The TRNSYS Simulation Studio serves as a robust, intuitive, graphical front end of the simulation, making the user's job of assembling a detailed system a simple endeavor - similar in nature to hooking up the pipes and wires in a real system. The outputs of one component are graphically connected to the inputs of another. Since its inception of in the mid 1990's, the Simulation Studio has replaced the need to manually edit the text input file.

Users can watch the value of ANY system variable on an online plot as the simulation progresses (any temperature, flow rate, heat transfer etc.). Output devices also allow the user great flexibility in integrating, printing, and reporting any component output value.

Suite of Tools


With the release of version 17, TRNSYS included TRNSYS3D - a plugin for Google SketchUp™ that allows the user to draw multizone buildings and import the geometry (including building self-shading and internal view factors for radiation exchange) directly from the powerful SketchUp interface into the TRNSYS Building environment (TRNBuild).


TRNBuild is an interface for creating and editing all of the non-geometry information required by the TRNSYS Building Model. TRNBuild allows the user extensive flexibility in editing wall and layer material properties, creating ventilation and infiltration profiles, adding gains, defining radiant ceilings and floors, and positioning occupants for comfort calculations.


Historically, the text-based TRNSYS input file was generated manually. The addition of the Simulation Studio in the mid-1990s greatly reduced the need for manual editing. However, the TRNSYS environment still includes TRNEdit, a full-featured text editor for writing and viewing TRNSYS input and output files and for running parametric TRNSYS simulations. TRNEdit also serves as the editor for manually generating stand-alone distributable TRNSYS simulations called TRNSED applications.


TRNSED allows users to develop customized graphical interfaces for specific applications and then distribute those applications to non-TRNSYS users. These "web-page like" TRNSED applications allow non-TRNSYS users to change system parameters, run simulations, and process output without having to learn the intricacies of the entire TRNSYS Environment. To obtain some of the TRNSYS-based TRNSED applications that TESS has developed, please visit the TESS Projects website.


TRNSYS Standard Components

The standard TRNSYS library included with the purchase of the program includes many of the components commonly found in building energy systems. It also includes routines to handle weather data, solar radiation processing, basic HVAC equipment, hydrogen fuel cells, solar thermal and electric technologies, thermal storage, coupling to other simulation tools, and simulation result processing.

Download Standard Component Library Overview

TESS Libraries

The TESS Component Libraries contain over 250 components in 14 different Libraries.

TRNLIB Components

User written components that are donated to the TRNSYS community and which are publically available.

TRNAUS Components

These components are currently available for Australian TRNSYS15 users, but are currently being updated to be used with TRNSYS17.

Transsolar Non-Standard Components

The TRNSYS developer in Germany, Transsolar, has developed a number of the own non-standard components for TRNSYS users.

Programming Language

The TRNSYS engine, the standard component library and most of the publicly available non-standard component libraries are written in Fortran and are compiled into a dynamic link library for the Windows operating system. Users wishing to write their own components may write them in Fortran, C, C++, or any other language provided that they have a compiler capable of creating a DLL. Purchase of the TRNSYS Environment includes the source code for the entire kernel and all standard components save the multizone building model. Alternatively, components can be written in the TRNSYS "W" language in the TRNSYS Simulation Studio which does not require a compiler.

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