DEVELOPMENT OF THE SWIRLING INDUCTION TYPE DISPLACEMENT HVAC SYSTEM FOR LARGE ENCLOSURES

The ordinary displacement ventilation system (DV) needs large installation spaces for large supplydiffusers with lower supply air velocity to avoid the draft discomfort at the foot level, and large supply airvolume to control allowable vertical temperature gradient within the occupied zone. Furthermore, theDV is difficult to heat without other warming means in the winter. The swirling induction type HVACsystem (SWIT) was developed as utilizing a compact air diffuser increasing the induction function bymeans of swirling air jets. Features of the SWIT are to increase the induction effect on the surface ofSWIT air diffusers, to reduce the supply air velocity, to circulate air in the occupied zone at cooling inthe summer, and to induce cold air mass from the occupied zone with low velocity at heating in thewinter. This paper was summarized measurement results of ventilation effectiveness and temperaturedistribution in the summer and the winter, and compared with an ordinary displacement system andmixing system. Furthermore, we estimated energy conservation of the SWIT by comparing with themixing system for an industrial plant on a scale of 20,000 m2.