[esp-r] Re: radiant and convective split for occupants

[Jian-lei Niu [BSE]]

Dear Jon,

I came to realize the limited data available sometime ago, when we wish to model the radiant distribution from students in a classroom. We had postulated that in case of stratified air distribution, this radiant distribution affects the actual space cooling load more than in the well mixed ventilation systems.

We tested with a direct radiation modeling method available in many CFD package, which was only roughly described in the paper. 

Xu H.T, Gao NP , and JL Niu, "A method to generate effective cooling load factors for stratified air distribution systems using floor level air supply", International Journal of HVACR Research,  vol. 15, no. 5, 915-930,  Sept. 2009 

But it seems to me that a simplified engineering calculation method for densely populated space is lacking. There are a few studies about the radiant heat from a single human body, including the famous Fanger model included in ASHRAE handbook, which  I guess is familiar to you, and some studies from Japan, by Prof. Tanabe, and Nakano etc.

I wiould like to hear more about this from this community as well.

Regards
Jianlei Niu

>>> Jon Hand <jon at esru.strath.ac.uk> 12/14/2010 5:22 PM >>>

I am updating some documentation about occupants in buildings related to
the radiant and convective split of sensible gains and I find that there are
a number of exemplar models that simply default to 50% radiant.  If I look
at the exemplar models that come with EnergyPlus I see most of them
are setting the radiant fraction of occupants to 30% and at least one
paper  mentioned 40%.

A Google search comes up with suggestions for what the sensible
is but mentions of how it is distributed seem to be well hidden.  In densely
populated spaces this must have an impact.

Does anyone have some or know about ...
 a) opinions that they would like to share
 b) some references that discuss this
 c) some papers that talk about it

Regards, Jon Hand
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