Sürdürülebilir Kalkınma Amaçları
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- ArticleYalnız künye2023NUMERICAL INVESTIGATION OF A SERPENTINE-TUBE COLD PLATE COOLED LITHIUM-ION BATTERY UNDER WIDE PARAMETRIC CONDITIONS
Kalkan, Orhan; Celen, Ali; Bakirci, Kadir
This paper examines the thermal management of a commercial 20 A h lithium ferro phosphate battery with the cold plates containing the serpentine tube structure, which is frequently preferred in heat exchanger applications. A numerical analysis is performed to explore the battery surface temperature distribution under varying operating conditions. In the study, an experimentally verified electrochemical thermal compound model was created and temperature distributions at the end of discharge at 1C, 3C, and 5C rates are obtained. The effects of different inlet temperatures (15°C, 25°C, and 35°C) and volumetric flow rates (0.1 L/min, 0.6 L/min, and 1.1 L/min) of the coolant on the two vital parameters of battery thermal management –- maximum battery temperature and maximum battery temperature difference –- are investigated for each discharge rate. As a key finding in this study, there is an acceleration of temperature variation from the middle part of the battery with the minimum temperature to the terminals with the maximum temperature, at the end of the discharge, in the use of a serpentine cold plate. Under the conditions where the coolant flow rate is maximum and the inlet temperature is minimum, the highest maximum temperature difference is 14.4°C, while the lowest maximum temperature difference is 10.8°C under the conditions where the coolant flow rate is minimum and the inlet temperature is maximum. Besides, the correlation equations in which the adjusted R2 values for maximum battery temperature difference and maximum battery temperature are 98.0% and 99.6%, respectively, are developed.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2022Prediction of experimental thermal performance of new designed cold plate for electric vehicles’ Li-ion pouch-type battery with artificial neural network
Kalkan, Orhan; Colak, Andac Batur; Celen, Ali; Bakirci, Kadir; Dalkilic, Ahmet Selim
Since liquid-based thermal management systems are usually preferred methods for battery electric vehicles and cold plates are generally preferred to circulate the coolant, studies on their design are becoming increasingly essential. Besides, it seems useful to work artificial intelligence approaches to evaluate different battery thermal management systems, as it is known that the use of artificial intelligence is increasing in many applications today. The aim of this paper is to build up an artificial neural network model due to predict average battery temperature and maximum temperature difference on the battery surface which are also the artificial neural network outputs. The model inputs are depth of discharge, coolant flow rate (0.1, 0.6 and 1.1 l/min), discharge rate (1C- 5C), coolant inlet temperature (15, 25 and 35 °C). It is developed for a serpentine tubed cold plate, and mini channeled one which has novel design. To shorten the training time, after the optimization of the data set, a total of 270 data sets were utilized for training, validation, and test phases. In addition, the developed model predicts successfully average battery temperature and maximum temperature difference on the battery surface in the 10% error band range. Finally, the maximum margin of deviation and R values are 7.3% and 0.997%, respectively.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2022Multi-objective optimization of a mini channeled cold plate for using thermal management of a Li-Ion battery
Kalkan, Orhan; Celen, Ali; Bakirci, Kadir
Mini channeled cold plates (MCCP) are an impressive choice for electric vehicles with a liquid-based thermal management system to keep the battery temperature within the desired range and to achieve a homogeneous temperature distribution. This paper came up with an optimum solution for maximum battery temperature (MBT), maximum temperature difference on the battery surface (MTD) and pressure drops in the channels (ΔP), which are vital parameters. Multi-objective optimization of geometric parameters and coolant flow rate of a designed MCCP which is experimentally investigated is carried out using the Desirability Function Approach. Firstly, the design of experiments (DoE) is generated using response surface method after determining the input variables and their levels. Then, each sample of DoE are modeled and analyzed numerically. Furthermore, the regression equations of the objective functions (MBT, MTD and ΔP) depending on the design parameters are developed and their variance analyzes are performed. Prediction accuracies of model equations developed for MBT, MTD and ΔP are 97.75%, 95.49% and 97.15%, respectively. As a result, optimum values of design variables, namely channel width (mm), distance between branches (mm), channel depth (mm), number of crossovers in branches and coolant flow rate (l/min) are 5, 5, 10, 13 and 0.7061, respectively.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2022Effect of climate change to solar energy potential: a case study in the Eastern Anatolia Region of Turkey
Bakirci, Kadir; Kirtiloglu, Yusuf
Architects, hydrologists, agriculturists, and solar engineers require the data of solar radiation for solar technologies such as solar drying, cooking, heating, and building illuminations. The aim of this study is to evaluate the effect of climate change on the potential of solar energy in the Eastern Anatolia Region (EAR) of Turkey. The global warming problem caused by greenhouse gases is increasing due to the increase in the use of fossil origin fuels in our world, and climate change is coming out. In this content, the values of monthly sunshine duration and global solar radiation are provided by the Meteorological Service in Turkish for the EAR of Turkey in the periods between 1987 and 2010. Thus, in a period of 24 years, it is investigated how much change took place in meteorological data. These changes are examined in the two different periods. In conclusion, it is observed that important changes occur in some meteorological data. The highest decrease in the variation amount of yearly average global solar radiation is seen in Erzurum, while the highest increase is seen in Erzincan. The highest increase in the variation amount of yearly average sunshine duration is seen in Erzincan, while the highest decrease is seen in Bitlis. In addition, the statistical analysis (t-test) is made to determine whether the difference between two periods is statistically significant for a considered region.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2021Experimental investigation of thermal performance of novel cold plate design used in a Li-ion pouch-type battery
Kalkan, Orhan; Celen, Ali; Bakirci, Kadir; Dalkilic, Ahmet Selim
The world's tendency towards electric vehicles has accelerated and the thermal management of them are critical part of the actual studies. Liquid-based cooling is known as the most common one among other cooling techniques. However, there is still need on the use of various heat transfer enhancement techniques to reduce the maximum temperature and maintain homogenous temperatures. This study experimentally investigated thermal performance of water-cooled cold plates used in thermal management of batteries by using conventional serpentine tube and a novel mini channel designs including a lithium-ion phosphate battery under certain discharge rates from 1C to 5C. Experiments are conducted for different water flow rates from 0.1 to 1.1 L/min as the coolant with inlet temperatures from 15 to 35 °C. Experimental results show that lower coolant inlet temperature causes the largest maximum temperature difference on battery surface. The use of mini channel cold plate resulted in 5.7 °C reduction in the maximum average battery surface temperature compared to serpentine one. Battery surface temperature homogeneity is improved up to 40% for operating conditions for mini channel cold plate usage. Thus, enhancement on thermal performance of proposed new mini channel cold plate is accomplished by temperature measurements.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2021Experimental and numerical investigation of the LiFePO4 battery cooling by natural convection
Kalkan, Orhan; Celen, Ali; Bakirci, Kadir
In this study, the thermal performance of a LiFePO4 (LFP) pouch type battery in the range of 1C-5C discharge rate at 23 °C ambient temperature and natural convection conditions is experimentally and numerically investigated. Time-dependent temperature changes of the battery are imaged with a thermal camera for each discharge, and the maximum, minimum and average changes on the battery surface are examined. In addition, the heat transfer rate through the battery is calculated for each discharge rate under natural convection conditions of the battery, and the temperature and velocity distributions on the battery surface are investigated. For the experiment with the highest discharge rate (5C), the measured maximum and average battery temperatures are determined as 52.2 °C and 50.1 °C, respectively. The calculated maximum temperature difference on the battery surface is also 6.7 °C. Moreover, the homogeneity index defined for battery surface temperature is 0.147 at 5C discharge rate. It has been observed that natural convection cooling is not sufficient for the battery at high discharge rates Furthermore, a new correlation equation has been proposed for the estimation of the heat transfer rate from a 20 Ah LFP pouch type battery under natural convection conditions at 23 °C ambient temperature.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2018Prediction of diffuse solar radiation using satellite data
Bakirci, Kadir; Kirtiloglu, Yusuf
In the project of the solar systems, the values of the solar radiation of a region must be known. The global solar radiation measurements are performed by the Turkish Meteorological Service in Turkey, while the diffuse solar radiation measurements are unavailable. In this study, some new models for predicting the monthly average daily diffuse solar radiation on a horizontal surface for Erzincan, Turkey are developed using satellite data. The evaluation of the models is carried out with the statistical analysis methods of mean bias error (MBE), root mean square error (RMSE) and correlation coefficient (r). The results are proved that the correlation equations obtained in here can be used to forecast diffuse solar radiation reasonably well.
RDL Kalıcı Kaydıİncele - Conference ObjectYalnız künye2012The relation of collector and storage tank size in solar heating systems
Çomakli, Kemal; Çakir, Uǧur; Kaya, Mehmet; Bakirci, Kadir
The most popular method to benefit from the solar energy is to use solar water heating systems since it is one of the cheapest way to benefit from the solar energy. The investment cost of a solar water heating system is very low, and the maintenance costs are nearly zero. Using the solar energy for solar water heating (SWH) technology has been greatly improved during the past century. A storage tank is used in many solar water heating systems for the conservation of heat energy or hot water for use when some need it. In addition, domestic hot water consumption is strongly variable in many buildings. It depends on the geographical situation, also on the country customs, and of course on the type of building usage. Above all, it depends on the inhabitants' specific lifestyle. For that reason, to provide the hot water for consumption at the desirable temperature whenever inhabitants require it, there must be a good relevance between the collectors and storage tank. In this paper, the optimum sizes of the collectors and the storage tank are determined to design more economic and efficient solar water heating systems. A program has been developed and validated with the experimental study and environmental data. The environmental data were obtained through a whole year of operation for Erzurum, Turkey.
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