[TRNSYS-users] a problem with the pipe (type31) algorithm

Jeff Thornton thornton at tess-inc.com
Mon Jun 29 21:57:55 PDT 2020


Pengfei Han, 

Are you sure you have everything hooked up correctly and are watching
the pipe output temperature and not the average temperature? When I
perform the indicated test in TRNSYS 18 I get exactly as I expect - see
attached image. 


Jeff Thornton
President - TESS LLC
3 N. Pinckney Street, Suite 202, Madison WI USA 53703
Office: (608) 274-2577 Fax: (608) 278-1475
E-Mail: thornton at tess-inc.com

On 06/29/2020 3:29 am, han_pf via TRNSYS-users wrote: 

> Dear experts, 
> I think there is a problem with the pipe (type31) algorithm. 
> Due to the length of the pipe, changes in the input temperature do not immediately affect the outlet temperature. This phenomenon is very noticeable with long pipes. However, in trnsys, the outlet temperature of the pipe changes immediately regardless of the length of the pipe setting. As shown in the figure below, in a 1km pipe, when the input temperature changes by a step, the outlet temperature changes immediately. Is there a solution to this problem? 
> Thanks & Best Regards! 
> Pengfei Han Ph.D. Student 
> 1-235, School of Electronic Information and Electrical Engineering, 
> Shanghai Jiao Tong University Minhang Campus 
> 800 Dongchuan Road, Minhang District 
> Shanghai, P.R.C. 
> Post Code: 200240 
> Mail: han_pf at sjtu.edu.cn 
> _______________________________________________
> TRNSYS-users mailing list
> TRNSYS-users at lists.onebuilding.org
> http://lists.onebuilding.org/listinfo.cgi/trnsys-users-onebuilding.org [1]

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