Browsing by Author "Uckan, Irfan"

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Development of an Artificial Neural Network Model for the Prediction of the Performance of a Silica-Gel Desiccant Wheel
(Taylor & Francis inc, 2015) Uckan, Irfan; Yilmaz, Tuncay; Hurdogan, Ertac; Buyukalaca, Orhan
This work presents mathematical equations derived from Artificial Neural Networks (ANNs) for the estimation of dry bulb temperature and specific humidity at the outlet of a desiccant wheel to predict useful data for designers and engineers. The neural network model comprises five inputs and two output neurons that define the outlet conditions (dry bulb temperature and specific humidity) of a desiccant wheel. The results obtained by the ANN model are compared with the actual data by using input variables. The results show that the mean absolute percentage errors for dry bulb temperature and specific humidity are found to be 0.80% and 1.56% respectively; and the correlation coefficient (R) values obtained are approximately 0.986 for both output variables. The root mean square errors, which is another significant point in this study, are found to be 0.54% and 0.18% for dry bulb temperature and specific humidity respectively.
Effect of Operation Conditions on the Second Law Analysis of a Desiccant Cooling System
(Pergamon-elsevier Science Ltd, 2017) Uckan, Irfan; Yilmaz, Tuncay; Buyukalaca, Orhan
In order to evaluate the potential of a desiccant based evaporative air conditioning system, a second law analysis of the systems was investigated. In this work, a wide range of working parameters that are regeneration temperature from 90 degrees C to 110 degrees C, volume flow rate from 2000 m(3) to 4000 m(3) and ambient air conditions which are relative humidity, ambient air temperature and wet-bulb temperature is carried out for performance calculation of the system. It is observed from results that the Carnot COP and the thermal COP of the system varies vice versa during the day. The highest value of Camot COP and the thermal COP is about 25 and 0.62, respectively. Also, the cooling capacity has significant effect on the second law efficiency. The importance of this study shows that the second law analysis can provide useful information with respect to the theoretical upper limit of the system performance, which cannot be obtained from the first law of thermodynamic analysis alone. (C) 2016 Elsevier Ltd. All rights reserved.
Estimation and Comparison of Various Global Solar Radiation Models on Horizontal Surface in a Hot and Dry Region
(Taylor & Francis inc, 2018) Uckan, Irfan; Khudhur, Kameran M.
In this study, 54 empirical models including 22 new models were used to estimate the global solar radiation on horizontal surface. The data were collected in Dohuk cities in the northern Iraq. The evaluated models are based on sunshine duration, air temperature, cloud cover, and other meteorological parameters. In the investigated region, the statistical error indicators value for all empirical models of R, R-2, mean absolute bias error, root mean square error, mean absolute percentage error, Nash-Sutcliffe equation, and t-test value were low and within an acceptable range. The results of Model 49 based on the other meteorological parameters which is newly developed model with equation H/H = H a+b in triangle T+C(T-min /T-max) + dRH had the most appropriate result with a value of R-2 (0.9942) in the 54 empirical models. Besides, 22 new equation models are produced based on sunshine hours, air temperature, and other meteorological parameters. The best accuracy among the new equation was observed in Model 49. Furthermore, the Models 34, 12, and 25 based on cloud cover, sunshine hour, and air temperature in terms of data accuracy were ranked, respectively.
Exergy Analysis of a Novel Configuration of Desiccant Based Evaporative Air Conditioning System
(Pergamon-elsevier Science Ltd, 2014) Uckan, Irfan; Yilmaz, Tuncay; Hurdogan, Ertac; Buyukalaca, Orhan
In this work, a process is developed for exergy analyses of a novel configuration of desiccant based an evaporative air conditioning system. The exergy transfer and destruction between the components of the system are defined for the average measured variables obtained from the experimental results. The exergy formulations are carried out to the experimental system using the data collected during a typical operation of the system. The exergy output, specific flow exergy, exergy destruction, exergy input and exergy efficiency are determined. Furthermore, the sustainability assessment and relative irreversibility of components are obtained. It is found that the exergy efficiency of the entire experimental unit is 40.7% at a reference temperature of 15 degrees C. It is also observed that the exergy efficiencies of the entire system varies between 56% and 25% for reference temperature of 0-30 degrees C, respectively. The effects of reference temperature on the performance of the studied system are investigated. Based on the investigation, it is seen that an exergy analysis can provide beneficial knowledge with respect to the theoretical upper limit of the system performance. (C) 2014 Elsevier Ltd. All rights reserved.
Exergy Analysis of Solar Radiation Based on Long Term for Van City
(Gazi Univ, 2017) Uckan, Irfan
The present study has analyzed the solar radiation exergy for the period of 1993 to 2007 in Van (38.28 degrees N, 43.20 degrees E). In this regard, various models have been applied for determination of solar radiation exergy. The exergy efficiency of solar radiation taken from meteorological data is evaluated based on these models for Van. According to results, the highest long term monthly average solar radiation exergy values is observed in June with 26.85 MJ/m(2) for Petela Model and same result also is observed for Spanner model but Jeter's approach is different from these models approximately % 1.7. The ratio of solar radiation exergy to the long term monthly average solar radiation energy values varies from 0.934 to 0.939 both Spanner and Petela approach, and from 0.950 to 0.954 for Jeter's approach. The highest annual value exergy of the solar radiation is observed for the year of 2000 with 19.68 MJ/m(2) and the lowest annual value exergy of the solar radiation is found for the year of 1993 with 16.50 MJ/m(2).
Experimental Investigation of a Novel Configuration of Desiccant Based Evaporative Air Conditioning System
(Pergamon-elsevier Science Ltd, 2013) Uckan, Irfan; Yilmaz, Tuncay; Hurdogan, Ertac; Buyukalaca, Orhan
A novel configuration of desiccant based evaporative cooling system for air conditioning application is developed and tested. At the beginning of the design stage of the system, an analysis is carried out in order to maximize the performance of the system. It is found based on configuration that outdoor air must be used for regeneration to increase performance of the system and so three air channels are used. Experiments are carried out to investigate the total performance of the system and performance of the components used during summer season in a hot and humid climate. Effectiveness values for both heat exchangers and evaporative coolers are calculated through this work. In addition to the cooling capacity, coefficient of performance (COP) and energy consumption of the system are also evaluated. Results show that the effectiveness for the heat exchangers and evaporative coolers are very high under different outdoor conditions. It is also shown from the results that indoor air conditions are in the range of thermal comfort zone defined by ASHRAE and expanded comfort zone for evaporative air conditioning applications. (C) 2012 Elsevier Ltd. All rights reserved.
Improving of Global Solar Radiation Forecast by Comparing Other Meteorological Parameter Models With Sunshine Duration Models
(Springer Heidelberg, 2022) Uckan, Irfan; Khudhur, Kameran Mohammed
The aim of this study is to compare sunshine duration-based models and the other meteorological parameter-based models and to develop new forecasting models. The estimation and comparison of global solar radiation has been made by using twenty-four empirical models including three new models for different location named Arbil, Dohuk, and Sulaimania of Northern Iraq. The reason of using these different locations is to test the accuracy of the other meteorological parameter models by comparing the sunshine duration models for different region. Mostly common statistical error values are used to evaluate the performance of the estimation models and to identify the models that will give the closest results to the actual values. According to the results, it was seen that the models based on other meteorological parameters have better predictions than the models based on the sunshine duration. While the R-2 value of the best models depending on the sunshine duration ranged from 0.97 to 0.99, the R-2 values of the best models of other meteorological parameters are above 0.99. Furthermore, it is observed that the new proposed models provide better estimates of global solar radiation at different locations than all models used in this study.
Investigation of the Effect of Various Solar Collector Types on a Solar Absorption Cooling System
(Taylor & Francis inc, 2021) Uckan, Irfan; Yousif, Ali Abdullah
A single-effect absorption cooling system was planned and simulated appropriate to a hot and dry climate, and optimization was made accordingly in the present study. TRNSYS software is a very comprehensive program that includes much equipment in its subprograms. For this reason, solar collectors, cooling tower, auxiliary heater, and storage tank used in this study are modeled in this software. The designed cooling system is considered as a market that has a cooling need of 35 kW and has a space of 275 m(2). It was examined in this study that how the performance of a single-effect LiBr-H2O absorption cooling system was affected by three different kinds of solar collectors such as flat plate collector (FPC), Non-tracking concentrating parabolic solar collector (XCPC), and evacuated tube collector (ETC). It was also evaluated that how different criteria such as solar fraction, hot water tank temperature and tank volume, collector area, and collector type affected system performance. In the study, it was noticed that collector area had an important effect on the collector efficiency, heater power and hot water tank temperature. It was found that minimum collector area for XCPC, ETC and FPC collectors were approximately 100 m(2), 125 m(2)and 150 m(2), respectively. Also, depending on the change in the tank volume, significant changes occurred in the tank temperature. The hot water tank volume was raised from 0.5 m(3)to 6 m(3)for XCPC, ETC and FPC collectors, the upper hot water tank temperature decreased about 15 degrees C, 11 degrees C and 8 degrees C, respectively. In conclusion, it has been observed that XCPC collectors perform better to improve system performance compared to other collectors used.
Investigation the Performance of a New Fuel Produced From the Phthalocyanine-Gasoline Mixture in an Internal Combustion Engine
(Pergamon-elsevier Science Ltd, 2024) Uckan, Irfan; Yakin, Ahmet; Cabir, Beyza
The study involved the utilization of novel developed six distinct fuel, denoted as, PG5, PG10, PG15, PG20, PG25, and PG30 and G100 (pure gasoline). These fuels were derived from various blends of gasoline and phthalocyanines. Experimental investigations were conducted to assess the internal combustion engine's performance in terms of both energy and exergy. The mixtures underwent testing across a range of engine speeds, spanning from 1400 rpm to 3000 rpm. Notably, optimal performance across all fuels and engine speeds was consistently observed at 2600 rpm. In terms of energy and exergy efficiency assessments for all fuels and engine speeds, PG25 fuel demonstrated the highest efficiency levels, with 35% energy efficiency and 33% exergy efficiency at 2600 rpm. Conversely, G100 fuel exhibited the lowest energy and exergy efficiency at the same engine speed, registering values of 27% and 24%, respectively. Meanwhile, with regard to exhaust exergy, G100 fuel demonstrated the highest exhaust energy at 10.69 kW, occurring at 3000 rpm, whereas PG25 fuel exhibited the lowest exhaust exergy, measured at 3.09 kW. It has been observed that N2 gas, one of the exhaust components that affects the exergy of exhaust gases, affects the exhaust exergy to a large extent and this ratio is approximately 50%. In addition, the sustainability index value for all fuels was found to be at most 2600 rpm. It was calculated as 1.50 for PG25 fuel and 1.32 for G100 fuel.
Second Law Analysis of an Internal Combustion Engine for Different Fuels Consisting of Nabh4, Ethanol and Methanol Mixtures
(Pergamon-elsevier Science Ltd, 2024) Uckan, Irfan; Yakin, Ahmet; Behcet, Rasim
This study was carried out to investigate the effects of NaBH4, which is not used as an internal combustion engine fuel in the literature, on system energy and exergy when used in internal combustion engines. In the study, fuels containing oxygen and hydrogen (MSG12.5, EG12.5, ESG12.5 and MG12.5) and pure gasoline (G100) were tested at different engine speeds and the changes in the energy and exergy analyzes of the system were inves-tigated. In the experimental study, the energy and exergy values of gasoline used as fuel were at the highest values with 33.21 kW and 35.62 kW, respectively, while the energy and exergy efficiencies were 27 % and 25 %, respectively. MG12.5 fuel used in the study showed the best performance among all fuels with 38 % energy efficiency and 35 % exergy efficiency. On the other hand, it was seen that boron added ESG12.5 % fuel was the second best fuel with 35 % energy efficiency and 33 % exergy efficiency. Another fuel, boron added MSG12.5 fuel, performed better than gasoline in terms of both energy and exergy efficiency. In addition, it was determined that more than 50 % of the exergy of the fuel entering the system was lost due to exergy destruction and the exergy destruction of the fuels used in the experiments was determined at least in MG12.5, ESG12.5, EG12.5 and G100, respectively.