|Kwan, Ho-sum Chris
|The application of air purification system in an air-conditioned space
|Hong Kong Polytechnic University -- Dissertations
Air -- Purification
|Department of Building Services Engineering
|xv, 178 leaves : ill. (some col.) ; 30 cm
|This dissertation describes the development of application protocol of air purifier in an air-conditioned space using empirical and modeling techniques. The protocol involves three major steps: pollutant removal rate (PRR) calculation in chamber experiment, equivalent PRR development using computational fluid dynamic (CFD) program and prediction of PRR in University Optometry Clinic. The air purifier was first tested in an environmental chamber to determine the pollutant removal rate. The contaminant's emission was generated by a pulse injection of tracer gas, sulhur hexafluoride (SF6). The concentration of contaminants in the chamber was simulated using Re-Normalization Group k-E model and was compared with the measurement results. 60% of the equivalent PRR factor was determined for the formulation of the PRR prediction model. The air purifier was then installed in the University Optometry Clinic for verification of the predicted results. General observation revealed that the predicted pollutant removal rate (m'cfd) and measured results were in reasonable correlation, with the percentage difference ranging between -8.9% and -18.5%. Both the predicted PRR and the measurement results were found inversely proportional to the distance away from the air purifier. The location of the air purifier influenced the contaminant distribution and hence the average PRR in space. The simulation results also indicated that the contaminant's dispersion pattern was highly dependent on the velocity flow field In this study, a series of total bacteria count and TVOC removal performance experiments were conducted in the University Optometry Clinic to examine the effectiveness of the air purifier. It concluded that the combination of photocatalytic oxidation and UVGI in the air purifier could reduce the decay rate of indoor bacteria count as well as the TVOC concentration. The improvement on reducing bacteria count was more significant under high occupancy conditions and the results also indicated that the bacteria concentration varies with the number of occupants. Furthermore, the significance of adopting titanium dioxide filter only on TVOC removal performance tests was studied in the environmental chamber. The overall effectiveness of air purifier could be enhanced if a titanium dioxide filter was installed. The clean air delivery rate (CADR) equivalent to titanium dioxide dominated over 70% of the overall removal performance of the air purifier.
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