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.
This paper presents the experimental results of the comparative study of three Passive Cooling Systems (PCSs) for the natural conditioning of dwellings carried out in Maracaibo, Venezuela. An experimental platform has been built to study the thermal performance of PCS. It includes: two full scale test cells, a meteorological station and an automated data acquisition system. The results are analyzed in terms of Indoor Characteristic Temperatures (JCT), Mean Cooling Potential (MCP) and the Cooling Performance Index (CPI) of each PCS.
Natural ventilation can be a part of a strategy for a good indoor air quality. It can also be a way to realise night time ventilation during warm periods. In this latter case, the aim is to cool down the thermal mass of the building to obtain a better thermal comfort during daytime. Night time ventilation requires high ventilation rates and sufficient accessible thermal mass. The ventilation openings have to be well designed to avoid undesirable effects like rain, pollution and burglary.
Login