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.




    • CommentAuthorgravelld
    • CommentTimeSep 26th 2017
     
    I don't really trust PHPP to give me all the info I need for overheating design. It appears to only generate a whole building figure, which isn't much use if a south facing bedroom happens to be blazing hot during the summer and the north side cooler.

    Also the tolerance of 10% frequency > 25C seems a little too permissive for me!

    How have others handled overheating at the design stage, i.e. analysing how much of a problem overheating may be?
    • CommentAuthortony
    • CommentTimeSep 26th 2017
     
    Building physics model will tell you everything

    Alternative is external shutters and good insulation.
  1.  
    If a south facing bedroom is blazing hot then the the design is poor. As Tony says you can always use external shutters.
    • CommentAuthorgravelld
    • CommentTimeSep 27th 2017 edited
     
    Posted By: PeterStarckIf a south facing bedroom is blazing hot then the the design is poor. As Tony says you can always use external shutters.
    Well yes. What I'm asking is, what tools do you use to decide what the design should be?

    Shutters are a solution, not the design. I want to know why the shutters might work, and whether they are needed, and for which rooms.
    • CommentAuthortony
    • CommentTimeSep 27th 2017 edited
     
    Building physics model 3D house in computer simulation with real weather and sun data and expected occupancy.

    Will tell you overheating days and temperatures

    Smaller windows help a lot as does good insulation

    West facing windows are worse as sun comes in low late in day

    Big overhanging eaves or brise soleil should help you quite a bit
    • CommentAuthorgravelld
    • CommentTimeSep 27th 2017
     
    Any software recommendations?
    • CommentAuthorgyrogear
    • CommentTimeSep 27th 2017
     
    Posted By: gravelldAny software recommendations?


    yes, here's one...

    https://www.youtube.com/watch?v=lzGaLw__kdk

    gg
    •  
      CommentAuthordjh
    • CommentTimeSep 27th 2017
     
    Posted By: gravelldHow have others handled overheating at the design stage, i.e. analysing how much of a problem overheating may be?

    (1) don't rely on the limit in PHPP. Aim for a much lower %.

    (2) see http://www.peterwarm.co.uk/10-most-common-phpp-mistakes/ #9

    (3) see http://elrondburrell.com/blog/passivhaus-overheating-design/

    But having said that, 25°C is a very comfortable temperature.
    • CommentAuthorgravelld
    • CommentTimeSep 27th 2017
     
    I can't tell you how often I've read that 10 most common... WARM article and I still forgot about it. Will try a "stress test" tonight, thanks. Still worried about individual room overheating.

    25C is too hot for (quality) sleeping imo, but maybe I'm conflating different things.
  2.  
    Bear in mind that there is an 'individual room' test section buried inside PHPP where you can stress test specific overheating risks in a kind of mini-model if you are concerned about overheating to a particular room. Never tried it but I understand it was included to avoid the issues you mention above.

    I'd also recommend downloading the WARM dashboard (Results Sheet) which allows you to see a summary of all the PHPP outputs on one tab.
    • CommentAuthorgravelld
    • CommentTimeSep 27th 2017
     
    Errr... is there? I'm on 9.6a. I can't see it mentioned in the manual, is it one of those supplementary calculators like for shading? Thanks for the WARM dashboard tip-off.
  3.  
    Ah, my bad. There is a 'critical room' section but its for testing the risk of an abnormally high heat load (i.e. underheating rather than overheating).

    Opposite of your problem, I'm afraid...sorry for the red herring.
    • CommentAuthorgravelld
    • CommentTimeSep 28th 2017
     
    No worries, thanks.
Add your comments

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

© Green Building Press