A literature review shows that the actual trends to prediction of air flow in multizone buildings are not only due to economical reasons but mainly to indoor air quality, acoustical and thermal comfort improvements. During the last decade, almost fifty models have been developed in eight countries [1]-[4]. Except some models the analysis of interaction between HVAC systems and building infiltration is seldom studied [5].
A small test room has been built which is five times smaller than the so called Annex-20-room. Different kinds of tracers have been used for visualizing of flow patterns. Velocities, concentrations and mass transfer coefficients have been measured. The measuring instrumentation is based on thermal anemometry (hot wire probes) and a special ammonia-mass transfer method, respectively, in order to estimate the heat flux coefficient at the walls.
This investigation is concerned with the determination of velocity pressure loss-factors for HVAC system components using tracer-gas techniques. Experimental work was carried out using an HVAC system and k-factors for various components such as bends, branches, contractions, expansions and orifice were determined. Results were compared with measurements made using a pitot tube and values given in the CIBSE Guide and ASHRAE Handbook. The performance of different types of filters used in HVAC systems was also examined.
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