Tebodin is an independent engineering company offering their expertise and ser-vices  in a variety of different technical disciplines. One of their largest markets are turn-key  projects in refrigeration, heating and air conditioning of buildings. Depending on the  type of the building a wide spectrum of customer requirements have to be fulfilled, in  particular in modern muiltipurpose arenas for sports and other events, like concerts  and exhibitions. To optimize the air-conditioning with respect to all comfort, safety and  additional specifications for the different applications of the building, detailed  information of the air flow around and inside the building has to be known in an early  stage of the predesign. The required velocity data of the entire flow field can be  obtained by small scale wind tunnel tests or by flow simulations.  In the presented project the air-conditioning  of an ice hockey arena has to be designed.  One of the major additional requirements for ice hockey arenas is the  minimization of fog forming probability. Therefore FlowMotion has been asked  to determine the local fog forming probability for different concepts of the air  conditioning system. Since fog forming depends on much more than just the  velocity field, the required local velocity, temperature, pressure and humidity  have been determined by flow simulations (CFD Computational Fluid  Dynamics). With the help of this large data set areas of high fog forming  probability could be detected.  In this project the performed flow  simulations have proven their benefit  as an efficient design tool in many  ways. In the first place all relevant  flow magnitudes at any position  within the arena could have been  determined less time and cost con-  suming as compared to an expe-  rimental approach. In the second  place the influence of variations in  the position, dimension and setup of the air conditioning system on the fog forming could be studied more  scientifically. This could be achieved by varying the different parameters separately, which cannot always be  guaranteed in experiments.   This project shows that a higher degree of optimization and efficieny can be achieved by numerical studies for building  ventilation, which finally leads to a reduction in investment and running costs for the air conditioning system.   Offices: The Netherlands Leeghwaterstraat 21 2628 CA Delft Tel.: +31 15 278 2907 Germany Weenermoorer Str. 193 26826 Weener Tel.: +49 4953 922 969 Consultancy for Heat Transfer and Fluid Dynamics CFD makes fluid dynamics visible. ANSYS We solve every Flow problem. Misty Hockey Design of a ventilation system for a multi-purpose sports arena TEBODIN www.tebodin.nl fog temperature velocity in the  plenum windtunnel-test