[esp-r] Re: Air flow network simulation without building and plant

[Jon Hand]

Hello Clodoaldo,

The error is what we call a string buffer overflow - more characters are being written to
a string variable than it can hold.  The error is happening when it is trying to compose
a menu.  We would need to do some debugging while attempting to create the same
network to get past this.  To help us with this can you send a sketch of the network
you wanted to create along with the names of the entities that you tried to use so
the fault can be duplicated?

Until this can be done why not try an alternative approach?

It seems like a simple network.  Is there a reason you do not use a simple box model
of a thermal zone with it? This will us the much more common bps simulator to
solve both the zone and the flow network - so you get the dynamics.

There are a number of YouTube videos which show aspects of setting up flow
networks.  Look in the ESP-r tutorials and ESP-r demonstrations videos here:

https://www.youtube.com/@jon.in.glasgow1989/playlists

[https://yt3.googleusercontent.com/ytc/APkrFKaDWu9hOdnj4SOFPxN5bZCKLfnEzXE0K2mldgSt=s900-c-k-c0x00ffffff-no-rj]<https://www.youtube.com/@jon.in.glasgow1989/playlists>
jon.in.glasgow<https://www.youtube.com/@jon.in.glasgow1989/playlists>
www.youtube.com
There is also a chapter all about flow networks on the Strategies web page:

http://contrasting.onebuilding.org/Strategies/Index.html

Regards, Jon Hand
________________________________
From: esp-r-bounces at lists.strath.ac.uk <esp-r-bounces at lists.strath.ac.uk> on behalf of Clodoaldo Carvalho Filho <clodoaldo at ufc.br>
Sent: 01 October 2023 19:54
To: esp-r at lists.strath.ac.uk <esp-r at lists.strath.ac.uk>
Subject: [esp-r] Air flow network simulation without building and plant

Hi you all,

I need to configure and simulate a simple supply ventilation system. The system has a fan connected to the zone by a supply grill (local pressure loss), and the zone is connected to Exhaust by an exhaust grill (another local pressure loss).

I am trying to do it in ESP-r, but I am experiencing some difficulty configuring the air flow network (afn) in enet and simulating it without building and plant in mfs. The afn has 4 nodes, 3 components and 6 connections (config file attached).

enet crashes every time I try to change "i cross-sectional area (m^2)" in X11 interface and returns the following:

At line 221 of file netwedit.F
Fortran runtime error: End of record

Error termination. Backtrace:
#0  0x7fc546e23960 in ???
#1  0x7fc546e244d9 in ???
#2  0x7fc546e2510f in ???
#3  0x7fc547077360 in ???
#4  0x7fc54708422c in ???
#5  0x7fc54707ab84 in ???
#6  0x7fc54707ae05 in ???
#7  0x562913fcb789 in ???
#8  0x562913f7a360 in ???
#9  0x562913f5a7be in ???
#10  0x7fc546a29d8f in __libc_start_call_main
at ../sysdeps/nptl/libc_start_call_main.h:58
#11  0appreciatedx7fc546a29e3f in __libc_start_main_impl
at ../csu/libc-start.c:392
#12  0x562913f5a8a4 in ???
#13  0xffffffffffffffff in ???

I am not sure the afn configuration is consistent with what mfs needs to run ok. The pressures calculated at the internal nodes are zero and mass flows at connections have different values (one of them is zero) when it should be equal. Why?

Is there an example of a mass flow network without building and plant in ESP-r training directory?

I am using the Network tool of ESP-r V13.3.16 of 1 June 2023, built on

  Platform -         x86_64:Linux:6.2.0-33-generic
  Compilers -        gcc/g++/gfortran
  Graphics library - X11
  XML output -       Supported

Any clue to help me succeed in simulating this afn will be appreciated.

Best regards,

Clodoaldo.

Prof. Clodoaldo de O. Carvalho Filho, Dr.
Universidade Federal do Ceará
Depto. de Engenharia Mecânica
Lab. de Eficiência Energética no Conforto Ambiental - Coordenador
ASHRAE Fortaleza Student Branch - Advisor

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