Welcome to the TRNSYS Users Forum.
The forum is a place where people can interact and have discussions about different topics involving the use of the TRNSYS software package. Here you can post topics for discussion or questions on using TRNSYS and get advice from other users or TRNSYS experts. This forum is not intended for detailed technical support. Users should contact their distributor’s hotline for such assistance.
Some tips for success on using the forum:
- Follow the Forum Rules posted in Forum Administration.
- There are categories for different types of topics and questions. Post your topic or question into the proper category.
- Before posting a topic or question search the existing topics (and the TRNSYS Users listserv archive) to see if a similar topic or question has already been answered.
- Use a descriptive topic name. Don’t use attention getting subjects, they don’t get attention and only annoy people.
- State the version of TRNSYS and which add-ons your are using.
- Include enough specific details for your topic of question to be answered. Just posting “Why am I getting an error?” without describing the specific error and what you are trying to do when you get the error will not receive a response that fixes your issue.
- Remember when people help you, they are doing you a favor. Be patient, help people out by posting good descriptions of what you need help with, and be polite even if a response does not solve your issue.
- Moderators may edit your post for clarity or move your topic to a more appropriate category.
I am trying to simulate the initial heating process of a cold room with an underfloor heating using an active layer.
My problem is that TALM "node temperature of active layer" always starts at 20 °C.
The "Initial zone temp." in Zone -> Initial Values is set to 12°C. The connected ground temperature is also set to constant 12 °C. I am using weather data connected to the other Building inputs like TAMB, TSKY, ....
At the start of the simulation this results in a postive heat transfer QCOMI "energy from inside surf. incl. conv. to air and longwave
radiation to other surfaces" although the underfloor heating is "off" (no inlet mass flow).
In this example TSI starts at 16 °C (mean value between TALM and TAIR).
Other example:
TGround and "Initial zone temp." set to 8 °C -> Result: TALM starts at 20 °C, TSI starts at 14 °C
What I would suggest is that you run your simulation for a day (simulation time, not real time!!) with a constant 12C (or whatever is appropriate) flowrate going through your active layer. That will precondition the system to get rid of built-in initial values. You can set up your integrators and printers to start a day late or your can start your simulation on 8736 and run it through 17520 but start your integrators and printers at 8760.
kind regards,
David
