This paper describes tracer gas methods and equipment developed to measure infiltration and inter-zone air flow rates in New Zealand houses. Air flows in houses have been studied in detail, in order to understand the role of ventilation in controlling indoor moisture, and the role of air flows through the construction cavities in transferring mloisture to parts of the structure most sensitive to moisture. The main technical content of this paper, however, concerns an automated tracer gas detection and delivery system based around a gas chromatograph and an electron capture detector.
The COMIS workshop (Conjunction of Multizone Infiltration Specialists), using a multi-national team, is planning to develop a reliable, smooth running multizone infiltration model on a modular base. This model not only takes crack flow into account but also covers flow through large openings, single-sided ventilation, cross ventilation and HVAC-systems. The model contains a large number of modules which are peripheral to a steering program. COMIS can also be used as a basis for future expansion in order to increase the ability to simulate buildings.
A tracer gas technique for determining volumes and air flow rates in multi-cell systems with a single tracer gas is considered. Tracer gas is injected in all cells simultaneously according to a cetain pattern and the resulting tracer gas concentrations are recorded. We show how the volumes and flow rates can be identified from the measurements using the quadratic programming method. A characteristic of this method is that the unknown model parameters, i.e. the volumes and flows, can be determined subjected to given constraints.
This paper describes an experimental study of the buoyancy-driven flow and the associated energy transfer within a closed, halfscale stairwell model. It provides new data on the velocity, temperature, volume and mass flow rates of the air circulating between the upper and lower storeys. The results are presented for various heat input rates from the heater, located in the lower floor. For most of the data presented, heat transfer to the surrounding atmosphere takes place through the side walls.
An up-to-date design concept for office buildings results in a very low energy consumption and provides a better indoor climate at the same time. This new concept is based mainly on two design features: An extremely well insulated building envelope decouples the indoor climate from the outside climate to a high degree during all seasons and weather conditions. The second element of this new design concept is the HVAC-system: The source-dominated displacement ventilation provides a better comfort and, as a cosequence of its high effectiveness, is very economical.
Measurement methods based upon multiple tracer gas techniques have become an established branch of the study of air infiltration and interzonal air movements. Three general groups of techniques have emerged, namely constant concentration, constant emission, and decay. Of the decay type group of techniques, several methods of deriving airflows from measured concentration/time curves have been suggested.
Ventilation in a building enables to renew the air it contains by means of a natural exchange of air (depending on weather conditions and climate) or a forced exchange using mechanical appliances. This exchange of air must range between minimum air purity and maximum economical limit of dispersion (ventilating means cooling) without causing currents of air, unbearable for the people in the room, which would worsen thermal comfort.
The AIVC nowadays is an established Centre on infiltration and ventilation research. It is well known throughout the world. This position has not been reached easily. But years of hard working and critical managing of the Centre were a necessity. Goes on to discuss the future development of the Centre.
Displacement flow systems are becoming popular, especially in Scandinavia, for comfort ventilation. In these systems air is supplied near the floor at low velocity; the temperature of the supply air is a few degrees below that of the air in the room. The supply air is heated by persons and/or machinery in the room. Turbulent plumes are formed above these heat sources.
Canadian research into residential ventilation and combustion venting revealed that the installed performance of exhaust equipment, ducting passages, and site-built chimneys was largely unknown. It became necessary to establish actual characteristics in order to be better able to predict the safety and effectiveness of various ventilation measures. For this reason, Canada Mortgage and Housing Corporation (CMHC), the federal agency responsible for housing policy, had a research device designed and fabricated.
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