AIVC - Air Infiltration and Ventilation Centre

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measurement technique

The measurement of air infiltration rates in large enclosures and buildings.

The report discusses the need for a proven method of measuring air infiltration rates in large enclosures in order to assess the need for and effectiveness of energy saving measures. The object of the research is to develop such a proven method. Some

Measurement of the air change rate and ventilation characteristics during short term transient phenomena

Different measurement procedures are available for the experimental assessment of air change rates inside ventilated enclosures. These mainly consist of tracer gas techniques and can usually be applied to steady-state or moderately transient conditions and when a continuous mixing of the indoor air is assured throughout the test. However, due to the relatively slow response of the gas analysers, none of these procedures can usually be applied to fast transient phenomena that last 15 minutes or less.

Segmental Equivalent Temperature Determined by Means of a Thermal Manikin : A Method for Correcting Errors due to Incomplete Contact of the Body with a Surface

The segmental equivalent temperature determined by means of a thermal manikin is often correlated with the local thermal sensation of people and is used for indoor environment assessment. It is also used to assess performance of heated/cooled/ventilated car seats, etc. However, the body of the thermal manikins used at present is not as flexible as the human body and is divided into body segments with a surface area that differs from that of the human body in contact with a surface. The area of the segment in contact with a surface will depend on the shape and flexibility of the surface.

Simplified measurement techniques for health visitors to assess indoor environments

There is research acknowledging that the home environment may be responsible for worsening respiratory conditions, especially for children. The indoor environment is a substantial source of exposure to pollutants e.g. environmental tobacco smoke. Apart from conducting specialised, costly and complex studies a method was needed to understand and assess indoor environments in the UK and how people could be encouraged to improve their indoor environment.

Measurements of air temperatures close to a low-velocity diffuser in displacement ventilation using an infrared camera

The authors have developed a whole-field measuring technique that allows the visualization of air temperatures and airflow patterns over a large cross-section. For that measurement, an infrared camera and a measuring screen placed in the airflow are used. Thanks to that technique, real-time images within large areas can be recorded and transient events can be captured. The method was applied to a flow from a low-velocity diffuser in displacement ventilation.

Some methods for measuring natural convection flows in ventilation applications

Two methods have been used for measurement of natural convection flows in a narrow vertical channel of which one wall is heated : a hot wire anemometer adapted to measurements in flows where temperature gradients exist (two hot wires with different overheat) and a method for attaining bulk flow information in boundary layer flows. Results from these two methods are compared.

Monitoring of a low-velocity air jet using computed tomography

Computed tomography consists in measuring chemical concentrations profiles in a room from the attenuation of a large number of laser rays and converting measurements in a two dimensional concentration profile by a reconstruction algorithm. This study shows the effectiveness of one of these algorithms (Low Third Derivative).

PIV measurements at the breathing zone with personalized ventilation

In order to identify the complex flow located at the breathing zone of a seated person exposed to the airflow coming form a PVS (personalized ventilation system) two techniques are used and compared : the PIV ( a two-dimensional particle image velocimeter) and the LDA (laser doppler anemometer) technique with a single point measurement, given by a cross section of laser beams.
The PIV technique appears a very interesting tool in studies aiming at identifying airflow in rooms or around objects.

Definition of airflow parameters from records of flow visualization using a fog

The paper deals with air flow visualisation using fog generators. This technique has been applied to show air jets boundaries in several cases, in order to design flow generating equipment in industrial buildings.

The philosophy behind the development of a new line of measuring instruments.

There is a wide choice of new technology to choose from when developing a new line of indoor climate measuring instruments. The paper describes the Dantec company's and the authors' vision for meeting the needs. The focus was primarily on the application. Efficiency has been chosen at the expense of versatility in the user interface. Also describes some indoor climate measuring examples.

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