[Bldg-sim] Fw: exterior convection coefficient for tilted roof

[leen peeters]

Hi Chris,

CIBSE suggest to replace g with gcos(theta) in the Grasshof number. That
means, it accounts for the roof being tilted in natural convection. When it
comes to roofs, there is another aspects that starts to be important ...
the roof finishing in tiles will have a 'detoriated' velocity underneath
the tiles. It is mainly that one directing the convective losses ...

Am I correct on this?

Leen


On Sat, Feb 11, 2012 at 11:45 PM, Chris Yates <chris.malcolm.yates at gmail.com
> wrote:

> It's true wind does dominate external convection.
>
> Cibse guide A will give you all the numbers that you're looking for
>
> Chris
>  On 11 Feb 2012 22:40, "Paul Hay" <phcjam at yahoo.com> wrote:
>
>>  I've only seen reference values of interior convection coefficients for
>> tilted surfaces, not exterior coefficients: which are available for summer
>> & winter conditions, due to the difference in wind velocity.
>>
>> Paul Hay MBA, BA(Arch)
>> Managing Partner
>> PAUL HAY Capital Projects
>>
>> Caribbean Capital Project Management & Planning
>>
>>
>>
>> P.O.Box 3367
>> Constant Springs, Kgn. 8
>> Jamaica, W.I.
>>
>> tel: 1 (876) 756-0631
>> cel: 1 (876) 324-4274
>> fax: 1 (876) 756-0631
>>
>> e-mail: paul.hay at phcjam.com
>> skype name: phcjam
>> twitter: http://www.twitter.com/phcjam
>> web: http://www.phcjam.com
>> profile: http://www.linkedin.com/company/paul-hay-capital-projects
>>
>>
>>
>>
>>  ----- Forwarded Message -----
>> *From:* leen peeters <l.f.r.peeters at gmail.com>
>> *To:* bldg-sim at lists.onebuilding.org
>> *Sent:* Saturday, February 11, 2012 2:59 PM
>> *Subject:* [Bldg-sim] exterior convection coefficient for tilted roof
>>
>>  Dear,
>>
>> can anyone point me to some reference values for exterior convection
>> coefficients for tilted surfaces like a roof?
>>
>> Thanks
>>
>> Leen
>>
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