Natural ventilation studies were carried out within the frame of PASCOOL EC Research Project. Research on this topic included experimental and modelling work aiming to fill the existing gaps in our knowledge of indoor air conditions in naturally ventilated buildings. Experiments were carried out in full scale and test cell facilities during the summer period. Single sided and cross ventilation as well as air flow through large internal openings were the basic topics that were studied. Existing models were validated and new ones were developed.
Many modern buildings in the Nordic countries have mechanical ventilation. Passive stack ventilation is, however, an accepted ventilation system in the Nordic countries according to the current building codes. The building authorities need to be able to supply guidelines on natural ventilation systems in modern buildings, in order to fullfill the requirements on a healthy indoor climate at a reasonable energy cost. Therefore a project was initiated by the Nordic committee on building regulations.
Wind pressures can significantly affect ventilation performance. However often they are overlooked in the design of a naturally ventilated building, with buoyancy forces presumed to offer the worst case scenario for design. The result is that airflow patterns and the ventilation performance of the building is often different from the design intent. Successful natural ventilation design requires careful consideration of the building form, and so must involve the architect at the early stages of fabric development.
Natural ventilation is being applied to an increasing number of new buildings to minimise reliance on mechanical ventilation and so reduce emission of greenhouse gases. However, passive stack ventilation (PSV) systems are currently designed without incorporating heat recovery leading to significant wastage of energy. Heat recovery systems have not been used in naturally-ventilated buildings because the pressure loss caused by a conventional heat exchanger is large compared to the stack pressure and could cause the ventilation system to fail.
This paper describes the ventilation analysis undertaken during the design of a new music centre for which it was desired to avoid the use of air conditioning and conventional ducted mechanical ventilation. The main objective was to predict the thermal comfort of occupants in the centre's main auditorium during summertime performances. The analysis was done using computational fluid dynamics (CFD) and a dynamic thermal model.
The project described in this paper has performed simulations using a multi-zone air flow model (4(COMIS)) of three different passive stack ventilation systems. The objective of the simulation calculations was to evaluate system performances and to make suggestions for possible improvements of the systems.
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