Browsing by Author "Eraslan, Tolga Arda"

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A numerical investigation of thermal comfort with different air diffusers at enclosed office space
Eraslan, Tolga Arda; Mengüç, Mustafa Pınar; Mengüç, Mustafa Pınar; Ertunç, Özgür; Ertürk, H.; Department of Mechanical Engineering
People spend most of their time in indoor environments, which highlights the significance of heating, ventilation, and air conditioning (HVAC) systems in these spaces. While ensuring the comfort of occupants in indoor spaces, it is also essential to maintain the efficient operation of these systems. Studies related to this topic are ongoing in the present day. HVAC should not only be seen as individual devices within it, but rather as a whole system. By doing so, the efficiency of each component can be enhanced. HVAC systems consist of various components, including heating and cooling units, ventilation units, dampers, air terminals, louvers, ducts, and pipes, among others. One of the most crucial elements that interact with the indoor environment is the air terminal. In this thesis, the interaction of air terminals with occupants in indoor spaces was observed and visualized using Computational Fluid Dynamics (CFD). Three types of diffusers were used in the study: square diffuser, four-way swirl diffuser, and a hexagonal diffuser designed by Cem Keskin. The interaction of these diffusers with the air inside the room, their airflow characteristics, and their impact on thermal comfort were investigated. The Fanger method's six variables were discussed in this context. Based on the findings, it was observed that the airflow characteristics of the hexagonal diffuser varied based on the openings, while the four-way swirl diffuser was found unsuitable for providing thermal comfort in an office environment. Additionally, when aiming for even air distribution, there is no energy difference among the diffusers. However, if only a specific area require conditioning, it's noticeable that the hexagonal diffuser consumes less energy compared to the other types of diffusers.
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Airflow characteristics and thermal comfort of air diffusers
(ASME, 2023) Eraslan, Tolga Arda; Keskin, Cem; Mengüç, Mustafa Pınar; Mechanical Engineering; MENGÜÇ, Mustafa Pınar; Eraslan, Tolga Arda; Keskin, Cem
Indoor environment quality control is very important for building operations as occupant of buildings spend up to 90% of their time indoors. After Covid-19 pandemic break out, indoor environment quality has become even more crucial to the society because of health concerns. Indoor Environmental Quality (IEQ) covers conditions such as air quality, lighting, thermal conditions, ergonomics inside a building and their effects on the occupant or occupants of the building. Thermal conditions and air quality are usually achieved with the mechanical or natural ventilation systems or by HVAC equipment. As buildings became more complex structures, different airflow distribution systems to be developed to fulfill such requirements. For this purpose, not only the airflow distribution systems need to be modified but also diffusers that provide which supplies/draws air to/from systems are to be improved. Detailed analysis of these subcomponents is needed to assure that such devices provide high levels of comfort effectiveness and energy efficiency. The objective of this study is to develop a comprehensive analysis for air characterization and indoor air regime of different diffusers (square diffuser, operable flap diffuser) and their effect on comfort level of occupants Fanger’s model of thermal comfort is used with CFD simulations and a tool is considered for the validation experiments. Using more than 16 thermal sensors including one on a mannequin head, on a table and at foot level, the readings were correlated by using anemometers to measure air flow at supply diffuser and at different operating levels. CFD simulations were according to different scenarios which are to provide a comparison between diffusers and understand indoor airflow regimes. The results considering the flow interaction between diffusers and surroundings showed a detailed visual illustration in CFD simulations and their relation to perceived comfort levels.