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

Categories



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.

Buy individually or both books together. Delivery is free!


widget @ surfing-waves.com




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.




    • CommentAuthordelprado
    • CommentTimeJan 31st 2018
     
    The megaflows must have a huge share of the market, given how much cheaper the alternatives are.

    Has anyone used them and can comment?

    Joules
    Gledhill
    Etc?
    • CommentAuthorgravelld
    • CommentTimeJan 31st 2018
     
    Or totally different: Sunamp.
    • CommentAuthordelprado
    • CommentTimeFeb 1st 2018
     
    Having read their website I cannot for the life of me fathom what is is gravel!
    • CommentAuthorborpin
    • CommentTimeFeb 1st 2018
     
  1.  
    ''Having read their website I cannot for the life of me fathom what is is gravel!''

    Gravel? Had a quick scan of Sunamp site/residential and can find no ref.
    • CommentAuthorgravelld
    • CommentTimeFeb 1st 2018
     
    Gravel - useful for backfilling!

    delprado - it's a store of energy which uses a phase change material (salt I think) rather than water (as conventional cylinders do) to store the energy. The advantage is a far higher energy density which also means a far smaller unit which in turn means much lower heat loss - both because of the size and also the fact that very effective insulation is used (vacuum panels iirc).

    Check out BuildHub, there are a few people who have installed them.

    I'm sure you'll pay an early adopter fee though!
    • CommentAuthorgoodevans
    • CommentTimeFeb 1st 2018
     
    I'm also interested - I'm trying to avoid a combi boiler - the Gledhill units seem to be good value and comprehensive but I'm put off a little because the heat loss seems high (45 watts plus - but at least they publish unlike others) also because of the external heat exchanger there are electrics and pumps that can go wrong. But on the other hand the tank is a simple as can be and all the bits can be repaired/replaced.

    All I want is a simple store with a finned/substantial coil for DHW (or two coils), an immersion heater (for if/when I have solar PV and boiler failure) and, ports for the boiler and heating.

    I'm avoiding combi boilers because they seem overly complex and don't seem to fit with UFH.
    •  
      CommentAuthordjh
    • CommentTimeFeb 1st 2018
     
    Posted By: goodevansI'm avoiding combi boilers because they seem overly complex and don't seem to fit with UFH.

    I'm curious why they don't suit UFH?
    • CommentAuthorgoodevans
    • CommentTimeFeb 2nd 2018
     
    I have to admit it's a bit of a prejudice I have - possibly unwarranted - I wish to run my UFH near continuously at a relatively low temperature to keep the house temperature stable - but I suspect a combi will not modulate down to say 1 or 2 kw so it will have to regularly fire up for a few minutes at a time - (although little heat will be wasted here as the boiler is within the building envelope).

    It just feels wrong to size a combi for the peak energy flow you need occasionally and yet run it at the bottom end of its range. I prefer the idea of running a smaller, simple system boiler, having storage for several minutes of shower use and letting the boiler catch up over the next 20 mins or so.

    However I suspect that the combi boilers loose less than 45w on average so perhaps this is the way to go. I'll just have to get used to the combi firing up every few minutes when the weather is cold.
    •  
      CommentAuthordjh
    • CommentTimeFeb 2nd 2018
     
    Ah, OK, that makes sense to me. Thanks.
    • CommentAuthorTimSmall
    • CommentTimeFeb 2nd 2018 edited
     
    Posted By: goodevansI suspect a combi will not modulate down to say 1 or 2 kw so it will have to regularly fire up for a few minutes at a time
    [...]
    I suspect that the combi boilers loose less than 45w on average so perhaps this is the way to go. I'll just have to get used to the combi firing up every few minutes when the weather is cold.


    I have a 10 year old 24 kW Vaillant combi (because that's what was in the house before I took it apart and put it back together again), it will modulate down to 6 kW (where it runs at it's max efficiency of "98%" or so).

    Because my UFH zones have quite high thermal mass (all in concrete or high-conductivity screed), the boiler will fire for about an hour when all the zones are on and the heating hasn't been on for a few hours (it's set to cut off at a flow temperature of 44 C - which is the lowest temperature the settings allow).

    I think Viessmann do a high efficiency combi about the same size which will modulate down to 1 or 2 kW.

    A sub-£1000 air source heat pump, with a heat output of about 3 kW would be nice...
    • CommentAuthorgoodevans
    • CommentTimeFeb 2nd 2018 edited
     
    This link kind of supports my thoughts - it's marginal but I think for me a store just wins out.

    https://energy-surprises.blogspot.co.uk/2012/10/combi-boiler-versus-hot-water-tank.html

    But back to delprado's original post - why would you not go for say a Gledhill for price.
    • CommentAuthorborpin
    • CommentTimeFeb 2nd 2018
     
    The other thing is to heavily insulate the pipes close to the tank. I have double insulated so there is about 60mm wall thickness of insulation.
Add your comments

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

© Green Building Press