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Cho, Y (2004) Effect of change in work environment locations on ventilation performance, Unpublished PhD Thesis, School of Construction Management and Engineering, University of Reading.

  • Type: Thesis
  • Keywords: jet and plume; indoor air quality; thermal comfort; air distribution index; zonal purging flow rate
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  • Abstract:
    This thesis contributes to numerical and experimental studies on the effect of change in heat source location on ventilation performance in a mixing ventilation system. The assessments are discussed with respect to indoor air quality, thermal comfort and energy saving and are carried out by flow element methods and macro analysis based on numerical simulations. The main emphasis is on the macro analysis which is based on Computational Fluid Dynamics (CFD) simulation. This analysis can provide information relating to air flow, heat transfer, thermal comfort and ventilation in a three dimensional situation. Also, this can supplement the somewhat limited data that has been obtained from the point measurement in ventilated rooms. The temporal effectiveness based on the concept of age of air distribution and the spatial effectiveness based on the zonal purging flow concept are used for indoor air quality and thermal comfort. A new ventilation parameter ADI that combines the decoupled indices for indoor air quality and thermal comfort has been applied in this work. It has been found that this parameter is suitable for comparing the results from different workstation locations. Some influential parameters, with regards to the interaction between jet and plume, on air movement, the ventilation effectiveness and the mean and maximum velocities in the occupied zone are numerically and experimentally studied for a mixing ventilation system. The most influential factors on mean velocity under the same conditions but with different heat source locations are determined using the multiple regression analysis. It was found that the dominant parameter is varied with the change in heat source location. The location to achieve a good ventilation performance and the most suitable work environment for different ventilation systems is considered and discussed. For mixing ventilation, it has found that the optimum object location in a two dimensional parametric room is where the maximum velocity in the occupied zone occurs and the optimum location for heat source is in close proximity to the air outlet in a room.