Shows the results of a study of the effects of turbulence upon ventilation. Controlled fluctuating air flows were directed upon openings in the side of acube simulating a building. The relationship between the turbulent characteristics of the air flow and the ventilation rate in the building modeare examined. Mean windspeed and the turbulent velocity and intensity of the air flow were measured with a thermocoupled anemometer. Resulting ventilation rates were measured by means of tracer gas decay, using CO2 as the tracer and an infra red analyser to monitor the decrease in concentration.
This is the second part of a study on natural ventilation in functional buildings. Reports the results of 23 measurements on a number of partitions, internal walls and one brick built internal wall. Measurements were made in 4 buildings. For the largest leakages measured in these 4 buildings, a strong influence was observed on the ventilation of neighbouring rooms. The opening of a window in a room has notable consequences on the ventilation and air flow in the other rooms. The measured air leakages ranged from 0038 to 0.068 m2 for a wall and .0131 -.0529 m2 for a room.
Deals with the problems of open building passages and tunnel like entrances caused by thermal influences and wind currents. Shows advantages of air screening, especially where high pressure differences occur.
Describes a calibration technique to relate the air flow rate through a blower door to the fan speed and pressure difference across the door. To obtain an accurate and well-documented calibration of pressurization devices, a facility was designed and constructed at the US National Bureau of Standards. This accurately determines the flow rate through the fan as a function of fan speed, air density and pressure difference across the fan.
Considers a building with an arbitrary number of point and line heat sources at the floor. Fresh air flows in the room through windows, warm air leaves through roof louvres. To model the complicated flow field, the building issubdivided into several regions. Mass, momentum and energy balances are set up for each region. Well-known results are used for turbulent plumes and wall boundary layers due to natural convection. Pressure drops across entrance and exit openings have to be compensated by buoyancy forces.
Describes a recent survey of a large ink manufacturing works in an effort to solve thermal comfort problems by improving the ventilation of specific areas of the plant. Six buildings were investigated. Illustrates them diagrammatically and explains the ventilation solutions recommended. Explains the base of the estimated construction and installation costs.
Discusses the mechanisms available for "single-sided" ventilation - ie when ventilation is achieved by the exchange of air through windows on one side of a space rather than by cross-ventilation. Describes a simple approach to its prediction based upon a combination of theoretical modelling, wind tunnel testing and tracer gas measurements made in full-scale buildings. Describes wind tunnel and full scale measurements which show the effect of degree of opening, window type and combinations of windows on the magnitude of ventilation rate.
Discusses different ways of defining and comparing ventilation efficiency. It can be defined in absolute values ie the ability of the system to decrease the concentration of impurities in proportion to the maximum concentration. A time consta
Presents a model for computing the infiltration and air flow between rooms of a multi-room building in terms of basic principles of fluid mechanics. This model has been incorporated into a comprehensive loads-predicting computer program. Air flo
There are several reports on studies of wind tunnel experiments and calculations on the response of air flow at an opening against the periodic variation of wind velocity and pressure. In these studies, the fluctuating components of natural wind velocity have been treated definitely. In this paper, theoretically derives the probability density function from a probabilistic model of wind velocity around the buildings, the consequent wind pressure, and the resulting ventilation rate and contamination concentration.
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