?

    Anyway probably another pointless question but what would be the benefits of using a non-magnet type generator? Perhaps one set of wires are energized by say solar panels feeding them. Sounds like a self-defeating design but I'm curious if other designs exist that don't rely on magnets. I mean, is there no other way?

    Also, what benefit could be had if a wind turbine (horizontal axis) was designed so that the blade tips were magnetic and say a ring was on the outside of the wing tips. Here's a design example.

    The design itself isn't the issue at least in terms of how it would be physically built. I suppose the real problem is the discontinuitiy in the coils.

    temporary-97.jpg

    I think I will find as I have in my other drawings that there are some obvious inherent flaws and because my educational background is so bad, I make the mistake of drawing things without knowing that they are alreayd useless. But, if you like, entertain me. Tell me all the problems becides centroid.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Questions addressing small scale power generation

    The main advantage I see in using an electromagnet instead of a permanent one is the ability to vary the intensity of the magnetic field: with a "fixed" magnet there is a minimum amount of force needed to overcome the inertia and begin generating power. Without it, the turbine can start moving and the resistance of the magnetic interplay can be varied allowing some output at lower speeds. ("Speed" may be an inaccurate term here; torque might be more precise over a range of blade designs.)

    The tradeoff (and there is always one for any design of anything) is that as the speed increases it becomes less efficient due to having to feed some generated power back to maintain the exciter field.
    Also, what benefit could be had if a wind turbine (horizontal axis) was designed so that the blade tips were magnetic and say a ring was on the outside of the wing tips. Here's a design example.

    This has actually been done. The downside being the greater amount of rotating mass at the end of what are essentially levers on an axle. With just blades, if they flex or bend a bit it isn't particularly damaging. But if you put the magnets and coils out there it is easy to lose proper alignment with flexing under strain. Given enough wind it's a sure-fire catastrophic failure. The upside is that you have a much greater area to work with for generating power. Although that advantage becomes nil once you get past a certain blade-area-to-magnetic-field-capacity ratio (not enough blade to spin the turbine against the resistance of the interacting fields).

    Biggest problem with wind turbines in general is that wind speed varies, and the best design for one speed isn't the best for another. You always have to compromise somewhere.
  • GreenAce92GreenAce92 Registered Users Posts: 17
    Re: Questions addressing small scale power generation

    Thank you for the sincere response

    I suppose while I'm at it, here's another assinine design

    transient-turbine2.png

    transient-turbine.png

    My engineering professor at the time whom I showed it to, told me that I had a good idea of fluid dynamics though I think in retrospect he was just being kind and trying to amuse me.

    I have considered this design stupid as well because the magnets don't even properly interact with any wires to create force.'
    The idea also was to use fluid bearings to keep the turbine "suspended" if you will or free of drag.
    Also the my idea of fluid flow I think is bad. The idea is that water flows faster around the skin of the pipe or edges (this is a turbine design) still I was proud of my drawing haha. Perspective!

    I'm taking Modern Physics again, ha! Life has gotten me distracted (it's these two things between my legs)

    At least I may be able to apply the knowledge I am learning to some wind turbine designs or something along the lines of power generation.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Questions addressing small scale power generation

    Why not go whole-hog with magnetic levitation to reduce the bearing friction? :D

    Trouble with fluid bearings is the variation in viscosity most fluids have with change in temperature. In essence, many bearings are "fluid" in that there is a thin layer of lubricant between the two surfaces. As with everything else this presents both problems and possibilities.

    I wish you could find a museum of some of the old dynamo designs and see what has been tried over the years, preferably with educated write-ups on how they worked and what their failings were. We've come a long way from Michael Faraday's magnet and coil!
  • GreenAce92GreenAce92 Registered Users Posts: 17
    Re: Questions addressing small scale power generation

    Cariboocoot,

    I am happy that you are responding without anger. I had feared that my last post would have been considered "of poor taste"

    I suppose at the heart of all great things is a lot of planning

    There is an exception I can think of, the Russian NK-33 closed cycle rocket engines which were perfected by iteration and still somehow far surpassed any American counterpart 10 years later.
    That's what I took away from a documentary anyway. Also what about money? What does a great invention stand against greedy pigs? What is worth more? The welfare of one man vs. the world?

    hehe history can answer that question

    Thank you for your thoughts on my posts

    I am curious if there will be any other form of "energy" technology. It seems that electricity dominates.

    I would like to see the day when I can take any piece of matter and turn it directly into energy.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Questions addressing small scale power generation

    Electricity dominates these days because it is so flexible. You can generate it innumerable ways, store it many ways, send it down wires, and when it gets to the end make it light, heat, turn, etc. You can well argue the various levels of efficiency achieved at any one of those stages and sometimes less efficient choices are made out of ignorance but more often out of practical economics of the moment or the "good enough" criterion.

    In essence electricity is energy: of the four basic forces of the universe electromagnetism is one. We're still having a bit of trouble with the other three, particularly gravity which is a real downer. :D

    (For anyone who fell asleep during high school physics the other two are the strong atomic force and the week atomic force.)

    It is always wise to look back at what has been done to avoid making the same mistakes again. By the same token revisiting past endeavours can sometimes spark new ideas.
  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Questions addressing small scale power generation

    here is a larger scale unit, #2 on the list http://www.nrcan.gc.ca/science/story/3616
     
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    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
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