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Soufiane_ZE Topic starter
24/02/2025 11:29 am
Dear TRNSYS Support Team,
I am encountering an issue during my simulation, and I received the following error message:
"TRNSYS Message 450: The maximum number of warnings allowed per simulation has been exceeded. Please fix these warnings or increase the limit on the number of warnings allowed per simulation (LIMITS command)."
Could you please advise on how to identify and resolve the warnings causing this issue? Additionally, how can I increase the warning limit using the LIMITS command if necessary?
Thank you for your assistance.
Best regards,
It is not really possible to diagnose the cause of the problem from the screen captures. However, if I had to make a guess based on the non convergent timestep and then the psychrometrics routine getting called with an unrealistically cold temperature I would first take a look at the simulation timestep and the capacity of the heat pump. Your thermostat models can only make one control decision per time step so if you have a small load, a long timestep and a heat pump with a large heating/cooling capacity then temperatures can really out of hand and cause the kind of error that you are getting. Your time step should probably be no more than 5 minutes.
As a side note, I think the heat pump model you are using is a constant speed compressor device that has one indoor unit and one outdoor unit. VRF heat pumps are a lot more complicated devices in that they typically have a single outdoor unit that contains a variable speed compressor (allowing the unit to adjust the amount of heating/cooling that it is delivering) and multiple indoor units. The standard TRNSYS library does not contain such a model but there is one available as an individual TESS component. As with a lot of VRF models the TESS component can only operate in heating or cooling mode at a given time. It is not able to operate in a mixed mode in which some of the indoor units are heating while others are cooling (which I realize is basically the whole point of VRF systems).
kind regards,
david
Dear David,
I truly appreciate your assistance.
If we were to create a VRF system, could you kindly advise us on the exact types we should use?
Additionally, I have another suggestion regarding a VAV system. I noticed that Types 151 and 152 are available. Could you please guide us on how to properly connect and configure them to establish a fully functional VAV system? Is there anything specific we should consider to ensure it operates correctly?
Thank you very much for your time and support.
Best regards,
DavidBradley 25/02/2025 4:59 pm
@soufiane_ze I don't think it is possible to model a VRF system with the components that are available in the standard library. You will need to get a Type (either by finding one available for free, by purchasing one that is commercially available, or by writing one yourself) that models the behavior of the VRF system.
kind regards,
David
DavidBradley 25/02/2025 5:00 pm
@soufiane_ze if you would like some more information about the commercially available TESS component that I mentioned in an earlier post, you can contact techsupport@tess-inc.com directly.
Soufiane_ZE Topic starter
26/02/2025 10:15 am
Can you provide me with websites where I can find a system like the one I need, please?
Dear TRNSYS Support Team,
I am encountering an issue during my simulation, and I received the following error message:
"TRNSYS Message 450: The maximum number of warnings allowed per simulation has been exceeded. Please fix these warnings or increase the limit on the number of warnings allowed per simulation (LIMITS command)."
Could you please advise on how to identify and resolve the warnings causing this issue? Additionally, how can I increase the warning limit using the LIMITS command if necessary?
Thank you for your assistance.
Best regards,
@soufiane_ze warnings are designed to alert you to a potential problem in your simulation. If there are only a few then they can generally be ignored. If there are a lot then they need to be addressed. Without looking at your simulation's *.lst and *.log files it is not possible to know exactly what is causing the warnings. For specific help on such issues you should contact your distributor. If you aren't sure who to contact, you can send an email to techsupport@tess-inc.com. They will ask you for some information about your license and get you pointed to the appropriate distributor hotline.
My guess as to the cause of the warnings is convergence; the components of your system cannot come to agreement and find a stable solution. Very often convergence problems are caused by using too large a timestep and/or heating and cooling equipment that has too much capacity for the load. Your timestep should not be more than about 1-5 minutes.
kind regards,
David
Thank you for your assistance..
Please, I would like to create a VRF air conditioning system. Do you have a pre-configured system that I can use and modify? I would greatly appreciate it. Is it possible, please, or not?
My E-mail : ze.soufiane19@gmail.com
I am not aware of any freely available components. The TESS component is available at https://www.trnsys.com
