This paper presents the field experiments on the ventilation efficiency in an underground car park where high velocity fan-diffuser units were installed as shown in Photo 1. The concentration of SF6 were measured as tracer gas under the step up condition and the step down condition, and the ventilation efficiency such as the age of air were calculated from the rising curve and the falling curve of the SF6 concentration in the underground car park. The ventilation efficiencies of two cases were compared, i.e.
This paper presents the results of the numerical simulation on the ventilation efficiency and the residual age of air by using CFD in the underground car park in which the field measurement was conducted as shown in a previous paper. The agreement between the CFD result and the measurement one was observed at most of the measuring points. The detailed distribution of local air change effectiveness was examined with the results from CPD in this paper.
This paper attempts to provide a general basis for implementing the principles of pressure differentials to aid in providing more user friendly air quality in buildings. This is a new technology application to be added to the commonly used air changes and filtering for cleaner air. The success story of smoke control can now be used as a major strategy against pollution and disease control in buildings. Stale bacteria-infiltrated air can also be contained to its spaces of origin and exhausted from its sources in the building.
The emission factors from solvent based paint on stainless steel plates have been studied in three different climate controlled rooms. After equilibrium conditions had been achieved in these rooms, the results were practically the same. The study shows that the effects of sorption, changes in ventilation and air velocity do not affect the results, and it is thus possible to develop a calculation model which can incorporate emission factors.
Describes low energy houses which have been built at Lindas in Sweden. A traditional heating system has been replaced in the design by heat exchanger in combination with an exceptionally well insulated construction. The terraced houses maximise use of passive solar gains, while balconies and projecting eaves protect against excessive solar radiation during the summer. External walls are exceptionally well insulated and airtight. The ventilation system consists of a supply and exhaust air unit with a counter flow heat exchanger that provides 85% heat recovery.
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