air flow

The paper shows that age analysing techniques are an excellent tool to assess ventilation effectiveness. It is important to differentiate between air exchange effectiveness and contaminant removal effectiveness, having continuous generation of contaminants. Only when a source is homogeneous andpassive, are the age of the air and the contaminants in the room equal. However, the air exchange effectiveness accounts for the removal effectiveness of the contaminant left in the room when the generation stops.

A general multi-chamber model is presented and explored from the viewpoint of air quality studies. The model involves the following key concepts: purging flow rate and age distribution of both air and contaminants. From the physical and mathematical properties of the model, are deduced estimates of themagnitude of, and the relations between, the key concepts. The practical use of the model is illustrated.

Using meteorological and physical data, a model simulating pressure and air mass flow distribution in buildings was produced using the method of non-linear networks. It was used to study wind and buoyancy effects on mechanically ventilated buildings. Contents include: natural ventilation in high rise buildings with and without air-handling equipment, a study of a hospital, and calculation of the annual heat load for ventilation.

To update the National Association of Home Builders Thermal Performance Guidelines, models were developed, representative of the new houses being constructed in each American state. The models define the number and types of windows and doors,

This paper explains the physics of air flow patterns, the aerodynamics of buildings and their implications for effective ventilation. Ventilation influenced design strategies of sunshading, daylighting and landscaping are discussed.

A survey of air flow patterns established in reliable laboratory experiments and field studies, with their original sources.

Use of computers for simulation of air flows in buildings, leading to production of a mathematical model for analysing the stability of ventilation systems subjected to external forces, and for simulation of heating systems toproduce a mathematical model of heat release and water flow in radiator systems. Investigation of fire ventilation.

Using meteorological and physical data, a model simulating pressure and air mass flow distribution in buildings was produced using the method of non-linear networks. It was used to study wind and buoyancy effects on mechanically ventilated buildings. Calculations were made for a naturally ventilated high rise building for varying permeability distributions and air flow resistances of the building envelope, using data from real buildings and from previous cases described in the literature.

Demonstrates that complaints by office staff about their physical environment are not necessarily caused by physical deficiencies. Trying to reduce the level of complaints by adjusting heating ventilating and air conditioning (HVAC) systems can therefore be an unrewarding task. Greater attention needs to be placed on - communications between management, those responsible for running HVAC systems and staff. Staff need the feeling that they can influence, if not control, their environment. Staff should also have more realistic expectations about their thermal comfort.

An account is given of what the kindergarten staff wrongly believed caused the problems and what measures they carried out in an attempt to solve them. On the spot measurements showed however what the real main cause of the problems was. Results from the comprehensive measurements of CO2 concentrations andother ventilation performance criteria in a room occupied by 12 children and 3adults are then presented.