The computer-aided ventilation system design requires the programming of a large number of empirical tables and observations on the use of mathematical expressions which describe numerous ventilation parameters. In order to use computers with efficiency and to reduce programming inessentials, a set of numerical approximations are developed. These expressions are divided intotwo categories: 1) external variables and 2) system variables. The external variables are basically the duct resistance calcultions.
A mathematical model was used to describe the natural ventilation of a modern residential building for various building construction and meteorological data. The calculations showed that exhaust air shafts have a very positive influence and that separate consideration of wind and stack effect on thenatural ventilation of buildings leads to a wrong interpretation. Both major influences must be considered together.
Describes the measurement of infiltration in each of the seven rooms of a house over the period from November 1983 to January 1984 with occasional use of mechanical exhaust ventilation. Nitrous oxide was used as the tracer gas. External meteorological conditions were also recorded. The measurement principles are outlined and detailed results presented. Various mathematical models are assessed in comparison with the measured data.
Outlines the principles of air flow in buildings: the driving forces of wind and thermal pressure; laminar and turbulent flow; and the effects of the building geometry. Reviews the existing mathematical models of air flow and provides worked examples for a house and a multi-storey building.
A survey of mathematical models of air flow and of ventilation efficiency. Measuring equipment for laboratory experiments is described and the limitations and potential uses of the models are discussed.
This study deals with natural heat transfer through apertures between two adjacent rooms. A one-dimensional model has been developed to determine the flow rate and enthalpy rate transferred through each aperture as well as the vertical temperature profile in each room. Results show that flow rate and enthalpy rate vary quasilinearly through time. Temperature profiles show a high thermal stratification depending on the relative location of the apertures. Experiments have been performed in a test apparatus using water. Temperatures have been measured.
A mathematical model, CLIM, is used to compare constant air flow ventilation with adjustable ventilation controlled by indoor relative humidity. Exhaust air flow varies in a ratio of 1 to 4 between 40 and 75% of relative humidity and the mean annual air flow is divided by 2 in comparison with a classical mechanical ventilation system.