An experimental investigation into the ventilation effectiveness of diffuse ceiling ventilation

Chen Zhang, Rune Andersen, Georgios Christodoulou, Marius Kubilius, Per Kvols Heiselberg

Research output: Contribution to book/anthology/report/conference proceedingArticle in proceedingResearchpeer-review

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Abstract

Diffuse ceiling ventilation is a novel air distribution concept, where the space above a suspended ceiling is used as a plenum and fresh air is supplied into the occupied zone through perforations in the suspended ceiling panels. Due to the low momentum supply, the airflow in the room is driven by buoyancy force generated by heat sources. The previous studies indicate that the diffuse ceiling ventilation system can effectively eliminate the draught risk in the occupied zone and provide a comfortable indoor environment even with low-temperature
supply. However, the effectiveness of diffuse ceiling ventilation in term of air quality has not been studied systematically. It is essential to investigate whether the ventilation system could remove the air-borne contaminants in an efficient way. This study was based on experimental measurement in a full-scale test room simulated an office condition. Contaminant removal effectiveness were measured with N2O tracer gas by step-up method. Two different contaminant sources were analysed, one was occupants also served as heat sources, and the
other was a point source located at floor level and 1.1 m height simulated the contaminant from floor finish and furniture. The measurements were conducted with different heat loads and air flow rates, which represented typical office operating scenario in the summer. When the contaminant released from occupants, mixing has been reached between contaminant and room air. In addition, the stronger the heat load, the higher mixing level was observed. When
the passive contaminant source was located on the floor, due to lack of buoyancy it was trapped in the lower zone and high CRE was observed in the occupied zone (above 0.6 m height). However, the thermal plume around occupant created an upward movement and brought the containment to the breathing zone. This local disturbance of the concentration distribution may affect the personal exposure significantly. Finally, the contaminant concentration was measured in the plenum, and the results indicated that no reverse flow from
occupied zone to the plenum occurred in all cases.
Original languageEnglish
Title of host publicationProceedings of the 39th AIVC Conference, 7th TightVent Conference and 5th venticool Conference : Smart Ventilation for buildings
Number of pages7
Place of PublicationAntibes Juan-Les-Pins, France
Publication dateSep 2018
Pages990-996
Publication statusPublished - Sep 2018
Event39th AIVC Conference: "Smart ventilation for buildings" - Antibes Juan-Les-Pins, France
Duration: 18 Sep 201819 Sep 2018
Conference number: 39
http://aivc2018conference.org/

Conference

Conference39th AIVC Conference: "Smart ventilation for buildings"
Number39
CountryFrance
CityAntibes Juan-Les-Pins
Period18/09/201819/09/2018
Internet address

Fingerprint

Ceilings
Ventilation
Impurities
Air
Thermal load
Buoyancy
Thermal plumes
Air quality
Momentum
Flow rate
Gases

Keywords

  • Diffuse ceiling ventilation
  • Ventilation effectiveness
  • Contaminant removal effectiveness
  • Experimental study

Cite this

Zhang, C., Andersen, R., Christodoulou, G., Kubilius, M., & Heiselberg, P. K. (2018). An experimental investigation into the ventilation effectiveness of diffuse ceiling ventilation. In Proceedings of the 39th AIVC Conference, 7th TightVent Conference and 5th venticool Conference: Smart Ventilation for buildings (pp. 990-996). Antibes Juan-Les-Pins, France.
Zhang, Chen ; Andersen, Rune ; Christodoulou, Georgios ; Kubilius, Marius ; Heiselberg, Per Kvols. / An experimental investigation into the ventilation effectiveness of diffuse ceiling ventilation. Proceedings of the 39th AIVC Conference, 7th TightVent Conference and 5th venticool Conference: Smart Ventilation for buildings. Antibes Juan-Les-Pins, France, 2018. pp. 990-996
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Zhang, C, Andersen, R, Christodoulou, G, Kubilius, M & Heiselberg, PK 2018, An experimental investigation into the ventilation effectiveness of diffuse ceiling ventilation. in Proceedings of the 39th AIVC Conference, 7th TightVent Conference and 5th venticool Conference: Smart Ventilation for buildings. Antibes Juan-Les-Pins, France, pp. 990-996, 39th AIVC Conference: "Smart ventilation for buildings", Antibes Juan-Les-Pins, France, 18/09/2018.

An experimental investigation into the ventilation effectiveness of diffuse ceiling ventilation. / Zhang, Chen; Andersen, Rune; Christodoulou, Georgios; Kubilius, Marius; Heiselberg, Per Kvols.

Proceedings of the 39th AIVC Conference, 7th TightVent Conference and 5th venticool Conference: Smart Ventilation for buildings. Antibes Juan-Les-Pins, France, 2018. p. 990-996.

Research output: Contribution to book/anthology/report/conference proceedingArticle in proceedingResearchpeer-review

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N2 - Diffuse ceiling ventilation is a novel air distribution concept, where the space above a suspended ceiling is used as a plenum and fresh air is supplied into the occupied zone through perforations in the suspended ceiling panels. Due to the low momentum supply, the airflow in the room is driven by buoyancy force generated by heat sources. The previous studies indicate that the diffuse ceiling ventilation system can effectively eliminate the draught risk in the occupied zone and provide a comfortable indoor environment even with low-temperaturesupply. However, the effectiveness of diffuse ceiling ventilation in term of air quality has not been studied systematically. It is essential to investigate whether the ventilation system could remove the air-borne contaminants in an efficient way. This study was based on experimental measurement in a full-scale test room simulated an office condition. Contaminant removal effectiveness were measured with N2O tracer gas by step-up method. Two different contaminant sources were analysed, one was occupants also served as heat sources, and theother was a point source located at floor level and 1.1 m height simulated the contaminant from floor finish and furniture. The measurements were conducted with different heat loads and air flow rates, which represented typical office operating scenario in the summer. When the contaminant released from occupants, mixing has been reached between contaminant and room air. In addition, the stronger the heat load, the higher mixing level was observed. Whenthe passive contaminant source was located on the floor, due to lack of buoyancy it was trapped in the lower zone and high CRE was observed in the occupied zone (above 0.6 m height). However, the thermal plume around occupant created an upward movement and brought the containment to the breathing zone. This local disturbance of the concentration distribution may affect the personal exposure significantly. Finally, the contaminant concentration was measured in the plenum, and the results indicated that no reverse flow fromoccupied zone to the plenum occurred in all cases.

AB - Diffuse ceiling ventilation is a novel air distribution concept, where the space above a suspended ceiling is used as a plenum and fresh air is supplied into the occupied zone through perforations in the suspended ceiling panels. Due to the low momentum supply, the airflow in the room is driven by buoyancy force generated by heat sources. The previous studies indicate that the diffuse ceiling ventilation system can effectively eliminate the draught risk in the occupied zone and provide a comfortable indoor environment even with low-temperaturesupply. However, the effectiveness of diffuse ceiling ventilation in term of air quality has not been studied systematically. It is essential to investigate whether the ventilation system could remove the air-borne contaminants in an efficient way. This study was based on experimental measurement in a full-scale test room simulated an office condition. Contaminant removal effectiveness were measured with N2O tracer gas by step-up method. Two different contaminant sources were analysed, one was occupants also served as heat sources, and theother was a point source located at floor level and 1.1 m height simulated the contaminant from floor finish and furniture. The measurements were conducted with different heat loads and air flow rates, which represented typical office operating scenario in the summer. When the contaminant released from occupants, mixing has been reached between contaminant and room air. In addition, the stronger the heat load, the higher mixing level was observed. Whenthe passive contaminant source was located on the floor, due to lack of buoyancy it was trapped in the lower zone and high CRE was observed in the occupied zone (above 0.6 m height). However, the thermal plume around occupant created an upward movement and brought the containment to the breathing zone. This local disturbance of the concentration distribution may affect the personal exposure significantly. Finally, the contaminant concentration was measured in the plenum, and the results indicated that no reverse flow fromoccupied zone to the plenum occurred in all cases.

KW - Diffuse ceiling ventilation

KW - Ventilation effectiveness

KW - Contaminant removal effectiveness

KW - Experimental study

M3 - Article in proceeding

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EP - 996

BT - Proceedings of the 39th AIVC Conference, 7th TightVent Conference and 5th venticool Conference

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ER -

Zhang C, Andersen R, Christodoulou G, Kubilius M, Heiselberg PK. An experimental investigation into the ventilation effectiveness of diffuse ceiling ventilation. In Proceedings of the 39th AIVC Conference, 7th TightVent Conference and 5th venticool Conference: Smart Ventilation for buildings. Antibes Juan-Les-Pins, France. 2018. p. 990-996