Haruna Yamasawa

The impinging jet ventilation (IJV) system has been proposed as a new air distribution strategy and is expected to overcome the disadvantages of the mixing ventilation (MV) system, which is the most widely used system, and displacement ventilation (DV), which provides better air quality than MV. This study aims to predict the vertical profile of temperature and contaminant in a room with impinging jet ventilation system (IJV) by a calculation model based on the zonal model and turbulence jet the

Abstract This study aims to acquire an understanding of the fundamental feature of IJV and DV under heating operation. Full‐scale experiments were conducted under these two different systems and supply air conditions along with temperature distribution and ventilation effectiveness. A wall surface of the test room was cooled as a heating load, and heating elements simulating occupants were located as internal heat load and contaminant emission source. Three cases of supply temperature were teste

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

Abstract In the existing ventilation design, the ventilation rate is defined by the time‐averaged flow rate, and the fluctuating (turbulence) component is not typically considered. However, inlet turbulent conditions are also assumed to have some influence on the formation of contaminant distributions. Therefore, the influence of turbulent kinetic energy at the inlet boundary on scalar transportation in an indoor environment needs to be elucidated when discussing the ventilation rate setpoint vi

Using the impinging jet ventilation system (IJV), it is possible to accomplish high ventilation effectiveness by creating temperature and contaminant stratification within the room. Since the air is supplied toward the floor and directly spreads into the occupied zone at the lower level, it is important to understand the flow feature of supplied jet around the floor. To understand this, the velocity profile of the jet over the floor at the central cross-section was measured using hotwire anemome

The impinging jet ventilation system (IJV) is drawing people’s attention due to its high ventilation effectiveness and applicability to various situations. In IJV, the fresh air is supplied downward and moves along the floor until it reaches the heat and contaminant source; finally, it is exhausted around the ceiling. Because of this ventilation strategy, temperature and contaminant concentration profiles stratify vertically, so that the effectiveness of temperature and ventilation is kept high

• The fundamental IJV flow features were first measured under isothermal conditions. • The supply velocity and turbulence intensity were measured to be 2.8 m/s and 9.8%. • The maximum velocity decay and jet half-width expansion were shown as equations. • The jet profiles at different angles can be predicted using these equations. • The listed findings can be applied to both the isothermal and cooling conditions. Using the impinging jet ventilation system (IJV), it is possible to accomplish high