LoginTracergases provide a way to determine airflows in different situations. In some cases it is the only way to get quantitative information.
12th AIVC Conference - Ottawa, Canada - 24-27 September 1991
The 12th AIVC Conference - Air movement and ventilation control within buildings, was held in Ottawa, Canada, 24-27 September 1991.
Contains 88 papers.
Volume content
This paper illustrates the principles of demand controlled ventilation systems (DCV) as applied to office buildings.
The reliability of infiltration and air movement data obtained from single tracer gas measurements in large spaces. | 1991 | English
The methods available for the measurement of air infiltration and air movement in large industrial halls are restricted by the size of the building and the nature of the operations which take place within it.
Ventilation flow analysis - flow visualisation and LDA measurements in water scale models, validation of numerical results. | 1991 | English
Within the frame of the IEA Annex 20, laboratory and numerical experiments were conducted in order to study the flow within an isothermal parallepipedic testroom (L x W x H = 4.2 m x 3.6 m x 2.5 m).
The performance of a system for demand-controlled ventilation was investigated for a period of 1.5 years. Presence sensors of the passive infrared type are used to control the ventilation rate in each classroom.
The simulation of infiltration rates and air movement in a naturally ventilated industrial building. | 1991 | English
This paper describes the application of numerical models to predict the ventilation rate and internal air movement patterns for a naturally ventilated industrial building and compares the results with measured data.
A new algorithm for the continuous measurement of variable air change rates with tracer gases will be presented. It differs from the constant concentration method by allowing the concentration level to vary according to the air change rate.
Knowledge of air movement within a building is often a condition for solving problems with the spread of pollution.
Tracer gas tests were conducted on a five-storey apartment building to determine the air and contaminant flow patterns within the building.
A literature search was performed to gain as much knowledge as was available on ventilation, indoor air quality sensors and demand controlled ventilation (DCV) strategies.
This speech comprises a summary of two publications from the Swedish Council for Building Research (BFR); the knowledge survey "Buildings and Health" (BFR T4:90) and "Indoor climate and energy husbandry" (BFR G5:90).
Airflow rates are directly affected by the amount of open area and consequently by the inhabitant behavior with respect to window opening.
Zonal models are a promising way to predict air movement, in a room with respect to comfort conditions and gradient of temperature, because they require extremely low computer time and may be therefore rather easily included in multizone air movem
Ventilation control of IAQ, thermal comfort and energy conservation by CO2 measurement. | 1991 | English
The use of indoor carbon dioxide levels is a good method for controlling indoor air quality in office buildings.
Once the flow-pressurization characteristics of a building are known, the largest uncertainty in predicting air infiltration is the effect of wind shelter from nearby buildings.
Demand controlled HVAC-systems have many advantages. The principle is to optimize comfort and to minimize energy consumption simultaneously. In modern office buildings, indoor temperature is very often a useful control parameter.
Natural ventilation of dwellings is commonly applied, especially in mild and moderate climates. The disadvantage of natural ventilation is the poor control of both flow directions and flow rates within the ventilated building.
A "HESCO"-type diffuser was selected as an example for the validation exercise in the IEA Annex 20 project (Air flow pattern within buildings). It consists of 84 small round nozzles that are arranged in four rows in an area of 0.71 m x 0.17 m.
Seen from the AIVC Technotes 21 and 28, Ventilation Efficiency is still a complex concept. As well for measurements as for simulations.
A test room with a Displacement Ventilation System was built. Temperature control was provided with a DDC (Direct Digital Control) System, controlling the air volume and the air inlet temperature.