Buildings with large enclosure often present unresolved problems related to energy and air flows such as unwanted thermal stratification, local overheating, uncontrolled contaminant spreading. These kind of constructions are often found in unique buildings where innovative designs are developed. Consequently, there exists no previous experience and very careful analysis on the ventilation design is advisable [1]. This is particularly true for the halls of the "Citt dello Sport" in Rome, designed by Santiago Calatrava, because of their singularity in term of dimension and shape.

Current control strategies for central air conditioning typically adopt a machine-centered, energyconsuming approach that focuses on creating constant, uniform neutrality-conditions whichmight actually be perceived by some occupants as thermal monotony or sensory deprivation.There are needs for more sophisticated and responsive environmental control strategies,enhanced levels of thermal comfort and acceptability among occupants.

The European standard prEN 13779 - Ventilation for non-residential buildings [1] distinguishes four categories of decreasing air quality, ETA 1 to 4, for rooms in buildings. We tested the separation effectiveness between a special designed smoking porch, which is a typical ETA 3 room, and the adjoining lobby at Delft University of Technology. The ventilation effectiveness in the smoking porch, which was heated and ventilated by a pseudodisplacement ventilation system, was measured as well.
For the ETS measurements we used an innovative Ultra Fine Particle sensor, newly developed

A typical virtual meeting room with occupants displays different situations of airflow pattern for different locations of the air supply even though the ventilation system has the same loca-tion of the air exhaust in the room. The pollutant is defined here as CO2 emitted by the occu-pants in the room. - The investigation is realised with full-scale numerical modelling under Computational Fluid Dynamics (CFD) method.

Since 2005, the Leiden University Medical Center started the building of the new departmentof children Intensive Care (IC). Several types of geometry have been planned in the department, In order to minimize the cost and get the most applicable result, an IC room with two beds in serial has been chosen for the detailed aerodynamic study. The CFD model of the IC room with two beds in serial is studied. The CFD model will split the whole room as many small mesh elements to fulfil the conservations of mass, momentum and energy.

The air distribution components in a variable air volume (VAV) flow system influences the overall function of the system. A low supply air temperature and a wide working range in terms of airflow rate, facilitate high energy efficiency. However, in order to achieve these properties, high demands must be set on the function of the supply-air diffusers.

In many climate zones, low energy buildings will not be able to utilize natural ventilation at all times. Hence, low-energy mechanical comfort systems will still be required. For green buildings there are design objectives well above minimum standards for comfort and indoor air quality (IAQ) that are meant to improve occupant productivity. The latter can make meeting low-energy requirements even more challenging. To meet these sometimesconflicting requirements, the principles of concurrent engineering may be applied to support design charettes.

The potential of improving perceived air quality indoors was quantified when low-polluting materials are used and when building ventilation is increased. This was done by studying the relationships between ventilation rate and the perceived indoor air quality. A sensory panel assessed the air quality in test rooms ventilated with realistic outdoor air supply rates, where combinations of high- and low-polluting wall, floor and ceiling materials were set up.

This paper discusses several issues concerning the CFD analysis or car parks during fire situations. A common modeling approach and given parameters are needed to obtain reliable results for the indication of the performance of the smoke evacuation systems. There are many modeling parameters which influence the results. CFD is a powerful tool that can be used for smoke evacuation simulation when properly used. There is a clear need for a simulation guideline that describes the following points:
- Demanded mesh sizes
- Detailed fire curve

The role of computational modelling as a development and engineering tool has recently become more significant. The major advantage is that modelling enables the testing of different geometries without having to build expensive test constructions. When a whole new building is in question, modelling is the only way to see inside it before its finished.