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.
Hello,
I would like to evaluate the temperature within the boundary layer just above the roof of a building.
To do this, I added a glazed veranda in TRNBuild, using a glazing defined in the "window" library with the following characteristics:
-
Marked as open window,
-
A very high transmission coefficient,
-
Allowing all solar radiation to pass through.
The goal is to analyze the influence of the roof surface temperature on the air just above it.
I also divided the veranda into several horizontal virtual surfaces to represent the thermal boundary layer, assuming that beyond this layer, the temperature equals the ambient temperature from the weather file.
However, the results obtained are not consistent. Could you advise me if there is another, more suitable method to model this problem?
Kind regards,
Hamza
Sorry for the late reply. Type56 performs an energy balance on the roof surface and calculates a surface temperature. The energy balance assumes that the ambient air in the vicinity of the roof is well mixed and it applies (user defined) convection and radiation coefficients in its energy balance. Inherent in the formulation of the energy balance is the assumption that there is not a microclimate just above the roof surface. Obviously in reality there is such a microclimate but because of the way that Type56's outside surface energy balance is formulated, its impacts are ignored. If you want to investigate the nature of the microclimate near the roof surface then you would need to write a new model (Type) for TRNSYS that creates an alternate outside surface energy balance. The new Type would still interface with Type56 in that you'd define the roof as a BOUNDARY rather than as an EXTERNAL surface. Type56 would pass the QCOMO (one of it's surface outputs) to your surface energy balance model and would receive in return the temperature that your energy balance computes as the surface temperature.
kind regards,
David
