Detailed simulation of transient thermal effects in building enclosures

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BISTRA Features


  • Transient thermal simulation of all shapes in 2D
  • Geometrical input via BISCO format (steady-state variant)
  • Temperature dependent material properties
  • Detailed solar processor
  • Graphic animations (AVI files) of time varying temperatures
  • Software operational in English, French, German and Dutch


BISTRA Application fields

Application fields

  • Transient analysis of thermal bridges / construction elements
  • Glass fracture caused by solar radiation
  • Fire engineering (according to Eurocodes)
  • Floor heating (EN ISO 11855-2)
  • Ground heat losses (EN ISO 13370) and frost insulation (EN ISO 13793)
  • Phase change materials (PCM)
  • Dynamic thermal analysis of heating / cooling
  • Calculation of solar heat gains


BISTRA Input and geometric modelling

Input and geometric modelling

  • Same as in BISCO (also drawing and fill tools for bitmap editing)
  • Additional input of material densities and specific heat values
  • Thermal conductivities and specific heat values may be temperature dependent (e.g. useful in fire simulations)


BISTRA Dynamic boundary conditions

Dynamic boundary conditions

  • Boundary conditions are time dependent functions: constant, steps, periodic, reference climate, fire curve, user defined
  • Preview (with zoom) of time functions and temperature functions (material properties)
  • Improved simulation of (non-linear) radiation and convection by use of RADCON module



RADCON feature for BISTRA

  • Detailed simulation of radiation based on view factors

  • Extremely fast and stable calculation of non-linear radiation problems

  • Convection based on (calculated) convective heat transfer coefficient

  • Transparent materials for small cavities: conduction + radiation

  • Validated according to EN ISO 10077-2:2017 (radiosity method)




  • Graphic animations (AVI files) of time varying temperatures
  • Snapshots at any time step
  • Tables and graphs of time varying temperatures and heat flows



BISTRA Compatibility with other Physibel tools

Compatibility with other Physibel tools

  • BISTRA can read BISCO data
  • VOLTRA can read BISTRA data
  • Same function definitions as in CAPSOL


BISTRA Licence options

Licence options

  • BISTRA is available with perpetual licences or with subscription licences.
  • Subscription licences are protected with a software licence locked to a computer (stand-alone, network or cloud-based floating). With a subscription licence you get access to the latest version of BISTRA, technical support and Physibel Knowledge Base.
  • Perpetual licences are protected with a stand-alone licence locked to a hardware key. With a perpetual licence you get 1-year AMP (Annual Maintenance Plan). Renewal of AMP is not mandatory but continues your access to major version updates of BISTRA, technical support and Physibel Knowledge Base.  

what's new in version 4?

  • Possibility to simulate fixed sun position
  • Improved visualisation of sun path
  • Faster graphic output rendering
  • Software licence options (stand-alone/network floating/cloud-based floating)
Version history


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