In the frame of a Swiss research project, a passive tracer gas technique for the determination of multizone air flow and contaminant transport in buildings was tested, based on previous work in several other countries. First emission characteristics of the three different sources (PMCP, PMCH and o-PDCH) and the adsorption characteristics of the passive samplers (standard Perkin-Elmer AD400 adsorption tubes) were established.
This work is centered on the transient analysis of natural ventilation provided by a single side opening when only indoor-outdoor temperature differences are present (no wind). Using both simplified "engineering" models and a CFD commercial code (2D), different cases have been examined by varying indoor-outdoor temperature difference, window size, and including or not a heating appliance in the room.
In an air-conditioned office building, the ventilation air is normally mixed with the return air from the room in the air-handling unit. Therefore, the value of the air exchange efficiency defined by age of air is usually about 1.0, which is close to the perfect mixing case. If the fresh air and air-conditioning air are supplied separately, it is possible to increase the value of the air exchange efficiency at the breathing zone if the former is supplied directly to the breathing zone. In this paper, the results of the CFD investigations for the ventilation tower system are described.
The Particle Streak Tracking System (PST) is a fast method to measure two- and three-dimensional velocity fields in room air flows with measuring areas up to 5 m2. The two-dimensional method works with a single pulsed white light sheet and one digital camera. For three-dimensional velocity measurements in planes a laser light sheet system using three separate laser sheets with two different wavelengths and two CCD-cameras is employed. To visualise the flow helium filled bubbles are used. A description of the set-up will be given and the data evaluation process will be explained.
This paper reports on an investigation of the use of an innovative earth tube ventilation system designed to improve the internal comfort conditions without the need for mechanical cooling. The numerical model and computer simulation developed for the prediction of air and soil temperatures has been made. The paper demonstrates the accuracy of this model and describes the results of analysis.
Surveys in several office buildings have shown that crowded work places, job dissatisfaction and physical environment are the main factors affecting productivity. the data was produced and analyzed using occupational stress indicator in conjunction with the analytical hierarchical process. thermal problems, stuffiness, sick building syndrome factors and crowded work places were most frequent complaints. the results suggest that the productivity could be improved by 4 to 10% by improving the office environmental conditions.
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