A problem in a livestock building ventilated in the system with wall inlet at two sides is wind effects to the indoor air flow patterns. The in-proper inlet jet penetration profiles may cause draught at occupied zone and unnecessary stress of animals. The wind effects on such a system can be reduced by applying windbreak to the inlets from design point of view. However, a remain issue is if the effect could be reduced by regulating inlet opening and how to perform the control operation.
A data acquisition system which uses a computer provides a more useful analysis system. Since the processing speed of computer is continuously increasing, the information than it is possible using conventional data acquisition systems. However, the raw measurements also include the signal noise which may lead to difficulty when the signal is analyzed. This work assesses an algorithm for removing possible signal noise, usually with high-frequency, from the measurement of tracer gas concentration.
Solar chimneys are often used to extract air from a building by thermal stacks, while subfloor plenums are used to passively cool air before it is supplied to a building. This paper examines the overall flow pattern in buildings with both solar chimneys and subfloor plenums. For a multi-zone flow system in which each zone has only two effective openings, an analytical solution is derived. A sufficient condition for upward flows to occur is derived from the analytical solution.
Air change rates in a cross-ventilation model were measured from the decay curves of video image signals obtained by the step down method assuming perfect mixing of tracer mists inside the spaces. Wind tunnel test results led to the following conclusions. 1) Ray extinction due to lighting scattering did not affect the measurement accuracy of the air change rates in the two-dimensional model. 2) Tracer mists in a diameter between 0.25 μ m and 2.0 μ m produced the same measurement accuracy.
We present a series of analogue laboratory experiments of the transient exchange flow between a room filled with warm air and a cold exterior following the opening of a doorway. Our experiments suggest that the time-scale for mixing the fluid in the room below the top of the doorway is independent of the door height. We then describe the steady-state two-layer stratification that is established when, in addition to the exchange flow, a localised heat source provides heat at the base of the room.
Studies of airflow between two adjacent spaces of building were carried out using CFD simulation. The results of CFD simulation were validated against test data set obtained from full-scale experimental tests. The agreement and discrepancy between the prediction and measurement results were discussed. Further numerical exercises were carried out to study under the conditions that were difficult to achieve by experiments and the results obtained were supplemented to the understanding of convective heat transfer between adjacent rooms.
This investigation was carried out on a mechanically ventilated office building with a high prevalence of occupant symptoms. The commonest complaints were of dry air, stuffy air and noise. Occupant symptoms, however, were most strongly associated with reports of dusty air and static electricity. Allergic and asthmatic people suffered the most. Cleaning standards were high, and upgrading the air filters failed to give improvements in occupant symptoms. Air flows to the rooms were adequate, but air movements in the rooms were poor.
A systematic analysis of recently constructed dwellings in the Flemish Region has been undertaken within the SENVIVV-project (1995-1998). In total 200 dwellings have been examined in detail. The study involved various aspects: energy related building data (thermal insulation level, net heating demand, installed heating power, .. ), indoor climate (temperature levels in winter and summer), building airtightness, ventilation, appreciation of the occupants, . . . This paper especially focuses on the results for thermal insulation, airtightness and ventilation.
The purpose of this work is to see the influence of the heat preservation in the cold season and also to show the building material influence on the indoor radon concentration in dwellings. Three methods were used to measure the radon content in houses and buildings (workplaces). The results of measurements show that in the winter season the indoor radon concentration is about 2 times higher than in the summer season for these regions from Transylvania.
A comprehensive concept for an energie and comfort orientated retrofitting is realised for an office high rise building ,,BS 4" (on campus at Braunschweig Technical University). This master plan will take the form of a research and developement projekt; a pilot realisation will be carried out on the 10th floor.
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