CFD Analysis of Airflow Characteristics inside Office Room with Hybrid Air Conditioning-System

The hybrid air-conditioning system is consistsof natural ventilation and mechanicalair-conditioning system in this paper. Theairflow characteristics inside office room withdifferent way to introduce the natural ventilationwere analyzed by means of CFD analysis. Theoffice has the same air-conditioning system byUnder Flow Air Distribution (UFAD). Threeways to introduce the natural ventilation wereused in the analyses. Outdoor air is introducedinto office room from Outdoor Air Intake (OAI)on ceiling, outward wall upper window, andfloor. Conceptual diagrams of analyzed modelwere shown in Figure 1. The airflowcharacteristics of office room were examined bythe distribution of temperature and Scale forVentilation Efficiency No. 4(SVE4, Murakamiand Kato, 1992) that presents the contributionratio of each supply outlet. Influence of way tointroduce natural ventilation on thermal andairflow environment is large. Among models,the Window Model, which fresh outdoor air issupplied from outward wall upper window, hasthe widest zone where a lot of fresh outdoor airwas supplied (the SVE4-n values are larger than0.6).