A Compact Equipment for Air Renewal Survey (CESAR) has been developed by the Ecole Polytechnique Federale de Lausanne. The device has been designed for simultaneous analysis of up to 10 different inhabited rooms over extended periods of time (days or weeks). The constant concentration tracer gastechnique was used for the first survey done in the South rooms of the LESO building. Mean outdoor to room flow rates of between 1 and 40 m3/h were found.The mean building to room air flow was found to be 5 m3/h for rooms with only one communicating door with the rest of the building.
The ventilation of a large room is often achieved by supplying inlet air from a small side-wall mounted opening. The velocity distribution in a typical room with a small circular inlet opening close to the ceiling is described. The supplied air forms a wall jet below the ceiling which is easy to describe in terms of velocity distribution, entrainment, etc. The jet is deflected at the end wall opposite the supply opening and the resultant flow in the lower part of the room - the occupied zone - has a rather complicated structure.
The state of practice in Canada, as described in the literature, concerning ventilation, air distribution and air quality in warehouses and light industrial buildings is reviewed. There is little documented field information available. Modelling processes have not been developed which can provide thenecessary detail. Measurement of air flows, both in the field and in models, is difficult. The regulatory environment in Canada allows considerable innovation in developing conservation procedures.
The multiple tracer gas technique developed at UMIST has been applied to the measurement of roof-space ventilation rates and house to roof-space air movement, for various types and combinations of roof-space ventilation. It has been shown that ridge tile ventilators, whilst increasing roofspace ventilation rates at low wind speeds, also significantly increase house to roof-space airflows over the whole range of wind speeds. This has implications not only in terms of energy wastage, but, more significantly , in terms of increased moisture rates to the roof-space.
For more than two years a series of detailed air infiltration measurements have been conducted over the complete yearly weather cycle on two identical side-by-side test houses in Gaithersburg, Maryland, USA. These measurements have been part of a broad study of the interaction of air infiltration , indoor air quality and energy in tightly constructed, well-insulated homes. The standard method of collecting air infiltration data throughout the study has been tracer gas decay. Operation of the duct air circulation fans has transformed each house into a single well-mixed cell .
Reviews the papers on air infiltration and ventilation research presented at the ASHRAE annual meeting held in Honolulu, Hawaii, in June 1985. The twelve most significant papers on multizone infiltration and air leakage are discussed at length and other infiltration-related papers mentioned. Authors' abstracts for the twelve symposium papers plus seven technical papers are presented.
Several infiltration models treat the complexity of air flows in multizone buildings, but most of them are written as research tools and are not generally available or user-friendly. Professional engineers and architects are in need of a simplified multizone infiltration model. This paper describes the first step in Lawrence Berkeley Laboratory's development of a multizone infiltration model for calculating the air flow distribution of a building without using any iteration procedure.
A Compact Equipment for Survey of Air Renewal (CESAR) was developed at the Ecole Polytechnique Federale de Lausanne in Switzerland. Controlled by a microcomputer, this apparatus uses tracer gas methods ( decay, continuous flow or constant concentration). Up to ten different locations in inhabited rooms can be monitored simultaneously over extended periods of time, using mainly the "constant concentration" technique. Several air renewal surveys were carried out on different inhabited buildings.
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