Describes the network procedure for calculating the most energy-conserving and economical form of natural ventilation of a building. Provides application examples in the form of the determination of mass air flows through doors and windows and cracks in industrial work sheds. Provides the results of a calculation of crack ventilation in winter with mechanical ventilation with positive pressure, plus optimisation of air flow through a cooling bed for hot rolled steel sections.
Development of infiltration and interroom airflow calculation methods, driven by a concern for indoor air quality have led to a computer simulation of interroom contaminant movement. The model, which assumes fully mixed room air, shows that open doorways provide rapid mixing between rooms in buildings using forced air heating. It also confirms that it is most energy efficient to remove the contaminant nearest its source. Detailed modeling of the variations in contaminant concentration within a room is not presently feasible for long term energy analysis simulations.
The objective of this paper is to highlight the range of air infiltration and ventilation models that are available to the designer and to indicate the appropriate level of associated computer hardware that is necessary to support these modelling methods. The description begins with a discussion on simple empirical methods intended for basic design calculations. The applicability of these methods is discussed and some of their shortcomings are highlighted.
In order to obtain means for determining realistic convective heat transfer coefficients, a hierarchy of interacting and interdependent calculation methods have been developed by the authors. Both higher and lower level models have been used to develop and verify an 'intermediate level' computer code, which formed the basis for generating input convective heat transfer data for dynamic building models. The contribution considers the computation of convective heat exchange within three-dimensional, rectangular enclosures when buoyancy effects are significant.
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