Numerical and experimental study of personalized ventilation

Personalized ventilation (PV) is a novel development in the field of heating, ventilation, and air conditioning (HVAC) that has the potential to eliminate the deficiencies of conventional systems. The primary aim of this work is to measure the ventilation effectiveness of PV, to find out the human response to PV, and to develop a numerical thermal manikin (NTM) for the evaluation of the non-uniform thermal environment that is generated by PV. Experimental and numerical studies are reported in this thesis. The work that is presented consists of five parts: (1) a review of PV and computational fluid dynamics (CFD) studies of the thermal environment around a human body, (2) an experimental study of the ventilation seat type of PV, (3) the development of an NTM and its application to investigate the micro-environment that surrounds a human body and the performance of the ventilation seat, (4) the coupling of CFD and an inner-body thermoregulation model to predict local thermal sensation and comfort in the non-uniform thermal environments that are created by three different PV systems, and (5) a comparison of PV performance in a displacement ventilated room and a mixing ventilated room and a discussion of some significant issues of PV.; Experiments using tracer gas and a heated, breathing thermal manikin with an artificial lung find that at an operating ventilation rate of 2.5 l/s, the pollutant exposure reduction effectiveness (PER) of a chair-based PV system can reach about 76%. Subjective measurements reveal that people are found to be more sensitive to the flow rate of personalized air than to its temperature. To enrich thermal comfort theory, it is highlighted that the perceived air quality is significantly affected by the velocity of air on the face. The performance of PV in displacement ventilation and mixing ventilation systems is modeled and compared. In general, it is found that the combination of PV systems with displacement ventilation systems provides better indoor air quality and more opportunities for energy saving than the combination of PV with mixing ventilation systems.