Publication date: July 2016
Source:Building and Environment, Volume 103
Author(s): Yi Yang, Alvin C.K. Lai, Chunliang Wu
Disinfection efficiency of upper-room ultraviolet germicidal (UR-UVGI) fixtures system is of key importance to control and reduce indoor airborne inflections. One of the key factors to determine the disinfection efficiency is to quantify the fluence rate of the system. In this paper, a previously developed mathematical model was firstly modified to calculate the fluence rate of the multiple UR-UVGI fixtures system. The calculated fluence rate agreed well with measured data of two UR-UVGI fixtures. Secondly, the ultraviolet equivalent air-exchange rate of the multiple UR-UVGI fixtures system on different airborne microorganisms was investigated by using the improved drift flux model incorporating with the calculated fluence rate. The effects of the fixture positions, the numbers of operating UR-UVGI fixture and the spatial volume average fluence rate were examined with different ventilation rates and the susceptibility of airborne microorganism. The simulation was also validated by the experiment. The results showed that the positions of UR-UVGI fixture near the outlet achieved the best disinfection efficiency. Uniform fluence rate produced by the multiple UR-UVGI fixtures system obtained better disinfection efficiency in comparison to the non-uniform fluence rate. In a ventilated room, if the susceptibility of airborne microorganisms >0.2 m2/J, the optimum spatial volume average fluence rate should be 0.45–0.6 W/m2 for a well-designed UR-UVGI system.
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Source:Building and Environment, Volume 103
Author(s): Yi Yang, Alvin C.K. Lai, Chunliang Wu
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