Architecture / Mimarlık
Permanent URI for this collectionhttps://hdl.handle.net/11147/24
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Article 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: 12Citation - Scopus: 12An Evaluation Methodology Proposal for Building Envelopes Containing Phase Change Materials: the Case of a Flat Roof in Turkey’s Climate Zones(Taylor and Francis Ltd., 2017) Tokuç, Ayça; Yesügey, Sadık Cengiz; Başaran, TahsinPhase change materials (PCMs) can be used to enhance the thermal energy storage capacity of a building element to improve indoor thermal comfort conditions and decrease energy usage, yet these effects need to be carefully analysed to achieve the desired benefits. This paper proposes an evaluation methodology for building envelopes: first, a numerical computational fluid dynamics model is validated by experimental work; then, time-dependent simulations are used to analyse monthly energy requirements and heat flux. A sample flat roof is evaluated in terms of required cooling load with and without PCM in Turkey’s climate zones. Graphical phase change representations and heat flux results were used to evaluate the cooling load reduction in addition to the effects of PCM type and PCM amount and the necessity for night cooling. In conclusion, the methodology is flexible and can be utilized to evaluate the building element for various parameters.Article Citation - WoS: 18Citation - Scopus: 21Experimental and Numerical Investigation of Forced Convection in a Double Skin Façade(MDPI Multidisciplinary Digital Publishing Institute, 2017) İnan, Tuğba; Başaran, Tahsin; Erek, AytunçFlow and heat transfer of the air cavity between two glass façades designed in the box window type of double skin façade (DSF) was evaluated in a test room which was set up for measurements in the laboratory environment and analyzed under different working conditions by using a computational fluid dynamics tool. Using data from the experimental studies, the verification of the numerical studies was conducted and the air flow and heat transfer in the cavity between the two glass façades were examined numerically in detail. The depth to height of the cavity, the aspect ratio, was changed between 0.10 and 0.16, and was studied for three different flow velocities. Reynolds and average Nusselt numbers ranging from 28,000 to 56,500 and 134 to 272, respectively, were calculated and a non-dimensional correlation between Reynolds and Nusselt numbers was constructed to evaluate the heat transfer from the cavity (except inlet and outlet sections) air to the inside environment and it could be used the box window type of DSF applications having relatively short cavities.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: 23Citation - Scopus: 25Analysing Visual Pattern of Skin Temperature During Submaximal and Maximal Exercises(Elsevier Ltd., 2016) Balcı, Görkem Aybars; Başaran, Tahsin; Çolakoğlu, MuzafferAims of this study were to examine our hypotheses assuming that (a) skin temperature patterns would differ between submaximal exercise (SE) and graded maximal exercise test (GXT) and (b) thermal kinetics of Tskin occurring in SE and GXT might be similar in a homogenous cohort. Core temperature (Tcore) also observed in order to evaluate thermoregulatory responses to SE and GXT. Eleven moderately to well-trained male athletes were 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 1.93 ± 0.1 m2; body fat: 12.6% ± 4.2%; V̇O2 max: 54 ± 9.9 mL min-1 kg-1). Under stabilized environmental conditions in climatic chamber, GXT to volitional exhaustion and 20-min SE at 60% of VO2 max were performed on cycle ergometer. Thermal analyses were conducted in 2-min intervals throughout exercise tests. Tskin was monitored by a thermal camera, while Tcore was recorded via an ingestible telemetric temperature sensor. Thermal kinetic analyses showed that Tskin gradually decreased till the 7.58 ± 1.03th minutes, and then initiated to increase till the end of SE (Rsqr = 0.97), while Tskin gradually decreased throughout the GXT (Rsqr = 0.89). Decrease in the level of Tskin during the GXT was significantly below from the SE [F (4, 40) = 2.67, p = 0.07, ηp 2 = 0.211]. In the meantime, Tcore continuously increased throughout the SE and GXT (p < 0.05). Both GXT and SE were terminated at very close final Tcore values (37.8 ± 0.3 °C and 38.0 ± 0.3 °C, respectively; p > 0.05). However, total heat energies were calculated as 261.5 kJ/m2 and 416 kJ/m2 for GXT and SE, respectively (p < 0.05). Thus, it seems that SE may be more advantageous than GXT in thermoregulation. In conclusion, Tcore gradually increased throughout maximal and submaximal exercises as expected. Tskin curves patterns found to be associated amongst participants at both GXT and SE. Therefore, Tskin kinetics may ensure an important data for monitoring thermoregulation in exercise.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.Article Citation - WoS: 23Citation - Scopus: 28Thermal Analysis of the Domed Vernacular Houses of Harran, Turkey(SAGE Publications Inc., 2011) Başaran, TahsinMinimum energy consumption and economic efficiency using local and recyclable materials is essential for achieving sustainability, considering the depletion of global energy sources. The Anatolian Peninsula presents a diverse range of local building construction techniques accumulated over centuries, which meet the criteria mentioned above. Due to richness of climatic variety and the influence of many civilisations throughout history, Anatolian regions reflect this richness in their respective solutions to building construction. Built mainly out of brick and stone, mortared and plastered by mud, the domed vernacular houses of Harran, a small town in the province of Urfa in the hot arid climate of southeastern Anatolia, are one of the best examples that deserve attention with respect to minimum energy consumption. In this study, the thermal performance of the "Harran house" as a vernacular type was analysed. For this purpose, temperatures inside and outside a Harran house complex with relative humidity variations were measured. In addition, for investigating the domed houses' thermal behaviour, temperature measurements at different surfaces and media were recorded. The solar chimney effect obtained from the dome and the importance of the thermal mass of the square base of the house were also evaluated. The study yielded results, which showed that the indoor conditions were within the limits for thermal comfort even under extreme summer conditions.