This paper treats the structure of models for predicting interzonal airflow and contaminant dispersal in buildings. It will discuss the mathematical structure of such models, the use of modem data structures, the application of structured program techniques and the use of object-oriented structures for the development of users interfaces and building description processes.
This paper describes the use of tracer-gas techniques to measure airflow in a rectangular duct and a HVAC system. Experimental procedures are discussed for the application of the constant injection, pulse injection and decay techniques using N2O andSF6 as tracer gases. This paper also describes a new tracer-gas system with variable sampling speed which was used to measure the decay of tracer-gas concentration. A comparison is presented between tracer-gas measurements and those made with a pitot tube and a hot wire anemometer.
In an experimental facility, we studied the performance of a task ventilation system designed for use in office buildings. With this system, occupants can adjust the flow rate and direction of air supplied to their work space through four floor-mounted supply grills. Air typically exits the ventilated space through ceiling-mounted return grills. To study indoor air flow patterns, we measured the age of air at multiple indoor locations using the tracer gas stepup procedure.
A new European norm for measuring the heat transfer rate of radiators is under discussion [ CEN TC 130 ]. This testing can be done either in a closed chamber with cooled walls or in a open chamber with a controlled air supply. The air flow pattern around a typical radiator is calculated for both types of chambers. The calculation is done with the program PHOENICS, a finite volume program that solves the conservation equations for mass, momentum and energy. For turbulence, the k-E model is used with the Lam-Bremhorst correction for low Reynolds numbers.
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