This paper presents the results of a computational and experimental study to assess the possible benefits of using mathematical modeling techniques for cleanroom design. A two-dimensional modeling visualization has been used for each of the cases studied. This has the advantage that its relative cheapness allows more design variations to be analyzed than would be possible with a three-dimensional method. Full-scale measurements were also taken in the cleanroom which was the subject of the modeling exercise.
Outlines some of the principles behind air driven aspects of moisture in buildings and illustrates how calculation methods and mathematical modelling techniques may be used to both predict and remedy associated problems. Primary remedies include a reduction in the generation of moisture, ensuring thermal integrity of the building and providing adequate ventilation. The use of dehumidification may also have a role to play. Mathematical models offer an inexpensive method for assessing design ideas at an early stage of development.
This paper reviews the work carried out in the Netherlands on moisture problems. In current air flow simulation models for buildings, moisture transfer and diffusion in and between rooms are not taken into account. The aim of the research project is the development of an integral hygrothermal model in which the above mentioned aspects are incorporated.
This is a review paper addressing the current state-of-the-art. Concerns that motivate studies of the indoor environment are reviewed in the introduction. The source and typical diurnal variations of the concentration of several air contaminants are discussed in the section on characterization. A dynamic model is described in the section on indoor air quality modelling. Indoor air pollution control techniques are addressed in the last section.
This paper describes the development of a computational air flow modelling technique, and identifies applications within clean room installations. Details are given of a validation exercise in which air flow patterns and velocities for a number of simple 2-dimensional configurations were both measured and predicted. The good agreement between measurements and predictions clearly demonstrates the usefulness of the method.
This study used a constant concentration tracer gas measurement system to measure the air infiltration rate of three modules simulating residential buildings in Canada. The results obtained were compared with computer predictions.
Large, multicelled and naturally ventilated buildings pose many inherent problems for the measurement of overall infiltration rates using tracer gases. Considering a single tracer gas decay technique, the most obvious problems are: (a) local variations in infiltration, (b) imperfect internal mixing of the air, and (c) practical difficulties in distributing (ie, seeding) the tracer gas and subsequently obtaining air samples.
Infiltration heat loss has become more important in the energy loss of modern buildings. It depends on a variety of factors. Computer analysis points to the effect of storey number, ground plan features and exhaust ventilation systems. Different rooms exhibit infiltration heat loss maxima at different outdoor temperatures.
Twelve energy-efficient houses in Eugene, Oregon, USA, were measured for effective leakage area using blower door fan pressurization. Air exchange rates over a period of several hours were determined by tracer gas decay analysis.