[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [TRNSYS-users] time calculation

Matthieu,
Your explanation of what you are trying to do is very clear - thanks. I think that in order to speed up your simulation, you are going to have to write an iterative solution method in which you guess a solution and then check to see if it is a good one. If not, then you guess a different solution and try that one. Essentially the idea is the same as you have done in Excel but there are a lot of well known methods for writing such iteration methods. You might look for a book that is called "Numerical Recipes" (http://www.nr.com/) to get started. There are also some iterative methods implemented in certain TRNSYS Types; Types 543 and 544 in the TESS Solar Library contain one method for getting an iterative solution (implemented in Fortran). 
Cheers,
 David

At 10:58 9/6/2006, Matthieu Cosnier wrote:

Hello to all TRNSYS users,
I ve created a model of a "kind" of counterflow heat exchanger. It is composed of several subunits that represents small successive parts of italong the flow. This subunits are linked each others by the fact that the temperature of the outlet of one 
is the inlet temperature of the following one etc..
I know the temperature at the inlet of on side (hot fluid)and the temperature at the inlet of the other side (cold fluid). Each subunit is defined by a matrix system that calculate the outlet temperatures (on the cold side and on the hot side), knowing the inlet temperature of each. My problem is that i can't solve it easily because the only temperature i know are opposite (Tinlet hot and Tinlet cold) So i created an excel file that calculate all this equations with the option "solveur". The procedure is a step by step one, and consist of impose arbitrary values of each temperatures, to solve each system, to compare the calculated values to the imposed ones, and to start again if not. 
It works very good but it's quite slow (about 5 seconds).
The problem is that i have linked this program with Trnsys
(type 62), but as you can imagine it's very long to complete my simulation because each timestep is about 5 second long. My questions are : have i some solutions to do my simulation faster? may i use a fortran program (or another one)? and if yes, how to write it? ( i've never use fortran) 

Apologize for this bad english long text
Best regards
Matthieu.

°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°
COSNIER Matthieu
Doctorant
LOCIE
ESIGEC-Université de Savoie, Campus Scientifique,
Savoie Technolac, 73376
Le Bourget-Du-Lac cedex
Tel :   06 77 75 09 31
Fax :  04 79 75 81 44
E-mail : matthieu.cosnier@etu.univ-savoie.fr
°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°


_______________________________________________
TRNSYS-users mailing list
TRNSYS-users@engr.wisc.edu
https://www.cae.wisc.edu/mailman/listinfo/trnsys-users


****************************************************************************************
Thermal Energy System Specialists (TESS), LLC
David BRADLEY                           2916 Marketplace Drive - Suite 104
Partner                                        Madison, WI 53719
Phone: (608) 274-2577 USA
Fax: (608) 278-1475
E-mail: bradley@tess-inc.com
Web Pages:  http://www.tess-inc.com     and      http://www.trnsys.com

"Providing software solutions for today's energy engineering projects"
****************************************************************************************