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direct heat from wind turbine

  • 05-08-2012 1:54pm
    #1
    kenskool
    Registered Users, Registered Users 2 Posts: 39 ✭


    Is it possible to heat water directly from a wind turbine generating 3 phase electricity? Our turbine can produce up to 1.5 Kw at voltages up to 400V.We do not want to convert to dc if possible and are concerned that with the varying wind speeds the voltage fluctuates widely.Would a 400V immersion be available and would it heat at all at the lower voltages ?Any advice appreciated.


Comments

  • #2
    quentingargan
    Registered Users, Registered Users 2 Posts: 1,627 ✭✭✭quentingargan


    This is problematic because the load you want to apply to a turbine isn't constant. As the turbine speeds up (and its voltage rises) the load that should be applied is exponential.

    Certainly, if you apply the load permanently, the turbine will find it hard to get started, and in lower winds (say 4 or 5m/sec) you would find that the load which was appropriate to 400V and 1.5kw would stall the machine.

    The easiest solution would be to have a maximum voltage relay switch on the load above a certain voltage, but that relay would be worked hard at low revs as the power went on and off, causing the voltage to swing. You would need a relay with very wide hysteresis settings.

    A more appropriate route would be to use a DC load switched by an IGBT using pulse width modulation to vary the load as the voltage rises. I have tested this and it can work quite well, but the control system is quite complex. Depends on how much of a hobbyist you are.

    The main reason why this is seldom developed is because heat is a relatively cheap form of energy compared to electricity, so it is usually more cost effective to stick in an inverter and use the power as electricity.


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