Re: [TRNSYS-users] Air-coupling vs TRNFLOW

["David Bradley" <bradley@tess-inc.com>]

Dear Arnaud,
  The most correct way of assessing the air coupling between the two zones
is to use TRNFlow or CONTAM/Type97. If you don't, you'll have the
conductive heat transfer between the two zones (through the virtual
window). If you use TRNFlow or CONTAM, you'll add the convective
portion, which is likely more substantial. Since TRNFlow and Type97
require rather extensive work to implement, you could also look at the
ASHRAE97 Fundamentals handbook and extract the equation that gives
two-way flow through an opening as a function of the temperature
difference across the opening. You should be able to implement that as
an equation in your input file and it would at least give you an
approximation (slightly better than a guess) of the coupling flow.
Kind regards,
 David




----- Original Message -----
From: "" <a.thome-08@student.lboro.ac.uk>
Sent: Wed, July 29, 2009 4:12
Subject:[TRNSYS-users] Air-coupling vs TRNFLOW





Hello everyone,


I have used "virtual windows" to connect adjacent thermal zones together.

Now, I installed a powerful biomass stove (air flow=1000 kg/hr and heating
capacity of 20 000 kJ/hr) in the main room: living room. I would like to
asses the gain from this stove to the adjacent rooms which are connected to
the main room by these "virtual windows".

Does the use of "air coupling" is enough? if yes, how should I estimate the
air coupling between two zones. ( I made différent tests with different air
coupling and it has a big impact on the adjacent room temperature)

Or should I use TRNFLOW?

Thank you very much,

Best regards,

Arnaud
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----- End of original message -----