Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 20Citation - Scopus: 17Optimizing Thermal Comfort in Physical Exercise Spaces: a Study of Spatial and Thermal Factors(Elsevier, 2024) Avcı, Ali Berkay; Balcı, Görkem Aybars; Başaran, TahsinFitness centers have become famous for maintaining a healthy lifestyle. They require different thermal comfort conditions and higher fresh air supply rates than other indoor spaces. However, even well-designed centers may cause discomfort due to factors such as design decisions, ventilation, overheating, and overcrowding. The standards for fitness centers do not consider these specific requirements sufficiently, so this study focuses on understanding the thermal comfort requirements during physical exercise and evaluating spatial and thermal factors affecting the thermal environment around the body. The study investigated the ceiling height, lateral and frontal distances between machines, and vent locations as spatial factors and inlet temperature and air velocity as thermal factors. A thirty-minute moderate-intensity constant work rate exercise test was conducted in a controlled climatic chamber using a cycle ergometer with six healthy male participants. The experiment conditions were simulated in CFD software using the collected data. Once a validated simulation model was provided, computational models for different environmental and spatial scenarios for the five-person cycling class were generated. Using Taguchi L9 (34) orthogonal arrays method, nine spatial scenarios were simulated with three different thermal operations each. Optimal factor levels were determined by using thermal comfort conditions (based on predicted mean vote) around the body's thermal plume. The results showed that a ceiling height of 5 m, lateral and frontal distances of 1 m and 0.5 m between machines, and Type 2 (two inlets mounted on the ceiling) ventilation strategy were optimal for achieving better thermal comfort values in a thermal condition of 18 °C and 0.2 m·s−1. The study found that increasing the ceiling height and using cross-positioned vents that project air vertically from the ceiling improved the comfort conditions significantly. It is expected that these criteria, which were determined, compared with the standards and detailed, will contribute to the production processes of comfortable exercise spaces.Article Citation - WoS: 30Citation - Scopus: 30Thermal Retrofitting for Sustainable Use of Traditional Dwellings in Mediterranean Climate of Southwestern Anatolia(Elsevier, 2022) Timur, Barış Ali; Başaran, Tahsin; İpekoğlu, BaşakThermal retrofitting implementations are crucial for safeguarding the functional sustainability of historical buildings as they can improve the thermal performance of these buildings while maintaining thermal comfort for their occupants. This study aims to examine the thermal behavior of a common historical building type in Anatolia / Turkey, the traditional houses with exterior hall (sofa), and to determine enhancement potentials of possible thermal interventions. Research method consists of on-site thermal measurements, laboratory analyses on traditional construction materials and transient thermal analyses utilizing simulations on DesignBuilder software. Study cases were selected from both urban and rural sub-settlements. The results demonstrated that the thermal insulation works within floor assemblies, airtightness measures, adding secondary glazing to windows and suggesting transparent circulation corridors provide significant energy improvements. These interventions would save 26.5% of building energy consumption in the urban and 30.4% in the rural sub-settlements when applied together. Furthermore, when the integration of a modern HVAC system, ground-source heat pump is implemented, these improvement rates can be increased to more than 60%. Consequently, it was determined that the cases have significant potentials for thermal enhancements which renders the application of thermal interventions as a capable conservation tool.Article Citation - WoS: 23Citation - Scopus: 30Experimental Investigation of a Decentralized Heat Recovery Ventilation System(Elsevier Ltd., 2020) Pekdoğan, Tuğçe; Tokuç, Ayça; Ezan, Mehmet Akif; Başaran, TahsinIndoor air quality is an important issue for improving and maintaining the indoor environment because it is directly related to people's health and work performance. These days, in many settlements, the applicability of natural ventilation is limited in the face of the decreasing infiltration loads, increased atmospheric pollution, and the climatic conditions. Therefore, the use of mechanical systems that are designed to ensure proper ventilation is becoming widespread. This paper presents full-scale experimental research of a wall-integrated decentralized ventilation system with heat recovery in the laboratory conditions. The heat recovery unit includes a ceramic block for sensible thermal energy storage. Parametric experimental studies were carried out to obtain the temperature distributions and the thermal capacity of the ceramic block during the supply and exhaust modes of working. In order to simulate the winter and summer conditions, two large scale temperature-controlled rooms are built up. The duration of the ventilation period is varied to be 1, 2, 5, 7.5 and 10-min. Experimental measurements indicate that 2 min of operation time shows the best thermal performance in terms of maintaining a comfortable indoor temperature with the least energy consumption. And some shortcomings were observed about the fan and thermal storage limitations. © 2020 Elsevier LtdArticle Citation - WoS: 15Citation - Scopus: 19Associations Between Thermal and Physiological Responses of Human Body During Exercise(MDPI, 2017) Başaran, Tahsin; Zora, Süleyman; Balcı, Görkem Aybars; Çolakoğlu, MuzafferIn this study, thermal behaviours of the athletes were investigated with respect to thermal comfort and exercise intensity. The relationship between an index for analysing thermal comfort (Predicted Mean Vote: PMV) and Rating of Perceived Exertion (RPE) which shows exercise intensity and exhaustion level was evaluated. Eleven moderately trained male athletes (V) over dotO(2max) 54 +/- 9.9 mL.min(-1).kg(-1)) had volunteered for the study (age: 22.2 +/- 3.7 years; body mass: 73.8 +/- 6.9 kg; height: 181 +/- 6.3 cm; Body surface area (BSA): 1.93 +/- 0.1 m(2); body fat: 12.6% +/- 4.2%; (V) over dotO(2max): 54 +/- 9.9 mL.min(-1).kg(-1)). Experiments were carried out by using a cycle ergometer in an air-conditioned test chamber which provided fresh air and had the ability to control the temperature and relative humidity. The study cohort was divided into two groups according to maximal oxygen consumption levels of the participants. Statistical analyses were conducted with the whole study cohort as well as the two separated groups. There was a moderate correlation between PMV and RPE for whole cohort (r: -0.51). When the whole cohort divided as low and high aerobic power groups, an average correlation coefficient at high oxygen consumption cohort decreased to r: -0.21, while the average correlation coefficient at low oxygen consumption cohort increased to r: -0.77. In conclusion, PMV and RPE have a high correlation in less trained participants, but not in the more trained ones. The case may bring to mind that thermal distribution may be better in high aerobic power group in spite of high RPE and thus the relation between PMV and RPE is affected by exercise performance status.Article Citation - WoS: 40Citation - Scopus: 44Experimental and Numerical Investigation of Forced Convection in a Double Skin Façade by Using Nodal Network Approach for Istanbul(Elsevier Ltd., 2019) İnan, Tuğba; Başaran, TahsinIn this study, temperature distribution and heat transfer through the cavity of a double skin façade (DSF) was investigated in the laboratory environment and analyzed numerically by using nodal network approach. The verification of the nodal network method was conducted by using data from the steady-state experiments and the same method was applied for the climate of Istanbul, Turkey under unsteady outside boundary conditions. Furthermore, heat gain and loss values in DSF for January and July were calculated and compared with single skin façade (SSF) application for different directions of the façades. The results were given for a day and a working time period of the office buildings by using monthly average daily climate data. Distinction working hours were more convenient to investigate the energy performance of DSF because of solar radiation effect. Using DSF in all directions, the cooling loads decreased up to 26% comparing to the SSF. DSF system was disadvantageous comparing to the SSF for January. However, it was shown that the heated air in the cavity could be used for preheating process of air in a HVAC system for winter period.Article Citation - WoS: 30Citation - Scopus: 34Thermal Performance of Different Exterior Wall Structures Based on Wall Orientation(Elsevier Ltd., 2017) Pekdoğan, Tuğçe; Başaran, TahsinHeat transfer from opaque walls of buildings is very important for energy saving and providing thermal comfort in different climates. In this study, insulation models of opaque walls with different orientations and external, internal and sandwich materials were numerically analyzed in terms of their time-dependent thermal behaviors. The one-dimensional transient heat conduction equation was solved via the implicit finite difference method for summer and winter conditions and northern, southern, eastern and western orientations. Meteorological data for cities in Turkey with different climates, i.e., Ankara, Erzurum, İstanbul and İzmir, were used in these calculations. When the outside boundary conditions were defined by using January and July monthly averages of the daily data; the inside air temperature was assumed to be 20 °C and 24 °C in winter and summer. The results indicated that sandwich wall insulation produced more convenient heat loss and heat gain for each climate and direction. The standard deviations of the heat transfer values for the different directions were larger in summer than in winter because of the solar radiation effect. The numerical calculations for the sandwich wall applications were carried out for different insulation thicknesses namely 0.15 m and 0.25 m, and for an uninsulated wall; the results were also compared with Turkish directive on the thermal insulation of buildings, TS825 taken as a reference condition. Compared with the insulation thickness calculated based on the TS825, the heat loss and gain values could be decreased by up to 65% and 80% for the worst winter and summer conditions.Article Citation - WoS: 30Citation - Scopus: 32Experimental and Numerical Investigation of Natural Convection in a Double Skin Facade(Elsevier Ltd., 2016) İnan, Tuğba; Başaran, Tahsin; Ezan, Mehmet AkifIn this study, airflow and heat transfer in a rectangular cavity that simulates a double skin facade and includes natural convection were examined numerically and experimentally. This cavity separates the exterior space and the thermally controlled interior space. The temperatures of the surfaces that interact with these spaces were determined experimentally, while the other surfaces were regarded as adiabatic. With these temperature values, the parameters of the numerical study were defined. After the validation of the numerical model was completed based on experimental studies in the literature, the results related to flow and heat transfer in the cavity were analyzed. The numerical model provided results that agree with the air temperature values found experimentally in the cavity. Accordingly, in natural convection, with Rayleigh numbers ranging from 8.59 ∗ 109 to 1.41 ∗ 1010 and the effect of buoyancy on the regions close to the surface, the increasing tendency of the average Nusselt number from 142.6 to 168.8 was shown. In addition, a correlation between the Rayleigh and Nusselt numbers for a cavity aspect ratio of 8.64 was constructed to evaluate the heat flux; this correlation was also shown graphically.Article Citation - WoS: 54Citation - Scopus: 63An Experimental and Numerical Investigation on the Use of Phase Change Materials in Building Elements: the Case of a Flat Roof in Istanbul(Elsevier Ltd., 2015) Tokuç, Ayça; Başaran, Tahsin; Yesügey, Sadık CengizThis paper reports on the experimental and numerical analysis of a building element-a flat roof-that incorporates phase change material (PCM) as a layer. First, a planar model of the building element of 50 cm by 50 cm surface area was constructed in laboratory conditions to be used in the experimental work. During the experiment, changes in the thermal balance were investigated by temperature and volumetric flow rate measurements, as well as observation of the phase change interface. Next, the experimental measurements were used to validate a numerical computer fluid dynamics (CFD) model for simulation purposes. The model is one-dimensional and is based on the first law of thermodynamics. Finally, a time-dependent simulation for summer conditions was performed using the climatic data of Istanbul. The thickness of the PCM inside the roof element was investigated accordingly. The simulation data showed the solid/liquid phase of PCM over time. Monthly graphs were drawn for ease of comparison of the use of PCM with thicknesses varying between 1 and 5 cm. Consequently, a PCM thickness of 2 cm was found to be suitable for use in flat roofs in Istanbul.Article Citation - WoS: 17Citation - Scopus: 19Experimental Investigation of the Pressure Loss Through a Double Skin Facade by Using Perforated Plates(Elsevier Ltd., 2016) Başaran, Tahsin; İnan, TuğbaThe aim of this study is to analyze the effect of perforated elements on pressure drop in a double skin facade cavity. This cavity separates the exterior and interior space as thermally controllable. The temperatures of the surfaces facing cavity with exterior and interior spaces have been determined experimentally under different airflow conditions. Two distinct perforated plates having different circular hole dimensions are positioned in the double skin facade cavity in order to create a pressure drop in the cavity. Pressure drops and temperature distributions in the cavity have been examined based on experimental measurements. The results show the surface and air temperature distributions in the cavity, the pressure drops under three different air flow rates and two different perforated plates. The dependence of the dimensionless pressure drop coefficient, Euler versus Reynolds numbers is investigated experimentally for different geometric characteristic of the perforated plates. So, Eu numbers independency after 30,000 of the Re numbers approximately is shown graphically. Evaluating the pressure loss in the DSF's cavity under usage of different type of pressure drop elements is essential for ventilating the cavity and choosing the fan capacity in the DSF applications.