Re: Passive Cooling System

["Philippe André" <andre@xxxxxxxxx>]

Dear Javier,

I would calculate (at each time step as it can be defined as an input) a
ficititious convective heat transfer coefficient which account both for
convection and radiation:

qcomb = qcso + qev
qcso = hcso* (tso-tamb)
qev = kcso * (pso-pamb)

where

pso and pamb are the saturation pressures
kcso is the evaporation heat transfer coefficient

We can globalize as:

qcomb = hcso,fictitious * (tso-tamb)

where hcso,fictitious = hcso+kcso*(pso-pamb)/(tso-tamb)

What do you think?


Philippe.

Philippe ANDRE
Fondation Universitaire Luxembourgeoise
Avenue de Longwy, 185
B-6700 ARLON
Belgique
Tel: 32 (0) 63/ 23 08 58
Fax: 32 (0)63 23 08 00
Email: andre@ful.ac.be
WEB: http://www.ful.ac.be
----- Original Message -----
From: Javier A. López U. <ja.lopez@cantv.net>
To: <trnsys@relay.doit.wisc.edu>
Sent: Thursday, June 21, 2001 1:52 PM
Subject: Passive Cooling System


>     Mr. David Bradley
>
>     First i'd like to thank you for taking some of your time to answer my
> question on TRNSYS use.
>
>     Attached to this e-mail i'm sending you a brief  diagram of the roof
> zone i'm trying to simulate on TRNSYS. This a passive cooling system that
> uses evaporative heat on the exterior surface of the roof as a product of
> the saturation presures difference between the air and water. I consider
> that adding the evaporative heat as "another gain" in the prebid interfase
> wouldn't be completly right, considering that this heat is not a zone
gain.
>
>     In the attached diagram the interior and exterior surface temperatures
> are not included and so are not the coduction heat on the roof, but they
are
> taken into account when simulating. So are other details, excluded for
> easier understanding of the diagram.
>
>     Thanks in advance for all your help
>
>              Javier Lopez
>
>     If any other on this list  beside you know anything that can be
helpful
> to solve my problem, i'd be glad if I could get a reply to this e-mail
from
> you.
>
> PS: I'm a  TRNSYS 14.2 version user
>
>