Experimental investigation of difference in indoor environment using impinging jet ventilation and displacement ventilation systems

The impinging jet ventilation (IJV) system has been proposed as a new air distribution strategy and is expected to overcome the disadvantages of mixing ventilation (MV) system, which is the most widely used system, and displacement ventilation (DV), which provides better air quality than MV. The aim of this study is to accumulate the fundamental feature of IJV and to propose a simple method to predict the indoor environment with IJV. Full-scale experiments were conducted in a climate chamber, in order to investigate the features of IJV. Different ventilation systems and supply air conditions were investigated along with indoor thermal environments, and ventilation effectiveness. For IJV, the indoor environment was similar to that of DV with small supply momentum, and was similar to that of MV with large supply momentum. The specific Archimedes number, which can be calculated by design conditions, was defined to express the balance between the supply momentum and buoyancy force. The correlation between the Archimedes number and indices for thermal environment and ventilation effectiveness are finally shown as prediction method.