Upper room UV-disinfected mixed air use for chilled ceiling displacement ventilation system to enhance air quality and performance

Mohamad Kanaan, Nesreen Ghaddar, Kamel Ghali, Georges Araj, Walid Chakroun, Mohamad Darwish

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The chilled ceiling (CC) displacement ventilation (DV) system is one of the air conditioning systems that have shown effectiveness in providing air quality through supplying 100% fresh air. The CC/DV system effectiveness and economic viability has been increased when return fraction was recirculated in the supply air stream where the maximum CO2 concentration level does not exceed 700 ppm in the occupied zone. However, it is important to investigate whether satisfying the allowable level of CO2 inside the space ensures that the World Health Organization (WHO) requirement for bacterial and fungal count of less than 500 CFU/m<sup>3</sup> (14.2 CFU/ft<sup>3</sup>) is satisfied. If not, it will be interesting to study the maximum allowable return air ratio that provides good air quality in terms of acceptable CO<inf>2</inf> level and acceptable bacterial and fungal count and at the same time improves the energy performance. Since the CC/DV system relies on buoyancy effects for driving the contaminated air upwards, infectious particles will recirculate inside the upper zone before entering the return duct. Such increase in the residence of infectious particles in the upper zone, will allow the effective utilization of upper-room ultraviolet germicidal irradiation (UVGI) to clean the air before recirculating it. This paper uses an analytical model to investigate the effectiveness of upper-room UVGI mechanism for air disinfection when used with a mixed air CC/DV system. The simplified numerical model combines published multi-layer plume and three-zone mixing models to estimate the airborne bacteria concentration in the upper zone and occupied zone using the maximum allowable return air ratios. The results from this model are compared to a CFD simulation of the same room that incorporates the bacteria inactivation due to UV field.

Original languageEnglish
Title of host publication1st International Conference on Energy and Indoor Environment for Hot Climates
PublisherAmerican Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE)
Pages184-194
Number of pages11
Publication statusPublished - 2014
Event1st International Conference on Energy and Indoor Environment for Hot Climates - Doha, Qatar
Duration: 24 Feb 201426 Feb 2014

Other

Other1st International Conference on Energy and Indoor Environment for Hot Climates
CountryQatar
CityDoha
Period24/2/1426/2/14

Fingerprint

Ceilings
Air quality
Ventilation
Air
Bacteria
Irradiation
Disinfection
Buoyancy
Air conditioning
Ducts
Numerical models
Analytical models
Computational fluid dynamics
Health
Economics

ASJC Scopus subject areas

  • Environmental Engineering
  • Pollution
  • Building and Construction
  • Energy Engineering and Power Technology
  • Civil and Structural Engineering

Cite this

Kanaan, M., Ghaddar, N., Ghali, K., Araj, G., Chakroun, W., & Darwish, M. (2014). Upper room UV-disinfected mixed air use for chilled ceiling displacement ventilation system to enhance air quality and performance. In 1st International Conference on Energy and Indoor Environment for Hot Climates (pp. 184-194). American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE).

Upper room UV-disinfected mixed air use for chilled ceiling displacement ventilation system to enhance air quality and performance. / Kanaan, Mohamad; Ghaddar, Nesreen; Ghali, Kamel; Araj, Georges; Chakroun, Walid; Darwish, Mohamad.

1st International Conference on Energy and Indoor Environment for Hot Climates. American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE), 2014. p. 184-194.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Kanaan, M, Ghaddar, N, Ghali, K, Araj, G, Chakroun, W & Darwish, M 2014, Upper room UV-disinfected mixed air use for chilled ceiling displacement ventilation system to enhance air quality and performance. in 1st International Conference on Energy and Indoor Environment for Hot Climates. American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE), pp. 184-194, 1st International Conference on Energy and Indoor Environment for Hot Climates, Doha, Qatar, 24/2/14.
Kanaan M, Ghaddar N, Ghali K, Araj G, Chakroun W, Darwish M. Upper room UV-disinfected mixed air use for chilled ceiling displacement ventilation system to enhance air quality and performance. In 1st International Conference on Energy and Indoor Environment for Hot Climates. American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE). 2014. p. 184-194
Kanaan, Mohamad ; Ghaddar, Nesreen ; Ghali, Kamel ; Araj, Georges ; Chakroun, Walid ; Darwish, Mohamad. / Upper room UV-disinfected mixed air use for chilled ceiling displacement ventilation system to enhance air quality and performance. 1st International Conference on Energy and Indoor Environment for Hot Climates. American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE), 2014. pp. 184-194
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