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Öğe Numerical and experimental investigation of solar chimney power plant system performance(Taylor & Francis, 2020-03-15) Karakaya, Hakan; Durmuş, Aydın; Avcı, Ali SerkanA prototype of a solar chimney power plant was performed by modeling in this study. The performed prototype was experimentally confirmed. Temperature, velocity, and radiation values were measured to actualize the confirmation. Experimental data that were obtained to determine the performance of solar chimney whose prototype was actualized by the help of measured values were computationally analyzed. The geometry of a solar chimney in the analysis was bidimensionally (2D) drawn on an axis of symmetry. The numerical simulation was analyzed with computational fluid dynamics (CFD) method. Since analysis results show that there is turbulent flow in system (RNG), k-ɛ turbulence model was used. Continuity, momentum, and energy equations were applied to the solar chimney system via the finite volume method. Moreover, DO (discrete ordinates) model was inserted in analysis to evaluate the radiation effect in the collector area. In addition to all these, correlation results between SPSS 17 statistics program and data obtained were evaluated. Finally, with reference to the comparison between numerical and experimental results, data obtained and numerical data are close to each other; the prototype is applicable to the real systems.Öğe Empirical modeling between degree days and optimum insulation thickness for external wall(Taylor & Francis, 2020-03) Karakaya, Hakan; Kallioğlu, Mehmet Ali; Ercan, Umut; Avcı, Ali Serkan; Fidan, CihatInsulating is the most effective method that is used to save energy in buildings. Samples from cities from different climatic zones from TS 825 (Turkey) first. Optimum insulation thickness () analysis is based on two types of insulating and four different fuels (natural gas, coal, fuel oil and electric) of related cities. Cost accounts, payback period and CO2-SO2 emission calculations were performed based on these analyses. Second of all, the relationship between a number of degree day (NDD) and optimum insulation thickness () was developed by linear, quadratic and cubic correlations. Thirty different mathematical correlations based on different fuel types by using XPS and EPS insulating materials. Twenty-four of these models that were developed were generated peculiar to the fuel type; six of them were generated based on average insulation thickness. R2 values of related correlations are between 0.9989 most and 0.9952 at least as well as it is pretty close to (R ≤ 1) one value. The model among these models is the cubic mathematical model that gives the best average value. a = 0.0036, b = 5E-05, c = – 7E-09 and d = 6E-13 are the values for XPS material. Following values are for EPS material; a = 0.0028, b = 5E-13, c = – 7E-09 and d = 4E-05. R2 determination coefficient of both two equations is pretty close to 0.9989 and 1; the models obtained are less-than-stellar. Optimum insulation thickness of the area can be known based on the type of material via the number of degree day without the need for long analyses. According to the R2 values, the use of all models is recommended for academic and industrial users.
