Publication Date

2007-01-01

Availability

Open access

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Civil, Architectural and Environmental Engineering (Engineering)

Date of Defense

2007-02-26

First Committee Member

Xudong Yang - Committee Chair

Second Committee Member

Helena Solo-Gabriele - Committee Member

Third Committee Member

Gecheng Zha - Committee Member

Abstract

This research aims at evaluating a new ventilation concept: personal displacement ventilation (PDV) for improving indoor air quality. The new ventilation method combines room displacement ventilation with task ventilation, the latter being directed at controlling air quality and comfort in the microenvironment where the building occupant is working, with the premise that such directed ventilation will maintain air quality where it matters. This approach could lead to improved ventilation system design that could even provide individual control of indoor microclimate. The effectiveness of PDV was studied by using computational fluid dynamics (CFD) modeling and rigorous validation experiments. First, a small office setup was built in a controlled environmental chamber. Three PDV cases with different locations of contaminant source and one general displacement ventilation (DV) case were investigated. Spatial distributions of airflow, temperature, and hypothetical pollutant distributions were measured. The measured data were then used to evaluate the performance of PDV against defined indoor air quality and thermal comfort criteria, and to validate the CFD model. The validated CFD program was further used to study PDV under various conditions. This study found that basic equipped PDV acts no different from DV from airflow pattern?s point of view. Due to the lack of heat generation around occupant?s legs, local buoyancy effect is not strong enough to attract supply air, which is generated from diffuser nearby, to join in the plume around occupant. However, auxiliary activities adjusting the direction of supply air and adding high panels around person can improve the fraction of supply air to join the plume around person or decrease the average contaminant concentration in breathing zone.

Keywords

Ventilation Bypass Factor; Local Average Concentration

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