Sürdürülebilir Kalkınma Amaçları
Yayınlar
- ArticleAçık Erişim2026The Effect of Fin Parameters on Cooling of Lithium-ion Batteries: Numerical Analysis and Optimization
Kalkan, Orhan; Demir, Fatih
Lithium-ion batteries are frequently preferred for electric vehicles and diverse applications due to their high energy density, high specific energy, and superior efficiency. Despite these advantages, they generate substantial heat during charge and discharge at high C-rates, which can lead to thermal runaway. Thus, an appropriate Battery Thermal Management System is necessary to prolong their lifespan and maintain performance and capacity. This study considers a passive cooling technique for cooling a Lithium-ion battery using fins. The effect of fin geometric parameters on battery thermal management was numerically investigated, and optimal values were determined through multiple optimizations, thereby contributing to the literature. For this purpose, analyses were obtained for varying diameters (20 mm-36 mm), thicknesses (0.5 mm-2 mm), and numbers (3-9) of cylindrical fins placed on a cylindrical battery at a high discharge rate of 5C. In the results, battery surface temperatures, battery temperature difference, and mass were evaluated in detail. Next, the maximum and average battery temperatures, the maximum and minimum temperature differences for homogeneity, and mass were selected as objective functions for multiple optimizations. The I-optimal algorithm based on the Response Surface Method was used to create a Design of Experiment. Optimization parameters and levels were determined by numerical analysis. The mathematical models derived for the selected performance parameters (maximum temperature (Tmax), average temperature (Tavg), maximum and minimum temperature difference (∆T) for homogeneity, and mass were tested using ANOVA, with prediction accuracies of 0.9923%, 0.9866%, 0.9381%, and 0.9314%, respectively. The results indicate that increasing the fin diameter (from 20 to 36 mm) decreases Tmax by 3.4% and Tavg by 3.7%, but increases mass by 12.2% and ∆T by 5 K to 11 K. Moreover, as fin thickness increases from 0.5 mm to 2 mm, Tmax and Tavg decrease by 2.2%, but increases mass by 21% and ∆T by 9.8 K to 10.8 K. Furthermore, as the number of fins increases from 3 to 9, Tmax and ∆T decrease by 6.0% and 36.3%. Increasing the number of fins is more effective at increasing homogeneity than increasing their diameter and thickness. Optimization results show that with a fin diameter of 32.4 mm, a thickness of 1.35 mm, and 9 fins, the battery temperature can be maintained below 349 K under these optimal conditions.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2026GMDH and NSGA-III based design optimization of bio-inspired cooling systems for prismatic LFP batteries
Kalkan, Orhan
This study presents a high-fidelity multi-objective optimization of bio-inspired cold plates (Ginkgo, Tilia, Tulip) for prismatic LFP battery thermal management. The coupled effects of mass flow rate (0.5–20 g s−1), inlet temperature (5–30°C), and glycol volume fraction (0–60%) on maximum battery temperature (Tmax), temperature non-uniformity (ΔT), and pressure drop (ΔP) are systematically examined under a 3C discharge rate. Numerical reliability is confirmed via GCI, with experimental validation showing a maximum error of 9.83%. To overcome the limitations of conventional regression, the Group Method of Data Handling (GMDH) is utilized to develop precise surrogate models, which are subsequently coupled with the Non-dominated Sorting Genetic Algorithm III (NSGA-III) for multi-objective optimization. The optimization identifies a robust, feasible Pareto front that strictly adheres to the safety constraints of 15°C ≤ Tmax≤35°C and ΔT≤5°C. Quantitative results reveal 10 candidate optimal designs, with Design 1 offering the highest efficiency at a minimum pressure drop of 1058.96 Pa, and Design 10 providing maximum thermal safety with a Tmax of 32.18°C. Furthermore, integrating freezing-point constraints enables climate-adaptive selection; designs with glycol fractions up to 58.43% ensure system integrity down to −49°C, albeit with a 58% increase in hydraulic penalty compared to the base optimal design.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2026Comparative study of diverging and converging coaxial jet nozzles for thermal management of H-CPV modules
Demir, Fatih; Kalkan, Orhan
Jet impingement cooling is widely recognized as one of the most effective methods for achieving high heat transfer rates in compact systems, making it particularly suitable for cooling photovoltaic devices. This paper investigates the effects of newly designed coaxial nozzle configurations on the thermal management of a high-concentration photovoltaic system. Four different nozzle geometries, such as square, circular, hexagonal, and triangular, are considered, with constant outer cross-sectional areas, while the inner sections are designed to diverge or converge. Simulations are performed for Reynolds numbers of 2000–4000 and dimensionless coaxial nozzle-heat sink distances of 0.5–3. The results reveal that the coaxial nozzle enhances heat transfer performance compared to conventional nozzles. The diverged triangular coaxial nozzle achieves the best heat transfer at a Reynolds number of 4000, with a 19 % increase in the modified Nusselt number compared to the conventional triangular nozzle. The highest temperature uniformity (6.39 °C) is observed in the converged hexagonal coaxial nozzle, while the lowest maximum and average cell temperatures (46.1 °C and 44 °C) are achieved with the diverged triangular coaxial nozzle. The lowest pressure drop (1297 Pa) is found in a diverged hexagonal coaxial nozzle, corresponding to the lowest net electrical power (17.53 W) and cell efficiency (38.97 %). Despite the pressure drops, the diverged triangular coaxial nozzle achieves the highest electrical efficiency of 39.41 %, as its geometry promotes favorable power generation. The coaxial configuration increases the cell efficiency by up to 1.13 % and improves temperature uniformity by 23.3 %. Total exergy follows the same trend as electrical exergy, with the converged hexagonal coaxial nozzle exhibiting the highest total exergy efficiency of 38.35 %. The findings demonstrate that coaxial nozzles can significantly improve thermal uniformity and system efficiency in high-concentration photovoltaic cooling applications.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2026The thermal-hydraulic performance evaluation of a triangular groove duct with L-shaped baffles: Multi-objective optimization and numerical analysis
Ekiciler, Recep; Demir, Fatih; Kalkan, Orhan
Enhancing heat transfer efficiency is crucial for improving performance and reducing the energy consumption of thermal equipment in various industrial sectors. The emergence of passive enhancement methods, such as corrugated grooves, has improved convective heat transfer cost-efficiently. To this end, this study addresses the thermal and hydraulic performance of the baffle duct with numerical analysis and multi-objective optimization methods. The study is innovative in that it places movable L-shaped baffles inside the duct, which have their own internal connections and a connection to the grooved channel. L-shaped baffles have the ability to move at alpha angles (α = 30°, 60°, 90°) with the upper wall of the duct and at beta angles (β = 60°, 90°, 120°, 150°) with their internal connection points, which affect the thermal and hydraulic performance of the duct. Air, water, mono (GO/water), and tetra hybrid (Al2O3-Au-Ag-TiO2/water) nanofluids are used as coolant fluids in the range of Re = 2500 to 3100. The coolant air and a baffle-less triangular grooved duct are used for comparison to evaluate the thermal and hydrodynamic performance in other cases. The results show that at Re = 2500, the baffled duct achieves a 65% higher Nu than the one without baffles. As α = 90° decreases to 30°, Nu increases by 12.85% and 12.11%, respectively. As β = 60° to 120° increases, Nu increases by 21.67%, while f increases by 59% from β = 90° to 120°. The highest performance evaluation criteria (PEC) is achieved at β = 90° and the lowest at β = 150°. The tetra hybrid nanofluid exhibits the highest Nu and f values across all Re ranges, demonstrating the most efficient cooling performance with a PEC value approximately 8% higher than that of water. Multi-objective optimization reveals that the combination of α = 30°, β = 35°, Re = 2500, and water is the most suitable design. Generally, thermal and hydraulic performance can be significantly improved by carefully selecting channel geometry and fluid properties.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024Mikro İşlemciler için Sıvı Metal Soğutmalı Mini Kanallı Soğutucularda Kanatçık Kullanımının Termohidrolik Etkilerinin İncelenmesi
Kalkan, Orhan
İşlem hızı giderek artan mikro işlemcilerin etkin soğutmaya olan ihtiyaçları da aynı ölçüde artış göstermektedir. Bu ise daha etkili soğutma yöntemleri üzerinde çalışmaları artırmaktadır. Sıvı metaller ile soğutulan mini/mikro kanallı soğutucular, yüksek ısı iletim katsayıları nedeni ile etkin soğutma sağlayabilmektedirler. Bu çalışmada, Galinstan ile soğutulan bir mini kanallı soğutucuda, kanatçık kullanımının ısıl direnç katsayısına ve oluşan basınç kaybına etkileri incelenmiştir. Kanatçıkların farklı konfigürasyonlarda kanal içinde yerleşimi ile oluşturulan ve toplamda 70 farklı modelden oluşan sayısal analiz sonucunda; kanatçıklar arası mesafenin 1,5 mm altında olması durumunda kayda değer bir ısıl performans iyileşmesi gözlemlenmemekle birlikte aşırı basınç kaybı oluşturduğu belirlenmiştir. Kanatçık boyunun 0,3 mm ve kanatçıklar arası mesafenin 1,5 mm olduğu durumda, kanatçıksız duruma göre minimum akışkan giriş hızı koşulunda %15,9 oranında ısıl performans iyileşmesi elde edilmiştir. Diğer yandan ise bu durumda 95 kPa değerinde basınç kaybı artışı yaşanmıştır.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024A COMMERCIAL TURBOFAN ENGINE MODELING AND EXERGY ANALYSIS
Kalkan, Orhan
Turbofan engines are one of the most common types of engines used in modern commercial and military aircraft due to their efficiency and performance characteristics. In this study, a thermodynamic model is generated using GasTurb 14 software for a commercial two-spool, unmixed flow, and booster turbofan engine (CFM56-5A3) used in Boeing A320-212. Besides, an exergy analysis of the modeled turbofan engine is performed. Exergy performance criteria such as exergy efficiency, exergy development potential, exergy destruction ratio, productivity lack ratio, and fuel depletion ratio are evaluated for the engine components. In addition, how bypass ratio (BPR) affects net thrust and specific fuel consumption (SFC) for the modeled turbofan engine is investigated. As a result, the net thrust and SFC values of the modeled engine and the actual engine are overlapped with 14.0% and 7.2% deviation, respectively. The maximum exergy efficiency occurs at the high-pressure turbine as 0.992. When the bypass ratio is minimum, the maximum net thrust and SFC occur as 62.24 kN and 24.08 g kN(-1) s(-1) , respectively. High pressure turbine has the minimum exergy development potential of 1528.5 kW.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2024Thermal performance improvement of an air-cooled 18650 NMC battery module: A novel busbar design that acts as a turbulator
Kalkan, Orhan
Today, Lithium-ion batteries are preferred as popular energy storage tools in many fields such as electronic devices, especially electric vehicles. During the discharge of modules and packs formed by combining many battery cells, undesirable temperature increases are experienced due to excessive heat generation. Thus, thermal management of the battery packs is crucial. In this work, thermal and hydraulic performance analysis of the two air-cooled 18650 NMC battery modules, one with a novel designed twisted busbar and the other with a conventional busbar, are performed numerically. Temperature and pressure drop predictions are achieved at different values of air inlet velocity, discharge rate, depth of discharge, and twist diameter of busbar using CFD method. Besides, the Multi-Scale Multi-Domain battery model is validated experimentally. According to the numerical results, the novel designed twisted busbar provides 1.84 %, 2.93 %, and 3.81 % reduction in maximum battery module temperature for 5 m/s air inlet velocity under discharge rates of 2C, 3C and 4C, respectively. The average battery module temperature drops by 6.6 °C thanks to the use of a twisted busbar. Using a twisted busbar results in a maximum pressure drop increase of 119 Pa compared to the conventional busbar. As the twist diameter of the busbar increases, the battery temperature decreases significantly, and the pressure drop increases, especially at high air velocity conditions. In addition, when the twist diameter increases from 5 mm to 15 mm, the weight/volume ratio increases by approximately 0.9 %.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024Immersion cooling of a cylindrical battery module: An optimum configuration using CFD, NSGA-II and desirability function approach
Kalkan, Orhan
Immersion cooling offers promising advantages for cylindrical battery modules, particularly in applications where compact design, efficient thermal management, and enhanced safety are critical factors. In this study, the geometric, thermal, and dynamic parameters of an immersion-cooled battery module with 14 NCM cylindrical cells are analyzed using CFD methods. The developed battery model is experimentally validated, establishing the constraints through numerical analysis of the impact of design parameters on response values. The design parameters are optimized using a multi-objective optimization technique. The study models the battery module with mineral oil cooling and examines the impact of each parameter on variables such as maximum battery module temperature (Tmax), pressure drop (ΔP), maximum temperature variance (ΔTmax), and battery module mass index (Im). A Design of Experiment set, created with Central Composite Design (CCD), is solved using CFD methods, and quadratic correlation equations are derived using backward regression. The regression models for Tmax, ΔTmax, ΔP, and Im show high accuracy with R2 values close to 1.0. Optimization is performed using the entropy weight-based composite desirability function approach, yielding optimum values for cell center spacing (t), coolant mass flow rate (ṁc), and coolant inlet temperature (Ti) at 20.606 mm, 1.5 kg/s, and 23 °C, respectively. The optimized design sets are validated through CFD analysis, showing a maximum deviation of 4.27 %. Reducing t boosts thermal performance but lowers hydraulic performance, while the reverse occurs for ṁc. As Ti decreases, effective cooling improves, but temperature uniformity suffers.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2023Development of Chip Temperature and Cost-Based Optimum Design for a Radial Heat Sink Cooling High Power LEDs
Kalkan, Orhan
High power Light Emitting Diodes (LED)s are preferred in places that produce intense light output and have overheating problems because they work with high currents. Therefore, efficient thermal management is essential to ensure optimal performance and longevity. In the present study, a numerical analysis is conducted on a high-power Light Emitting Diode (LED) circuit with a Circuit on Board (COB) design featuring a radial heat sink. Additionally, a multi-objective optimization approach using the Desirability Function Approach (DFA) is introduced for the modeled radial heat sink. Two performance parameters, namely the maximum junction temperature and the cost of the radial heat sink, are defined as the objective functions, and the aim is to minimize both of these parameters. The independent variables for the objective functions are the geometrical parameters of the radial heat sink, namely the base radius (R), fin length (L), and heat sink height (H). The Response Surface Method (RSM) is applied to minimize sample numbers of the Design of Experiment (DOE) while still obtaining accurate response values. Furthermore, Analysis of Variance (ANOVA) is utilized to assess the fitting of the real response equations with the representative answer equations. The minimum prediction R2 is calculated to be 0.9748%, indicating a good agreement between the models. The optimum design for the radial heat sink is obtained, with the following dimensions: R=25 mm, L=15 mm, and H=55.36 mm. The response values for this optimal design are validated with a low error rate of 0.25% using numerical analysis.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2023Multi-objective optimization of a liquid metal cooled heat sink for electronic cooling applications
Kalkan, Orhan
Recently, studies on the use of MCHS applied to chips to benefit from the high thermal conductivity of liquid metals have been increasing. This study came up with an optimum choice for MCHS geometric parameters, MCHS material, Gallium-based liquid metal coolant type, and coolant inlet velocity. Total thermal resistance (Rtot), initial investment cost (Ci), pressure drop (ΔP), and maximum operating temperature (Tmax) are selected as performance parameters. I-optimality algorithm used for generation of the Design of Experiment (DoE) based on the Response Surface Method. The optimization parameters and their levels are determined by performing a parametric study. The derived mathematical models for selected performance parameters Rtot, Ci, Tmax, and ΔP, which are also objective functions, are tested by ANOVA with prediction accuracy of 0.983%, 0.997%, 0.886%, and 0.996%, respectively. As a result, the determined optimum values of the channel width, channel height, half of fin width, fin slope angle, and inlet velocity, are 1.16 mm, 3.00 mm, 0.24 mm, 5.96°, and 0.4 m s−1, respectively. In addition, a hybrid structure in which the base of the designed MCHS is aluminum, and the fins are copper, and the GaIn compound for the coolant are calculated as the optimum material options.
RDL Kalıcı Kaydıİncele - 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 - Review ArticleAçık Erişim2021The Investigation of Batteries and Thermal Management Systems Used in Electric Vehicles
Celen, Ali; Kaba, Muhammet Yasin; Kalkan, Orhan
Nowadays, electric vehicles come to the fore more than vehicles with internal combustion engines since electric vehicles are environmentally friendly and highly more efficient. Selection and thermal management of the battery, which is one of the most important equipment that constitutes electric vehicles, is important. In this study, the general view (history, classification, sales numbers, market shares) of electric vehicles, battery types that can be used in electric vehicles and battery thermal management systems were investigated. Different types of batteries commonly used in applications are compared according to their characteristics, and among these batteries, it has been observed that the type of battery that can be used in electric vehicles is lithium-ion batteries which have high specific energy (118-250 Wh/kg), high energy density (200-400 Wh/L), high specific power (200-430 W/kg), high cycle life (2000) and ideal operating temperature (-20oC-60oC). The thermal management systems, which can be used to obtain maximum performance from these batteries, are investigated and advantages and disadvantages of these methods are investigated. While it has been seen that air cooling is sufficient in vehicles with low thermal load (hybrid electric vehicles, etc.), it is observed that the use of liquid and hybrid cooling methods is appropriate in vehicles with high thermal load (full electric vehicles).
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2021Numerical investigation on the usage of finned surface in lithium nickel manganese cobalt oxides batteries by using air cooling method
Celen, Ali; Kalkan, Orhan
In this study, a numerical thermal analysis of a lithium nickel manganese cobalt oxide prismatic battery having nominal voltage of 3.7 V and capacity of 26Ah was performed during air cooling conditions. The effects of discharge rate (in the range of 3C-5C) and air velocity (in the range of 1-3 m s(-1)) on average battery temperature, maximum battery temperature, and total heat transfer rate are investigated for both flat and finned cooling surfaces. The results showed that air cooling by means of flat cooling surface is only sufficient for low discharge rate and it is necessary to use finned surfaces in order to keep battery temperature in desired operation temperature range for high discharge rate conditions. Analysis results showed that average battery temperature is reduced up to 29%, 32%, and 30% by increasing air velocity for discharge rates of 3C, 4C, and 5C with the usage of flat surface, respectively. In addition, it was seen that the average and maximum battery temperatures are reduced up to 7.9 and 8.6 K with the usage of finned cooling surface instead of flat one. The heat removed from the battery is increased 8.7 W by using finned surface at the maximum air velocity of 3 ms(-1).
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 - ArticleAçık Erişim2019Erzincan İlinde Bir Yeraltı Suyu Kaynaklı Isı Pompası Sisteminin Deneysel Performans Analizi
Kaya, Mehmet Nuri; Kalkan, Orhan
Bu çalışmada, Erzincan İlinde bulunan 80 m2 taban alanına sahip bir mekân Yeraltı Suyu Kaynaklı Isı Pompası (YASKIP) ile ısıtılmıştır. Deneysel olarak gerçekleştirilen bu çalışmada ısı pompasının ve tüm sistemin enerji ve performans analizi yapılmıştır. Buharlaştırıcı su debisi, yoğunlaştırıcı su debisi ve Fan-coil hava debisi belirli değerlerde sabitlenmiştir. Daha sonra bu parametrelerden oluşan 9 farklı koşulda ölçümler alınmıştır. En yüksek değerlerin alındığı koşulda, ısı pompasının ve tüm sistemin performans katsayıları sırasıyla 4.27 ve 2.92 bulunmuştur. Bu koşulda yoğuşturucudan atılan ortalama ısı yükü 14.32 kW olarak hesaplanmıştır. Diğer yandan, yeraltı suyu kalitesi ve sıcaklığı önemli bir kriter olan YASKIP sisteminin Erzincan için uygulanabilir olduğu belirlenmiştir.
RDL Kalıcı Kaydıİncele