The thermal effects of air flows in building structures have been analyzed by computer simulation. Some laboratory experiments have also been carried out concerning natural convection in closed and semi-open cavities filled with fibrous insulating material. Three different flow systems in building structures have been studied: natural/forced convection in open/semi-open (permeable cold surface) 2-dimensional insulation structures, heating of infiltrating air in cracks and diffusive infiltration.
Fifty-nine owners/occupants of electrically heated houses in the Denver, Colorado area have, for about ten months, been participating in a study sponsored by the Electric Power Research Institute (EPRI) to determine theeffect of air infi
Several empirical models of house air infiltration, available from the literature, were reviewed and evaluated. Without exception, the limitations, inherent in these models, were found to stem from inadequate accounting of the interactive forces controlling air infiltration. In general, each of the available models was found to accurately reflect the specific real case used for verification, but extension of the model to other structures and situations was found to be totally inadequate.
One important factor in the spread of airborne infection must be the movement of the air itself i.e. the ventilation, although an exact correlation of it with the risk of infection has yet to be found. As part of an infection survey in a hospital ward we made a detailed study by physical methods of the movements of the air and of the transport of particles by this means. A description is given of the methods employed.
The problem of describing quantitatively the effective ventilation in a room when the air within the room is imperfectly mixed is discussed. It is suggested that the protection afforded by the ventilation to any given position against air
Unnecessary air infiltration ,draftiness, in buildings can be a major cause for excessive energy consumption. A method for using sound to locate, for subsequent sealing, the openings of air infiltration leakage paths in buildings has been investigated. The results of pertinent analytical studies, laboratory experiments, and field applications of this acoustic location method are reported, and a plan is provided to encourage national implementation of the method.
This paper describes the experimental techniques devised to measure the necessary parameters on installed heating systems. With these data the seasonal performance of a heating system can be computed. The effectiveness of various operating and system modifications can then be predicted. Thecalculated effects of some modifications are presented in a companion paper.
The use of lightwells and courtyards for natural ventilation in high-rise buildings is exaimed using both wind tunnel and field measurements of the pressures and neutral pressure zone caused by wind and temperature differences. Though air flow patterns are complex for complex building designs, air exchange rates in lightwells and courtyards were generally seen great enough to assure clean air for natural ventilation via air infiltration. However the cost of land in urban settings will probably make mechanical ventilation systems the economic choice.
This report contains a brief description of an air infiltration measuring device jointly developed by the National Bureau of Standards and Princeton University's Center for Environmental Studies. The device maintains a constant concentration of a tracer gas (SF6) in each room of a structure by injection, and relates the infiltration rate for each room to the rate of gas injected. Specifics of construction and use are included.
The purpose of this research project is for the Thermal Engineering Section of NBS to conduct air leakage measurements on selected large buildings tovalidate calculation formula developed by Shaw and Tamura, (see Shaw, C.Y., and Tamura, G.T., 'The Calculation of Air Infiltration Rate Caused by Wind and Stack Action for Tall Buildings', ASHRAE Trans., Vol. 83 part 2).
Login