In Heating Ventilating and Air Conditioning (HVAC) systems, ventilation strategies impact building energy consumption, occupants' thermal comfort and Indoor Air Quality (IAQ). Ventilation strategies such as Mixing Jet Ventilation (MJV), Displacement Ventilation (DV), and Impinging Jet Ventilation (IJV) are operated on the different principals. MJV relies on dilution, while DV and IJV rely on both dilution and stratification. Due to climatic variation, ventilation strategies must be operated under different cooling and heating load scenarios. Typically, each ventilation strategy controls the indoor environment through a single adequate flow rate with suitable supply parameters such as temperature, pollutant concentration, vapor, velocity, etc. Hence, the indoor thermal and IAQ condition are independently impacted. A room with excellent thermal condition is possible to have poor IAQ. Given this limitation, vast air flow variables, and occupants' activities, the performances evaluation of these strategies are complicated. In this study, three ventilation strategies, MJV, DV, and IJV are thoroughly investigated. The Computational Fluid Dynamics (CFD) simulation was mainly utilized to handle the complexity of this study. The parametric studies of 48 CFD simulations are presented. Referring to ASHRAE RP-1133, the experimental data from a specially built HVAC-IEQ laboratory was used to validate the CFD data. The research results indicate both advantages and disadvantages in all three strategies. In addition, there is no single strategy that can perform excellently in all indexes. Using the well-known index called ventilation effectiveness (VEF), DV performs outstandingly. However, under a newly proposed index called ventilation performances, DV fails because the stratification discomfort exceeds 36% of room area. MJV suffers from low VEF and excessive draft. However, the IAQ of MJV is not as poor as expected. IJV can be an alternative especially for space where sleeping and sitting activities dominate. IJV can conserve HVAC energy, while maintaining good IAQ. Compared to DV, although VEF is lower, stratification discomfort is minimized to 24%–12% (depending on supply velocity). Overall, this study demonstrates that ventilation strategies are the key to enhance IAQ. Therefore, the utilization of an appropriate ventilation strategy might increase, Leadership in Energy and Environmental Design (LEED) score, particularly for Indoor Environmental Quality, Innovation and Design Process, and Energy and Atmospheric categories.

This research aims at studying the solution for reducing energy consumption of an office building facade with self-shading applications. The four important design variables include orientations, extension self-shading length, Window to Wall Ratio (WWR) and automatic daylight dimmer. Using the simulation program called eQUEST-3.64. This study focuses on self-shading of facade with both single and multiple orientations with 4 variables including shading length, orientations, daylight dimmer, and applications comparison. For the shading length, the research results show that length of a self-shading facade affected the energy reduction most. Self-shading of 2.5 m can achieve the highest energy saving of wide WWR range from 20% - 100%. Also, the most feasible orientation of the self-shading facade is the east, while the north is not suitable for self-shading application. For the daylight dimmer, it can reduce the energy consumption by up to 12% when WWR is optimized. When comparing the self-shading with other applications including shading device and tilted wall, it is found that the self-shading at WWR 20% - 80% is the most efficient solution. Moreover, the energy saving extends greater if using self-shading facade is applied for multiple orientations. The results from this research are useful for architects who are interested in the facade design, and can effectively use self-shading facade to maximize energy conservation benefit.

Intense solar radiation is one of the key design problems for buildings in tropical regions. The recommended practice is to install shading devices, particularly to protect glazing systems. However, many design factors do not allow shading devices to be implemented in all cases; shading devices may not be appropriate to particular design concepts. To serve the designers' preference, alternative solutions should be provided. This study aims at investigating the performance of a new design alternative—the tilted façade. By simply tilting a wall downward, solar radiation can be minimized in the same way as a shading device. The state-of-the-art energy software, eQUEST, was used to simulate energy performance of buildings in Bangkok, Thailand. At the same time, simulated results were confirmed by using experimental data monitoring from specially customized test cells. A wide range of WWR (Window to Wall Ratio) was tested against different façade orientations, glazing types, and shading devices with similar projected lengths. Tilted façades can be most effective for all orientations except for the north. Also, tilted façades allow designers to use more glass without any additional energy consumption. Based on these results, a set of design guidelines for using tilted facades are proposed. Designers can not only utilize these guidelines to effectively adjust façade angle but also optimize the glazing size for the best energy performance.

Under current energy and environmental concerns, buildings are targeted as problems required immediatesolutions. Generally, buildings consume plenty of resources, produce unwanted wastes, and sometimes demoteIndoor Environmental Quality (IEQ). Given these negative impacts, Green Building was introduced as ananswer to mitigate the current energy and environmental problems. Architects, engineers, and practitionersquickly adopt this green building idea but the direction was both diversified and unclear. At that time, proclaimedgreen building seems to be just promise lacking of solid evidences. Energy & Environmental rating systemwas initially proposed as a campaign attempting to quantify green buildings. Different measures were takenand then weighted for scoring purposes. Using these scores, green buildings are possible to be quantifiedand ranked afterward. In this review article, not only the rating systems, i.e. BREEAM, Green Star, and GreenGlobe, TEEAM, will be overviewed, but also LEED, the most dominating system in US, will be discussedin detail. The simplicity by having six sustainability measures including sustainable site, water efficiency,energy and atmosphere, material and resources, IEQ, and innovation in design, are the key success of LEEDrating system. Moreover, the flexibility of having different compliance methods and scoring options makes manydesigners are in favor of this approach. By using performance-base compliance method, designers can comparetheir design against the base case for winning the higher performances such as energy cost. The score willthen be interpolated and given by exceeding performances. In order to obtain high scores, practices andtechnologies that are acknowledged by rating systems, particularly LEED, should be systematically strategized.Xeriscaping, Green Roof, Geothermal Cooling, Displacement Ventilation, and Demand Control Ventilation, arethe examples of such technologies that greatly promote the scores across multiple categories. By reviewingcompositions, mechanism, practice, and technologies of green building rating systems, this article should bea useful source for practitioners who will or already involve in any green building project and looking forwardto quantify their buildings with any rating system in the near future.