Dynamic simulations

Nowadays the increased use of prediction instruments in buildings is required. Kopitsis Bauphysik AG has been specialised is such computer-based modelling techniques since 1986 and offers customised thermal building simulations and air flow simulations.

Thermal building simulations

As part of thermal building simulations, the concepts of room conditioning and the façade are investigated in detail for selected building areas in respect of their interaction with the expected use. To put it another way, the building is placed on a virtual test bed by means of a computer calculation. The result is predictions about the thermal behaviour throughout the annual cycle at short time intervals based upon which practical building recommendations are made for further planning.

The simulations are performed with the programs HTB2 and EnergyPlus/DesignBuilder. The process includes the following steps:

  • Creation of the simulation model (multi-zone model) using 3D-modelling
  • Use of hourly weather data by location and load profiles dependent on the building type and use
  • Detailed design of HVAC systems
  • Use of different HVAC systems (floor heating, air coolers, combination, etc.)
  • Use of natural and/or mechanical ventilation
  • Use of various sun and glare shield systems with solar control
  • Prediction of natural daylight distribution in rooms using radiance simulations

The simulation results are evaluated based on the following viewpoints:

  • Calculation of the energy consumption of buildings
  • Determination of the expected indoor air, surface and operating temperatures
  • Comfort evaluation based on PMV index (predicted mean value) and PPD Index (predicted percentage of dissatisfied)
  • Determination of relative air humidities
  • Determination of simulation outputs of the HVAC systems (flow, return temperatures, volume flow, etc.)
  • Calculation of losses/gains due to internal loads, windows, HVAC systems, etc.

Air flow simulations

Air flow models based on computational fluid dynamics (CFD) can predict the air flows and the resulting heat distribution inside the building.

They can likewise also be used to predict the natural ventilation rate and the movement of pollutants or smoke distribution in rooms containing a fire (smoke simulations).

Essential aspects of the investigation using air flow simulations are air and surface temperatures, heat flux densities due to components, mass flow rates, etc.

The air flow simulations are performed using the programs WinAir and EnergyPlus/DesignBuilder and the smoke simulations using the program Fire Dynamics Simulator (FDS).