16 Interaction of Dynamic Indoor Environment with Moving Person and Performance of Ceiling Mounted Personalized Ventilation System
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Ceiling mounted personalized ventilation (PV) aims to provide clean outdoor air into human breathing zone without affecting indoor aesthetics in energy efficient manner. In steady state, its performance depends much on the ceiling mounted air terminal device (ATD) because supply air momentum, other than human body thermal plume and ambient air flow, is the major driving force in the micro-environment of occupied zone. In dynamic indoor environment, the movement of a person near PV ATD causes entrainment or detrainment effect, which can be regarded as another comparable factor influencing ceiling mounted PV performance. A typical office workplace consisting of ceiling mounted PV ATD and ambient air supply diffusers is simulated. One person is seated and another moving person is simulated by dynamic meshes in computational fluid dynamics (CFD). Simulations at moving person velocities of 0.5, 1 and 1,5 m/s and distance between seated person and moving person of 0, 0.2, 0.4 m are performed. A new index, computational personal exposure effectiveness (PEEc), is utilized to assess the performance of ceiling mounted PV system in regard to inhaled air quality under the influence of moving person. Meanwhile, the influence of evenly distributed ceiling mounted PV ATDs on inhaled air quality is also studied. According to numerical results, the stability of ceiling mounted PV under dynamic environment with moving person is acceptable with minor changes of PEEc and inhaled air quality can be improved over larger occupied area for both seated person and moving person.