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- ArticleYalnız künye2019Performance assessment of solar-powered high pressure proton exchange membrane electrolyzer: A case study for Erzincan
Ganjehsarabi, Hadi
In this study, a performance assessment of a solar-powered high-pressure proton exchange membrane (PEM) electrolyzer for hydrogen production is conducted. The feasibility analysis of photovoltaic systems equipped with a high pressure PEM electrolyzer is presented for a university campus-scale community in Erzincan- Turkey. Variable solar irradiance data sets are utilized to assess the performance of the proposed system. A parametric study is conducted in order to evaluate the influence of some design parameters as well as operating conditions on the efficiency of the system. Efficiency of the overall system in the case of relevant inverter sizing is in the range of 11–12%. An ascent of the number of stacks leads to an increase in production rate which is almost linear by photovoltaic (PV) array size. The results shows that in order to have a higher efficiency, the inverter size should be higher than 0.75% of maximum excess power. The proposed system investigated in this study shows great promise of opening up opportunity to develop the high pressure PEM electrolyzer.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2019Mixed refrigerant as working fluid in Organic Rankine Cycle for hydrogen production driven by geothermal energy
Ganjehsarabi, Hadi
The possibility of utilizing low temperature heat source systems for producing electricity has been significant due to increasing energy demand. In this study, the Organic Rankine Cycle (ORC) integrated with proton exchange membrane (PEM) electrolyzer is analyzed thermodynamically and economically. A mixture of butane, pentane and iso-pentane is selected as working fluid. The results show that utilizing the mixed refrigerant enhances the performance of the system and results in a higher hydrogen production rate because of a glide match of temperature profiles in the heat exchangers. Economic analysis results which are helpful in designing entire the system show that the highest cost component is electrolyzer, followed by the turbine and condenser.
RDL Kalıcı Kaydıİncele - Book ChapterYalnız künye2018Thermodynamic performance assessment and comparison of active magnetic regenerative and conventional refrigeration systems
Ganjehsarabi, Hadi; Dincer, Ibrahim; Gungor, Ali; Aloui, F; Dincer, I
Comprehensive thermodynamic analyses, performance assessments, and comparative evaluations of active magnetic regenerative (AMR) and conventional vapor-compression-based refrigeration systems are presented in this study. The active magnetic regenerative (AMR) uses a magnetic material as a thermal storage medium and as a refrigerating medium. A parametric analysis is to investigate the influences of various operating conditions and/or parameters on the thermodynamic performance of the AMR cycle. In this regard, these performance results are compared with the published experimental data for a traditional refrigeration system with the same refrigeration capacity and temperature span. The results of this particular study show that the COP of the AMR cycle changes very little with varying hot source temperature. It is shown that the conventional vapor-compression-based refrigeration cycles offer better performance than the active magnetic regenerative refrigeration systems.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2018Thermoeconomic modeling and multi-objective evolutionary-based optimization of a modified transcritical CO2 refrigeration cycle
Khanmohammadi, Saber; Goodarzi, Mohsen; Khanmohammadi, Shoaib; Ganjehsarabi, Hadi
In this study, thermoeconomic optimization is applied to a modified transcritical (CO2) refrigeration cycle. Modified cycle includes an extraction of saturated vapor as a coolant stream from the separator feed to the intercooler. In order to perform multi criteria optimization two objective functions consist of cooling capacity and annual cost rate are chosen. Gas cooler temperature (Tgc), gas cooler pressure (Pgc), extraction mass flow rate (α) and evaporator temperature (Tev) are selected as decision variables based on parametric study. The thermodynamic and economic modeling of the system is performed. To determine analytical, objective functions GMDH (group method of data handling) neural network method is used and finally with a developed code in Matlab optimal values of decision variables have been obtained. In addition, to better understanding the change of decision variables in optimum point, the scatter distribution of these variables is carried out.
RDL Kalıcı Kaydıİncele - Book ChapterYalnız künye2018Numerical simulation of building wall integrated with phase change material: A case study of a Mediterranean City Izmir, Turkey
Asker, Mustafa; Alptekin, Ersin; Tokuç, Ayça; Ezan, Mehmet Akif; Ganjehsarabi, Hadi; Nizetic, S; Papadopoulos, A
Nowadays, improving the energy efficiency of buildings without decreasing the comfort of its occupants is of great importance in the whole world. The most widespread passive energy control strategy is the utilization of insulation materials with low thermal transmittance. This chapter proposes an alternative control strategy that would help to create more stable temperatures inside a room. This is changing the thermal capacity of a common wall with the integration of phase change material (PCM). To evaluate the performance of the PCM, user-defined scripts are coded in commercial CFD solver ANSYS FLUENT to simulate one-dimensional heat transfer through a wall within a detached cabin in a city with Mediterranean climate for 1 day in the hot season. The placement and amount of PCM in the building element are changed and analyzed. The results show a decrease in the indoor wall temperature up to 6 °C, which is promising for further research.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2018Numerical investigation of inward solidification inside spherical capsule by using temperature transforming method
Asker, Mustafa; Ganjehsarabi, Hadi; Turhan Coban, M.
In this study, a numerical analysis of the inward solidification of phase change material inside spherical capsule is carried out. The spherical capsule that is subjected to convection from the outside surface initially is not at its melting temperature. The control volume approach and temperature transforming method are applied to solve the dimensionless energy equation. The model solution results are validated through a comparison with published experimental data for similar case and it shows a considerably good agreement. The analysis results show that the larger diameter spherical capsules have significantly greater solidification time compared to those with smaller diameters of spherical capsules. In addition, the entropy generation inside spherical capsule is analyzed. It is found that the entropy generation increases with increasing sphere capsule diameter, attains a maximum and then decreases.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2018Assessment of different bio-inspired flow fields for direct methanol fuel cells through 3D modeling and experimental studies
Ouellette, David; Ozden, Adnan; Ercelik, Mustafa; Colpan, C. Ozgur; Ganjehsarabi, Hadi; Li, Xianguo; Hamdullahpur, Feridun
The performance impact of using bio-inspired interdigitated and non-interdigitated flow fields (I-FF and NI-FF, respectively) within a DMFC is investigated. These two flow fields, as well as a conventional serpentine flow field (S-FF, used as a reference), were examined as possible anode and cathode flow field candidates. To examine the performance of each of these candidates, each flow field was manufactured and experimentally tested under different anode and cathode flow rate combinations (1.3 mL/min [methanol] and 400 mL/min [oxygen], as well as 2 and 3 times these flow rates), and different methanol concentrations (0.50 M, 0.75 M, and 1.00 M). To help understand the experimental results and the underlying physics, a three dimensional numerical model was developed. Of the examined flow fields, the S-FF and the I-FF yielded the best performance on the anode and cathode, respectively. This finding was mainly due to the enhanced under-rib convection of both of these flow fields. Although the I-FF provided a higher mean methanol concentration on the anode catalyst layer surface, its distribution was less uniform than that of the S-FF. This caused the rate of methanol permeation to the cathode to increase (for the anode I-FF configuration), along with the anode and cathode activation polarizations, deteriorating the fuel cell performance. The NI-FF provided the lowest pressure drops of the examined configurations. However, the hydrodynamics within the flow field made the reactants susceptible to traveling directly from inlet to outlet, leading to several low concentration pockets. This significantly decreased the reactant uniformity across its respective catalyst layer, and caused this FFs performance to be the lowest of the examined configurations.
RDL Kalıcı Kaydıİncele - Conference ObjectYalnız künye2018Entropy generation analysis of multilayer PCM slabs integrated with fins
Asker, Mustafa; Alptekin, Ersin; Ezan, Mehmet Akif; Ganjehsarabi, Hadi
In this study, the utilisation of composite phase change materials (PCMs) slabs with fins in a thermal energy storage (TES) system is numerically analysed. The storage system consists of three PCM layers at different melting temperatures. First, the predicted results are verified against the analytical solution that is taken from literature. Afterwards, the influence of the design parameters such as fin length and fin spacing on time for complete melting of the multi-layer TES are examined. Custom field functions are integrated into the ANSYS-FLUENT software to assess the local and volume averaged entropy generation within the system. The results show that at constant fin spacing, that increasing fin length from 20 mm to 80 mm enhances the melting rate up to 50%. In addition, when the fin spacing is doubled, the elapsed time for complete melting decreased about 37%. Moreover, the fin arrangement has a considerable effect on entropy generation.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2017Designing, modeling and performance investigation of bio-inspired flow field based DMFCs
Ozden, Adnan; Ercelik, Mustafa; Ouellette, David; Colpan, C. Ozgur; Ganjehsarabi, Hadi; Hamdullahpur, Feridun
In an attempt to improve upon conventional flow fields (e.g., serpentine flow field), Murray's Law was applied to design two different bio-inspired, leaf-shaped flow fields. This law governs the dimensions of natural networks, such as: the veins within plant leaves and human lungs. In this study, the serpentine, the lung, and the two leaf-shaped flow fields were used to form seven different anode–cathode combinations. The experiments focused on the effects of methanol concentration (0.50 M, 0.75 M, and 1.00 M) and the combined effect of methanol and oxygen flow rates (1.3 ml/min methanol and 400 ml/min oxygen, as well as 2 and 3 times both of these flow rates). An analytical model was also developed to help understand the experimental results. The results show that the highest performance could be achieved when the bio-inspired configurations were used on the cathode. The best configuration was the serpentine (anode) – second leaf design (cathode), with a peak power density of 888 W/m2. For comparison, a peak power density of 824 W/m2 was achieved when the serpentine flow field was used on the anode and cathode. Furthermore, of all the tested configurations, the lung-based flow field provided the lowest performance in all tests.
RDL Kalıcı Kaydıİncele - Conference ObjectYalnız künye2016Analysis and optimisation of a cascade active magnetic regenerative refrigeration system
Ganjehsarabi, Hadi; Dincer, Ibrahim; Gungor, Ali
In this paper, comprehensive thermodynamic analysis and optimisation of a cascade active magnetic regenerative refrigeration system are performed. A parametric study is conducted to investigate the effects of various design parameters on the cycle performance through energy and exergy efficiencies. A multi-objective optimisation method based on a fast and elitist non-dominated sorting genetic algorithm is applied to determine the best design parameters for the system. Two objective functions utilised in the optimisation study are the total cost rate of the system and the system exergy efficiency. The total cost rate of the system is minimised while the cycle exergy efficiency is maximised using an evolutionary algorithm. To provide insight, the Pareto frontier is shown for a multi-objective optimisation. The results show that exergy efficiency could be increased by 14.53% using exergy-based optimisation and the cost could be reduced by 12% using the cost-based optimisation.
RDL Kalıcı Kaydıİncele - Conference ObjectYalnız künye2016Energy and exergy analyses of a solar assisted combined power and cooling cycle
Ganjehsarabi, Hadi; Asker, Mustafa; Seyhan, Aslihan Kurnuc
In this study, a thermodynamic analysis of a solar assisted Rankine-Goswami integrated cycle is carried out for a range from 230 to 240 MW sizes. To illustrate the performance characteristics of these integrated cycle, an exergy analysis is conducted to pinpoint the losses due to internal and external irreversibilities of each component. In addition, the effect of design parameter such as condenser pressure on the performance of the integrated cycle is examined. The results shows that the variation of condenser pressure from 4 kPa to 24 kPa greatly reduces the exergy efficiency of the system. Moreover, it is found the exergy efficiency of standard solar assisted Rankine cycle case is 42.8% whereas the exergy efficiency of solar Rankine-Goswami multigeneration system is 47.03%.
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