A typical commercial/institutional building is modeled using a computer program developed by ASHRAE as research project number RP-590. The RP-590 program output was used as input in a separate program written to calculate the CO2 concentration levels in the various zones of this typical building on an hourly basis for a one year cycle. This data allow one to see how VAV A/C systems affect the CO2 levels in each zone as the VAV boxes modulate in response to the thermal load.
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.
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.
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.
To properly evaluate the performance of ventilation system, the interaction among ventilation rate, indoor air-quality, and cooling/heating load should be analyzed. In this study, an integrated simulation tool based on TRNSYS will be suggested to analyze the performance of ventilation system. Some modules to calculate the changes in indoor concentration of pollutants with ventilation system and to decide the operation mode of ventilation system were newly developed. In addition, the developed modules were coupled with building load and heating/cooling simulation modules.
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