| To enhance thermal comfort and Indoor Air Quality (IAQ) by using least amount of energy is a challenge for building ventilation system. One answer to this challenge is "ventilation strategies" which are characterized by the placement of the terminal configurations and the control schemes such as supply temperature and velocity. Mixing (MJV), displacement (DV), and newly introduced impinging jet (IJV) system, are the available options for a common ventilated room. Past studies show that IJV performs impressively yet this system is still lacking of studies in many aspects. For the practitioners to use this system, impinging jet characteristics, terminal configurations, operation method such as Variable-Air-Volume (VAV) and Constant-Air-Volume (CAV), and space volume, are four objectives that must be answered with the first priority. In the process of completing these objectives, this dissertation has maximized the use of Computational Fluid Dynamics (CFD) by not only for visualizing the flow but also for developing a new ventilation index called CFD ventilation performances. This index is unique for CFD and impossible to be obtained from full scale experiment. Recommended by the standards such as ASHRAE RP-1133, full scale experiment was rather used for validating the CFD results such as predictive models of an impinging jet. After implementing this newly developed index, well-known indices such as ventilation effectiveness and PMV-PPD (Predicted-Mean-Vote and Predicted-Percentage-of-Dissatisfaction) with related ventilation theories, parameters to make IJV provided the better IAQ and consumed less energy are the results. With high ventilation effectiveness at least 1.1, IJV still can be supplied with normal velocity and typical cool temperature which is not possible for DV, while disadvantages are stratification discomfort and draft near supply terminals. Given the confirmed promising results of a case study classroom, there are many architectural applications possible for implementing IJV. Laboratories, passenger terminals, operating, tunnels, atrium, etc, are all good candidates that come with different settings and requirements. The configurations of IJV in these applications combining with many unknown impacts from furniture lay-out, people movement, transient simulation, etc, raises the demands of not only IJV future studies but also improving the advanced research tools such as CFD. |
