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 or Post 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.
Last seen: Sep 15, 2026
@tskiado TRNOpt is an interface that facilitates setting up optimizations run by GenOpt (a generic optimization tool written by Lawrence Berkeley Na...
@juliatig This forum is intended to be a place where users can help users. You are welcome to post questions here. If you need support beyond what t...
@antonio sorry for not replying sooner on this. My guess is that either TRNSYS was installed in the .\Program Files\ directory (it should not be) o...
@amir_i The idea of Type780 is that you pass a moisture gain rate to the building model, which in turn deals with the latent energy impacts of addin...
@amir_i What timestep are you using for your simulation? It should be on the order of 1-5 minutes. Lately I have been using 0.02 or 0.05 hours as my...
@amir_i good question! Add a humidity gain in TRNBuild and assign it to be an input. You'll then connect the evapotranspiration mass flow rate to th...
@kashif10 can you also please screenshot the list of all the notices that are displayed along with the error? I am not so interested in the error or...
@hamza Sorry for the late reply. Type56 performs an energy balance on the roof surface and calculates a surface temperature. The energy balance assu...
@sw17032 It sounds like you are doing all the right things. It is hard to diagnose these problems because they are specific to the setup of each com...
@sw17032 I would recommend sending the project file and supporting files to your distributor's hotline so that they can look at the project in more de...
@sw17032 There are a few things that might be worth checking. first, are the source inlet and outlet temperature exactly the same value or are they ...
@am_hassan I will preface the following by saying that I am not an expert in this subject at all! However, there are a number of cases in which TRNS...