Measuring Filtration Efficiency Particle Indoor/Outdoor Concentration Ratio On-line

Hannu Salmela, Tapio Kalliohaka, Ilpo Kulmala, Jari Kataja, Matti Niemeläinen, Aimo Taipale

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review


    VTT has developed and installed indoor air measuring systems to determine the efficiency of supply air filtration of buildings in real operational conditions. The systems have been installed in air handling units of buildings in China and in Finland. The systems consist of air sampling, a valve mechanism, particle counters and a computer that controls the system and records the measuring data. The measurement of temperature, relative humidity and carbon dioxide of the air and pressure difference of the supply air filter is also incorporated. In one of the installations, the measuring data is sent wirelessly to a server, where the data is analysed. The measurement arrangements provide detailed information on the removal efficiency of the filter as a function of particle size. Particle concentration measurements of the supply air and the return air provide ways to assess the indoor/outdoor ratio of the indoor air impurities, leakages in the building envelope as well as indoor sources. The results provided by the system showed that indoor air particle concentration can be reduced significantly. However, this calls for expertise and understanding of the dynamics of the ventilation system. Installing more efficient supply air filters resulted in extremely low particle concentrations in the supply air. In the future, particle concentration, CO2 and energy consumption should be optimized simultaneously in a HVAC control system. The measuring system may have a vital role in monitoring and controlling the operation of more intelligent and cost effective HVAC systems. This is especially true, if the price of the major components of the measuring system continue to decrease.
    Original languageEnglish
    Title of host publicationVentilation 2015
    Subtitle of host publicationProceedings of the 11th International Conference on Industrial Ventilation
    Publication statusPublished - 2015
    MoE publication typeA4 Article in a conference publication
    Event11th International Conference on Industrial Ventilation, Ventilation 2015 - Shanghai, China
    Duration: 26 Oct 201528 Oct 2015
    Conference number: 11


    Conference11th International Conference on Industrial Ventilation, Ventilation 2015
    Abbreviated titleVentilation 2015


    • indoor air quality
    • filtration efficiency
    • I/O ratio
    • on-line measurement


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