A new version of 'classification for indoor climate, construction and building material' has been published in 2001 in Finland, giving recommendation on ventilation systems and their cleanliness. Procedures to test values and check criteria are given.
The study characterised the mixing of tracer gas in three ventilation systems with two different airflow rates (totally outdoor air).The test procedure is presented and errors are calculated and compared.
Measurements of metabolic carbon dioxide concentration made in four classrooms in two schools are reported for both occupied and unoccupied periods. Measurements were taken for approximately one week in each classroom during the unheated season and the time-varying ventilation rates estimated. The results of the experiments show CO2 concentrations that are far beyond the guideline value of 1000 ppm (the maximum concentration during the occupied period was 3756 ppm). Calculated air supply rates vary from unacceptably low levels, to rates that are in line with guidance.
In the following, measurements of CO2 levels in seven classrooms in four schools are reported. Measurements were taken for approximately one week in each classroom during the heating season and the time-varying ventilation rates estimated. The results of the experiments show CO2 concentrations which are far beyond the guideline value of 1000 ppm (the average concentration during the occupied period was 1957 ppm). In some classrooms the level exceeded the range of the detector (4000ppm).
CFD calculations were performed in a ventilated room of 5.7 m2, with an air supply near the floor and an air exhaust near the ceiling on the opposite wall. Air flow rate and inlet temperature are 14.3 l/s and 22C. Calculation results show for example that a standing or seated occupant inhales air coming from the aera close to the floor, which flows upwards due to metabolic heating. A new index (IECI) was used to characterize the effectiveness of contaminant inhalation. The higher values of IECI in the room indicate the zones which the inhaled air comes from.
The study has compared experimental data and numerical simulation of air velocity for a room with jet diffusers to assess comfort conditions in the occupied zone. Comparison was mainly done in planes perpendicular and along the jet axis.Results allow to expand the use of the numerical approach during design to achieve high levels of environmental comfort.
The study presents the influence of three different air diffusion systems and furniture layout on comfort (PMV, PPD) and indoor air quality (ventilation efficiency). Results of CFD calculations have been validated using experimental results for one case on a test rig. Charts are given to help dimensioning.
Five different techniques of tracer gas measurement are reviewed in order to determine the total ventilation airflow rate as well as air distribution in the room, on site or in laboratory. Examples of applications are given insisting on the two most recent techniques.
The study examines the effect of diffuser, buoyancy and surface radiation on flow, in order to better understand the changes in room air flow due to the energy control strategy. Calculations have been applied on one room for two different ceiling air diffusers.
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