[TRNSYS-users] Hconv and convective heat transfer coefficient

[Wirich FREPPEL]

Dear Adnan,

Though your paper is interesting and innovative, it does not answer to 
my questions. Indeed my problem is more about the process within TRNSYS 
than establishing the CHTC.

Again my concern is about the use of the CHTC. It seems that TRNSYS 
calculates another CHTC in order to get a HCONV. I would like to know 
the relationship between both and also why Req is close to zero, while  
I set up a high CHTC.

Hopefully someone has the answer.

Wirich FREPPEL
Ingenieur Doctorant en Recherche & Developpement
Centre R&D de Noirot - Groupe Muller
8 rue Louis Ampere, 02030 Laon
+33 (0)3 23 27 31 99

Le 01/03/2018 à 03:33, adnan rasheed via TRNSYS-users a écrit :
> Dear Wirich FREPPEL,
>
> Recently i did some work related to  internal and external convective 
> heat transfer coefficient and its effect on temperature  and Overall 
> heat transfer coefficient you can read the model calibration section 
> of the following paper "Development of a model to calculate the 
> overall heat transfer coefficient of greenhouse covers" . Hope this 
> will help you.if you have any question you are most welcome.
>
> here is the link of the paper
> http://revistas.inia.es/index.php/sjar/article/view/10777/3790
>
>
> Adnan Rasheed
>
> On Wed, Feb 28, 2018 at 11:21 PM, Wirich FREPPEL via TRNSYS-users 
> <trnsys-users at lists.onebuilding.org 
> <mailto:trnsys-users at lists.onebuilding.org>> wrote:
>
>     Hi everyone,
>
>     I ran 3 different simulations with TRNSYS, in which the only
>     parameter I changed was the convective heat transfer coefficient
>     CHTC (as seen in picture 1). It seems that nothing really differ
>     from a simulation to another, though I tried with h=1, then h=100
>     (see picture 6 which shows the airnode temperature). Then, in
>     order to identify the problem, I set as output the HCONV (type
>     108) and the resistance between the surface and the starnode Req
>     (type 86).
>
>     Two observations :
>
>     1) HCONV does not correspond to the CHTC I set in TRNBUILD (even
>     by dividing it by the surface area)
>
>     2) Req is very close to 0. I guess that's why I observe no real
>     difference between each simulation.
>
>     So I've got a few questions:
>
>     1) What am I actually observing with HCONV?
>
>     2) Why is Req close to 0 ?  And what does it mean? (I assume that
>     when Req=0, there is no heat transfer by convection between the
>     surface and the airnode)
>
>     Thanks in advance for the clarification
>
>     -- 
>     Wirich FREPPEL
>     Ingenieur Doctorant en Recherche & Developpement
>     Centre R&D de Noirot - Groupe Muller
>     8 rue Louis Ampere, 02030 Laon
>     +33 (0)3 23 27 31 99
>
>
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