Home  5  Books  5  GBEzine  5  News  5  HelpDesk  5  Register  5  GreenBuilding.co.uk
Not signed in (Sign In)


Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

PLEASE NOTE: A download link for Volume 1 will be sent to you by email and Volume 2 will be sent to you by post as a book.

Buy individually or both books together. Delivery is free!

powered by Surfing Waves

Vanilla 1.0.3 is a product of Lussumo. More Information: Documentation, Community Support.

Welcome to new Forum Visitors
Join the forum now and benefit from discussions with thousands of other green building fans and discounts on Green Building Press publications: Apply now.

    • CommentAuthorJohn11668
    • CommentTimeApr 2nd 2007 edited
    I have a customer with a large wind generator, high in the pennines and whenever I visit it is whistling away.
    The control system "dumps " surplus power via a large heater element on the back wall. The oiler fired Rayburn 368K is not sufficient to heat the house and supplementary heating is needed. It occurs to me that a couple of good sized commercial immersion heaters in an accumulator tank could let the excess energy be utilised. The house heat losses will be high on a windy day when the machine will be producing too much power so feeding it back into the house seems logical
    Does anyone have experience of this type of installation or links to any useful sites?
    In theory you don't need any electrical apparatus: you can have a simple purely mechanical system with the windmill rotaing paddles to stir the water in a tank
    • CommentAuthorPeter A
    • CommentTimeApr 2nd 2007
    On the previous forum I read about a home that was off grid and using a 6kWh wind turbine, when it was producing to much energy they dumped it into night storage heaters, seemed a very simple solution which I have never heard an "expert" suggest, might be worth a go?
    • CommentAuthorGuest
    • CommentTimeApr 2nd 2007
    I went to a talk by a bloke call Paul Mobbs a while ago.
    He said that he had seen this being done by some of the more extreme survivalists in the US.
    Don't think you need the political beliefs to benefit!
    It might be worth getting in touch with him Paul.
    This is his web site.
    I think I'm the person with the storage heaters which Peter A mentioned.

    We have a Proven 6kW wind turbine. We've installed three storage heaters and one convector heater to use up surplus power, and are soon to add more to the system. There is a failsafe coil attached to the wall in the control shed, which rarely gets even warm.

    Some people use the immersion heater system, but that disperses the heat over the whole house and only results in a small increase in heat. Our system focusses the heat where it is most needed.

    If the original poster would like to have a chat about what we did here, email me on info at peafowl dot freeserve dot co dot uk, and I'll send over my phone number. Make sure you put something obvious in the subject line, though, as we get a lot of spam which we delete without hesitation!
    • CommentAuthorPeter A
    • CommentTimeApr 4th 2007
    Hi Jane, thanks for that gem of an idea, I've mentioned it to quite a few people now and they are genuinely amazed that such a simple idea has so much potential.
    • CommentAuthorGuest
    • CommentTimeApr 4th 2007
    We were amazed that no one else had really investigated it. Even Proven (who made the wind turbine) were not sure it would work, but it has, and very well.

    I'm assuming that John's client is off-grid... in which case, warn the client to ensure their control box is wired up correctly. We had three system fires, two of which were caused by Proven wiring things up wrongly... they tried to blame our storage heaters, but eventually managed to prove that they'd done it wrong to start with. They're not used to dealing with off-grid installations, and with our one, it showed.

    By the way: you can have up to five dumploads (we intend to add another) and as storage heaters don't keep drawing power once they're as hot as they can get, we're going to wire in further storage heaters for next winter which come on once the original ones get full up. Hope that makes sense. Ours is a very windy location, so I can't guarantee everyone else will need to do that, but it'll be worth it for us.

    We're also wiring our rainwater collection tank so that the water is only pumped from the tank when the dumpload is on... it won't make much of a difference, but it'll make us feel smug. Which is important.

    And we heard today that we've been shortlisted for the Yorkshire and Humber Microgeneration awards so either our storage heaters are considered a generally good thing by more than you and me, Peter, or there weren't many entrants. I'm hoping it was the former.
    Sorry, that was me--don't know why I was logged out that time.
    • CommentAuthorGuest
    • CommentTimeApr 4th 2007
    i suppose i should really start a new topic here - but we have just had a proven 6kw turbine put up - and we are wondering if there is anyone that is selling their surplus power at more than 4.5p per unit. seems v.unfair that to buy it would cost 11p per unit! obviously we are still connected to the grid.
    I think NPower might be the place to start, but am not sure as we're offgrid so don't have the option.
    • CommentAuthorJohn11668
    • CommentTimeApr 4th 2007
    Thanks for all your comments folks.

    I am not sure of the capacity of this rig but 6 Kwh would sound about right.
    It is indeed off grid so there is no buyback option. I bet the windfarms are getting more than 4.5p for one of their units so that rate does seem a bit unfair. Having said that I presume it can only be used locally without processing costs to step it up to distribution voltage.

    I am particularly interested in the using the output for water heating as there is a full wet system in the property, albeit that the boiler has insufficient capacity. I see it as a way of boosting the output of the system for little extra fuel cost.

    The house is a large tied farmhouse with a single occupant, his duties oblige him to live there but he does not use electricity for much more than lighting. His employer is prepared to fund the upgrading of the system but it seems mad not to utilise the surplus power. I could incorporate an electric boiler but this would mean using the heat immediately unless an accumulator tank was incorporated.
    • CommentAuthorPeter A
    • CommentTimeApr 4th 2007
    Jane, good luck with the award, the storage heaters alone are worth it.
    John if wall space isn't too much of an issue I'd leave the wet system well alone and let it complement the storage heaters.
    • CommentAuthorJohn11668
    • CommentTimeApr 4th 2007
    As a heating engineer I am opposed to the principle of storage heaters in that they cannot be adequately controlled .
    They heat up when power is available and give off the heat in at a progressively reducing rate as they cool.
    I recognise that we are talking about free energy here ,in that if it were not put into the storage heaters it would be wasted in the outside air, but we are hoping for a solution which permits us to release the heat at useful times, rather than when there is no-one at home to enjoy it.
    • CommentAuthorPeter A
    • CommentTimeApr 5th 2007
    John, I can understand where you are coming from it just sounds like an expensive option, if it is that rural why not a log burning stove that is linked to heating circuit?
    If you'd prefer to use the wet system then that's the most usual way to go. An immersion heater is installed in a piece of fat pipe (drainage pipe?) to replace part of the existing pipe run, usually just before the boiler. Add a thermostatically-controlled pump which switches on when the water around the immersion heater gets hot, and you're done. With the Proven you can have up to five dump-loads, and so five immersion heaters. If going this way I'd have preferred to have the immersion heaters fuelling a tank, rather than the fat pipe method, to give some storage, but the fat pipe way is the most usual. So I'm told.

    Can you let me know who installed the wind turbine? It seems odd that this hasn't been looked at. If this is a Proven 6kW, as ours is, then who ever installed it should have dealt with the dump-loads at installation, and it's ridiculous that they didn't. However, there should be relays in place in the top right-hand corner of the wind turbine control box which will control the dump-loads, but make sure these are wired in correctly--it was these that failed and caused one of our fires, as they were feeding power back to the other dump-loads and so overloading them. If they're not present, contact Proven about getting the control box altered--they should handle all that for you. If it would help to come and look at ours you're welcome.
    • CommentAuthorJohn11668
    • CommentTimeApr 9th 2007

    I value your experience but the fat pipe seems a bit crude when there are bits of kit on the market like the trianco Aztec.
    The fat pipe sounds like a way of sending all superfluous heat into the house, but wouldn't it be nice if it went there when it was useful, hence the idea of using an accumulator tank to keep the heat until the folks come home to enjoy it.

    It worries me that the people in the forefront of green technology are using pretty crude science.

    I cant see a woodburner being more environmentally friendly, particularly for a guy who is out on the hills most of the day and wants to come home to a comfortable house,
    Not necessarily cheaper either if you have to pay £8-1200 for a stove , at least that again for a suitable flue and heaven knows what figure for a Hetas Reg installer.

    The Guy already has more free electricity than he knows how to use, we are trying to use it in the most effective way.
    Regarding selling your power, from what I can make out, Good Energy offer 4.5p per unit to off-grid micro generators. The payments are based on estimated generation i.e. it is not metered:-

    • CommentAuthorJohn11668
    • CommentTimeApr 11th 2007
    Surely the fair way would be to meter the units flowing both ways and the householder pay for the actual (net ) consumption. But you would not really expect big business to play fair would you?
    • CommentAuthorGuest
    • CommentTimeApr 11th 2007
    So far the discussion has been around using surplus electrical energy to generate heat.
    Heat is a relatively low grade form of energy which is pretty much where it all ends up anyway (isn't it?)
    Would it be better to consider using surplus electrical energy to drive you fridge and or freezer?
    They are two considerable electrical loads which can have a considerable amount of freedom as to when the energy is applied (but we rarely take advantage of this).
    How about organising a separate insulated cold box, filled with water just above your fridge.
    In times of surplus electrical power, use it to freeze the water to ice. Organise a secondary circuit of some suitable fluid (no idea what) which circulates between the ice and the fridge. This fluid doesn't need to go through the normal compress, cool, expand, heat cycle of a fridge, it just needs to remain liquid at a temp. lower than you ever get your ice down to (salt water?). As long as it has normal bouyancy it will move heat from the fridge (at 5deg) up to the ice (at -5deg), or more importantly it will move coolth in the other direction.
    It needs lots of energy to turn ice at 0deg into water at 0deg, and all this will be drawn from your fridge, thus keeping it cool.
    No idea how you control the flow of heat from fridge to ice, maybe just a simple throttle on the circulating liquid.
    You could probably do something fancy with the heat you suck out of the ice, or maybe you could keep the ice outside the house insulation layer and have a longer secondary circulation system which passes through the house insulation layer.
    Electrical is too good to just to dump into water as heat.
    • CommentAuthorJohn11668
    • CommentTimeApr 12th 2007
    Except that the guy has used as much of the generated power as he can. He has fairly light usage . His fridge and freezer are fully supplied , otherwise he uses lights ,computer, telly but not much else. He rises early and is out most of the day. It is only evenings when he needs extra heat and on a windy night when he as more power than he needs he also needs more heat due to the wind chill effect on the property.

    If he were on the grid he could flog a few units back at 4.5p and buy fifty percent more oil units at 3p/Kw Hr but he isn't so he cant and it seems mad that his excess is just used to warm his back yard.

    It is a bit of extra warmth he needs, his fridge is doing an far better job already than you or I ever could ever do with a Heath Robinson cool box
    John, 5 months on from the last entry I presume that you'll have moved on but wondered if you looked into Phase Change Materials for the heat storage?

Add your comments

    Username Password
  • Format comments as
The Ecobuilding Buzz
Site Map    |   Home    |   View Cart    |   Pressroom   |   Business   |   Links   

© Green Building Press