An experimental study on airflow characteristics and thermal environment with asymmetrically located heat loads and low-momentum diffuse ceiling ventilation.

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A4 Artikkeli konferenssijulkaisussa

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2018-06-05

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en

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Proceedings of Roomvent & Ventilation 2018, 2-5th of June 2018, Espoo, Finland

Abstract

Airflow characteristics were studied with asymmetrical heat load distribution and diffuse ceiling ventilation. The heat load was increased from 40 W/floor-m^2 to 80 W/floor-m^2, while the average air temperature was kept at 26±0.5°C. Experiments were carried out in a test chamber of 5.5 m length x 3.8 m width x 3.2 m height with omnidirectional anemometers by 1-hour interval. The heat loads consisted of two opposite workstations next to warm window panels in the perimeter area. The other side of the room was an open area describing a corridor zone. Both workstations had a seated test dummy with a laptop and a monitor. The results indicate that the mean air speed and the airflow fluctuation increase with heat load. Consequently, also the turbulent kinetic energy and the turbulence dissipation increase. However, the increased heat load had only a small effect on turbulence intensity. Therefore, draught rate increased significantly with mean air speed. In addition, the smallest length-scale decreased towards increased heat load. This thermal environment would be classified as the category B-C defined by the European Standard EN ISO 7730:2005, because the mean air speed levels were too high at increased heat load conditions.

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Keywords

thermal environment, heat load, buoyancy flows, airflow interaction, diffuse ceiling ventilation

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Citation

Lestinen, S, Kilpeläinen, S, Kosonen, R, Jokisalo, J & Koskela, H 2018, An experimental study on airflow characteristics and thermal environment with asymmetrically located heat loads and low-momentum diffuse ceiling ventilation. in Proceedings of Roomvent & Ventilation 2018, 2-5th of June 2018, Espoo, Finland . SIY Sisäilmatieto Oy, Roomvent & Ventilation Conference, Espoo, Finland, 02/06/2018 .