Running costs Dyson hot/cold fan

13567

Comments

  • aliasojo
    aliasojo Posts: 23,053
    First Post First Anniversary Combo Breaker
    Forumite
    I 'played' with one of these in Currys last week. I loved it. It was small, neat and imo very powerful. I was amazed at the force of (very) hot air that was expelled by it / through it.

    If I had plenty money I'd have one of these in a heartbeat, you can shove your £10 Argos jobs. It's kinda like saying a Reliant Robin will get you from A to B so why pay more for a Ferrari? There's no comparison. :D
    Herman - MP for all! :)
  • Andy_WSM
    Andy_WSM Posts: 2,217
    First Anniversary First Post Uniform Washer Rampant Recycler
    Forumite
    DragonQ wrote: »
    Nonsense. Electrical elements emit light, have you never looked inside an electric oven?


    Clearly not as some of the energy is emitted as light.


    No, your statement violates the law because you are saying that something that emits light is somehow also emitting all the energy it consumes as heat.

    Oh dear! Back to school for a physics lesson DragonQ!
  • Cardew
    Cardew Posts: 29,036
    Name Dropper First Anniversary First Post Rampant Recycler
    Forumite
    DragonQ wrote: »
    Nonsense. Electrical elements emit light, have you never looked inside an electric oven?


    Clearly not as some of the energy is emitted as light.


    No, your statement violates the law because you are saying that something that emits light is somehow also emitting all the energy it consumes as heat.

    Is this post meant to be serious?
  • DragonQ
    DragonQ Posts: 2,193
    First Anniversary First Post
    Forumite
    Andy_WSM wrote: »
    Oh dear! Back to school for a physics lesson DragonQ!
    I have a masters degree in physics. None of you has attempted to explain why what I have said is wrong. Unless we're talking about different things, what I have said is correct.
  • rogerblack
    rogerblack Posts: 9,446 Forumite
    DragonQ wrote: »
    I have a masters degree in physics. None of you has attempted to explain why what I have said is wrong. Unless we're talking about different things, what I have said is correct.

    It's a remarkably useless distinction though.
    Unless the room is open to the sky - essentially all of the IR light emitted by the elements will be absorbed by the room, and converted to heat.
    As will most of the noise.
    You missed out vibration and gravitational radiation by the way, as well as radiated EM, and ...

    However, vastly overshadowing all of these is the loss in the cable back to the meter - which may comfortably exceed a percent in some cases.
  • DragonQ
    DragonQ Posts: 2,193
    First Anniversary First Post
    Forumite
    Plus of course the electricity generation in the first place isn't going to be 100% efficient. There's a reason electric heating is expensive.
  • Cardew
    Cardew Posts: 29,036
    Name Dropper First Anniversary First Post Rampant Recycler
    Forumite
    DragonQ wrote: »
    I have a masters degree in physics.

    Really?

    Is that also a serious post?

    That 'lost' energy - where exactly does it go?

    It is a pity Albert Einstein is dead, he would be interested that you have proved him wrong.
  • DragonQ
    DragonQ Posts: 2,193
    First Anniversary First Post
    Forumite
    Cardew wrote: »
    Really?

    Is that also a serious post?

    That 'lost' energy - where exactly does it go?

    It is a pity Albert Einstein is dead, he would be interested that you have proved him wrong.
    What do you mean where does it go? Are you talking about the fact that pretty much everything turns out as heat in the end? If so, that has nothing to do with the efficiency at the point of the device (which is why I said above we may be talking about different things).

    However, if you're not talking about the energy transfer of the device itself and you're including things "later in the chain", as it were, you should also include everything earlier in the chain too, as rogerblack and I alluded to. Thus, nowhere near 100%.
  • Cardew
    Cardew Posts: 29,036
    Name Dropper First Anniversary First Post Rampant Recycler
    Forumite
    DragonQ wrote: »
    What do you mean where does it go? Are you talking about the fact that pretty much everything turns out as heat in the end? If so, that has nothing to do with the efficiency at the point of the device (which is why I said above we may be talking about different things).

    However, if you're not talking about the energy transfer of the device itself and you're including things "later in the chain", as it were, you should also include everything earlier in the chain too, as rogerblack and I alluded to. Thus, nowhere near 100%.

    Methinks you are wriggling!

    This is what I stated:
    Ten 100watt bulbs using, say, 1kWh will produce exactly as much heat as any form of electrical heater - including fan heaters - using 1kWh.

    Which you stated was 'nonsense' because bulbs produce light.

    A kWh is a unit of energy equal to 1000 watt-hours or 3.6 megajoules.

    Given that energy can neither be created or destroyed(according to Einstein) where is the energy to the tune of 3.6 megajoules consumed by the bulbs 'lost' in your redefinition of the laws of thermodynamics?

    A halogen heater uses light as the delivery method to provide the heat. A halogen heater doesn’t just heat the air around you, it heats everything the light rays land on.

    So by your definition a halogen heater, because it is emitting light, must be less efficient than, say, an oil filled radiator.
  • DragonQ
    DragonQ Posts: 2,193
    First Anniversary First Post
    Forumite
    edited 27 May 2013 at 11:00PM
    I have no idea what you're going on about. Energy is considered "lost" or "wasted" when it is not in the form you want. A lightbulb is designed to produce light, so any energy it releases in the form of heat is considered waste. There is no redefinition here - if only 80% of the energy consumed by the bulb is emitted as light then it is considered 80% efficient. Not sure why you're struggling with this concept.

    If a halogen heater is emitting light then of course it is not 100% efficient. The way your quote describes it implies a blazing blinding light warms everything, which is clearly not the case. There is mainly heat and some light.

    I presume halogen heaters are generally more efficient than oil radiators though but again, we're talking about one specific point in the chain. If you consider the electricity being generated by the power plant too then the oil radiator probably works out as more efficient.

    In the case of the halogen heater, of course you could say you want the light too...but then you can say that about anything. You could say a fanless PC is (nearly) 100% efficient if it's cold and you like the heat being emitted, etc.
This discussion has been closed.
Meet your Ambassadors

Categories

  • All Categories
  • 342.5K Banking & Borrowing
  • 249.9K Reduce Debt & Boost Income
  • 449.4K Spending & Discounts
  • 234.6K Work, Benefits & Business
  • 607.1K Mortgages, Homes & Bills
  • 172.8K Life & Family
  • 247.4K Travel & Transport
  • 1.5M Hobbies & Leisure
  • 15.8K Discuss & Feedback
  • 15.1K Coronavirus Support Boards