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Electromax efficiency question

Discussion in 'Plumbing and Central Heating' started by MM33, 3 Jan 2018.

  1. MM33

    MM33

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    Hi all,

    I own an electromax electric boiler.
    According to its datasheet which can be found here:
    https://www.heatraesadia.com/-/medi...atraesadia_datasheet_electromax_lr_output.pdf

    It has "99.8% boiler efficiency and integrated economy controller"
    However further down, in the same document there is:
    Seasonal space heating energy efficiency class D
    Seasonal space heating energy efficiency (%) 37

    My question is, out of every 1 kwh input, how much heating (in kwh) is produced ?

    Thanks.
     
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  3. stem

    stem

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    With regards to heating, electricity is generally considered to be 100% efficient, you put in 1kW of electricity and you get 1kW of heat out. I guess the 99.8% is less 0.2% that isn't converted into heat and is instead used by the controls to operate the system.
     
  4. MM33

    MM33

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    Thanks Stem,
    What is "Seasonal space heating energy efficiency" ? and why is rated D if it is 99.8% efficient ?
     
  5. endecotp

    endecotp

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    Because it's electric.

    I suspect, but do not know, that the 37% efficiency is related to the hypothetical typical efficiency of the (gas-powered) power station providing the electricity. So it's in some sense comparable with the efficiency of burning the gas yourself in a gas boiler to make heat directly.
     
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  7. stem

    stem

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    You didn't ask that ;)

    To be honest I thought you would ask that, and I would want to know, but unfortunately I can't tell you.
     
  8. Terrywookfit

    Terrywookfit

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    Generating and transmission losses.?
     
  9. echoes

    echoes

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    That appears to be correct. The rather opaque calculations assume that the electricity generation is 40% efficient, and combined with other factors, we get to 37%.

    Although a modern combined cycle gas fired power station is significantly more efficient than that.
     
  10. MM33

    MM33

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    Thanks everyone.
     
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