abdulrazzak Akroot | Karabuk universitesi (original) (raw)
Papers by abdulrazzak Akroot
Journal of Advanced Research in Fluid Mechanics and Thermal Sciences
Renewable energy used for refrigeration applications has become essential very recently due to th... more Renewable energy used for refrigeration applications has become essential very recently due to the fossil fuel crisis and the global warming problem. Moreover, using photovoltaic PV to generate electricity than using inverters and energy storage represents a high-cost process. This study aims to investigate the opportunity of using PV output directly to operate a refrigeration system. The absorption refrigeration system uses heat as an energy source for the generator that drives the system. Moreover, the absorption refrigeration system doesn't have a compressor but a generator. As a result, the novel aspect of this study is the use of PV electricity's DC output to power the heater that provides the needed heat for the generator without the use of an inverter that provides AC electricity. The essential very difference here is that the compressor needs a consistent and steady electric supply. However, using DC electricity for heating is not very restricted if the voltage fluct...
Sustainability
This study focused on exergo–conomic and parametric analysis for Taji station in Baghdad. This st... more This study focused on exergo–conomic and parametric analysis for Taji station in Baghdad. This station was chosen to reduce the emission of waste gases that pollute the environment, as it is located in a residential area, and to increase the production of electric power, since for a long time, Iraq has been a country that has suffered from a shortage of electricity. The main objective of this work is to integrate the Taji gas turbine’s power plant, which is in Baghdad, with the Rankine cycle and organic Rankine cycle to verify waste heat recovery to produce extra electricity and reduce emissions into the environment. Thermodynamic and exergoeconomic assessment of the combined Brayton cycle–Rankine cycle/Organic Rankin cycle (GSO CC) system, considering the three objective functions of the First- and Second-Law efficiencies and the total cost rates of the system, were applied. According to the findings, 258.2 MW of power is produced from the GSO CC system, whereas 167.3 MW of power i...
International Journal of Heat and Technology
Sustainability
The heat exchanger is crucial to all systems and applications that use it. Researchers are primar... more The heat exchanger is crucial to all systems and applications that use it. Researchers are primarily focused on improving this component’s thermal conductivity to improve its efficiency. This was achieved by using one or more of the following strategies: inserting tapes with various shapes and numbers, inserting rings of various shapes and spacing between each, and transforming a basic liquid into a nanoliquid by adding nanomaterials with high conductivity and ultra-small particle sizes. Different types of nanomaterials were added in varying concentrations. In earlier studies, it was found that every increase in heat transfer was accompanied by a pressure drop at both ends of the exchanger. The amount of heat transferred and the pressure drop are affected by many factors, such as the torsion tape ratio, the pitch of the ring, and whether the pitch faces the direction of flow or not. Heat transfer rates can also be impacted by factors such as the length and angle of the wings, how ma...
International Journal of Design & Nature and Ecodynamics, Dec 31, 2022
Processes
Enhancing the sustainability and diversification of Iraq’s electricity system is a strategic obje... more Enhancing the sustainability and diversification of Iraq’s electricity system is a strategic objective. Achieving this goal depends critically on increasing the use of renewable energy sources (RESs). The significance of developing solar-powered technologies becomes essential at this point. Iraq, similar to other places with high average direct normal irradiation, is a good location for concentrated solar thermal power (CSP) technology. This study aims to recover the waste heat from the gas turbine cycle (GTC) in the Al-Qayara power plant in Iraq and integrate it with a solar power tower. A thermoeconomic analysis has been done to support the installation of an integrated solar combined cycle (ISCC), which uses concentrated solar tower technology. The results indicate that the examined power plant has a total capacity of 561.5 MW, of which 130.4 MW is due to the waste heat recovery of G.T.s, and 68 MW. is from CSP. Due to the waste heat recovery of GTC, the thermal and exergy effici...
In this study, a system-level zero-dimensional model for planar solid oxide fuel cellgas turbine ... more In this study, a system-level zero-dimensional model for planar solid oxide fuel cellgas turbine (SOFC/GT) hybrid system has been studied to investigate the effect of diverse operating conditions such as operating pressure, air utilization factor (Ua), and fuel utilization factor (Uf) on the performance of a selected hybrid system. Moreover, the system’s power production and performance were discussed in two various configurations: anode-supported model (ASM) and electrolyte-supported model (ESM). This study’s models were implemented in Matlab® to calculate the optimum operating parameters and determine the hybrid system’s performance characteristics. According to the finding, a maximum of 717.8 kW power is produced at 7.7 bar pressure for the ASM. In contrast, a maximum of 630.3 kW power is produced at 12 bar pressure for ESM. The highest electrical system efficiencies for the ASM and the ESM are 62.32% and 56.23%, respectively. Cite this article as: Akroot A, Namli L,. Performance...
Proton electrolyte membrane fuel cells (PEMFC) are promising power sources for automotive applica... more Proton electrolyte membrane fuel cells (PEMFC) are promising power sources for automotive applications because of their high power density, low operation temperature (between 60℃ - 80℃), and lower environmental pollution. A proper water and thermal management are needed to keep the membrane humidified for high proton conductivity, durability for PEMFC materials, and to ensure the operation temperature of fuel cell stack remains under a tolerable limit.A general calculation methodology has been developed to provide information regarding the system power output, amount of water and heat products, and system efficiency, thereby assisting to achieve the best water and thermal management conditions.Polimer membran elektrolit (PEM) yakıt hücreleri yüksek güç yoğunlukları, düşük çalışma sıcaklıkları (60℃ - 80℃ arası) ve düşük çevresel kirlilikleri nedeniyle otomotiv uygulamaları için umut verici güç kaynaklarındandır. Membranı nemli tutarak yüksek proton iletkenliğini sağlamak, polimer membran elektrolit yakıt hücresi malzemelerinin dayanıklılığı ve yakıt hücresinin çalışma sıcaklığının kabul edilir sınırlar altında kalması için uygun su ve termal yönetim gerekmektedir.Sistemin güç çıktısı, üretilen su ve ısı miktarı ve sistem verimliliği ile ilgili olarak bilgi sağlamak; ve böylece en iyi su ve termal yönetim koşullarına ulaşmak amacıyla genel bir hesaplama yöntemi geliştirilmiştir
Journal of Science and Technology, 2021
This paper uses the CFD technique to simulate the internal environment of a hospital operating ro... more This paper uses the CFD technique to simulate the internal environment of a hospital operating room, including the surgical area that includes the patientand the surgical team. Moreover, this work provides mathematical simulation of many models to be placed in the air entry and air exit areas in the operating room to obtainthe optimal model of air distribution within the operating room. The results obtained matched well with experimental data from approved literature and standards. These results found that airflow and air velocity significantly affect the patient’s thermal comfort in the operating room.Besides, it is observed that some recirculation zone is formed, and this is a result of the heat generated by the surgical team and the accelerated air. This region is considered a source for the survival of the polluted air in the room. Keywords: CFD, Operating room, Numerical analysis.
Journal of Electrochemical Energy Conversion and Storage, 2020
In this study, two solid oxide fuel cell (SOFC) hybrid systems (anode-supported model (ASM) and e... more In this study, two solid oxide fuel cell (SOFC) hybrid systems (anode-supported model (ASM) and electrolyte-supported model (ESM)) is developed in matlab® and compared. The hybrid system model is considered to investigate the impacts of various operating parameters such as SOFC operating temperature and steam/carbon ratio on power production and performance of the hybrid system where it is projected that results can be utilized as guidelines for optimal hybrid system operation. According to the findings, a maximum 695 kW power is produced at 750 °C operating temperature for the anode-supported model, whereas 627 kW power is produced at 1000 °C for the electrolyte-supported model. The highest electrical efficiencies for the anode-supported model and the electrolyte-supported model are 64.6% and 58.3%, respectively. Besides, the lower value of the steam to carbon ratio is favorable for increased power output from the fuel cell and consequently a high SOFC efficiency.
International Journal of Green Energy, 2019
A system level, steady-state thermodynamics model for an automotive PEM fuel cell system was deve... more A system level, steady-state thermodynamics model for an automotive PEM fuel cell system was developed to investigate the effects of vehicle speed and operating pressure on the size of the system components, heat and water formation, fuel consumption, fuel cell, and system efficiency. Moreover, the consequences of the choices of membrane's thickness and ionic conductivity on thermal and system efficiencies as a function of vehicle speed are analyzed. The model consists of a PEM fuel cell stack model and supplementary models for all necessary auxiliary components. Results show that increasing the system pressure has a significant positive impact on the water balance characteristics of the system, since less water is needed to reach the required relative humidity levels for the reactants. On the other hand, the high-pressure system requires more power in order to operate the compressor, which in turn, decreases the system efficiency. Decreasing air stoichiometry at high operating pressures improves the water management but has no effect at low pressures. Results also show that increasing the membrane's ionic conductivity and decreasing its thickness enhances the system efficiency especially at higher vehicle speeds. Lastly, it is obtained that the system efficiency decreases as the vehicle speed increases.
International Journal of Trend in Scientific Research and Development, 2019
This article presents a steady-state thermodynamic model of a solid oxide fuel cell/gas turbine h... more This article presents a steady-state thermodynamic model of a solid oxide fuel cell/gas turbine hybrid cycle which developed by using a simulation software, MATLAB®. The hybrid model integrates a zero-dimensional level SOFC model with gas turbine. The hybrid system was used to study the effects of some operation parameter such as SOFC operating temperature, and current density on the specific work output, electrical efficiency, and exergy efficiency of a generic hybrid cycle. The results show that if the SOFC operating temperature, the power output, electrical efficiency, and exergy efficiency increase. The electrical efficiency of the hybrid system increase from 62% to 68%, and the exergy efficiency of the hybrid system increases from 60% to 66% when the operation temperature increases from 600°C to 750°C at a current density of 6000 A/cm2. On the other hand, the system efficiency and exergy decreases with an increase in the current density.
The International Journal of Engineering and Science (IJES), 2020
Energy and exergy analyses are introduced to a zero-dimensional hybrid system of solid oxide fuel... more Energy and exergy analyses are introduced to a zero-dimensional hybrid system of solid oxide fuel cell-gas turbine, for steady-state operation. The effects of two important SOFC parameters (operating pressure and current density) on varying conditions are examined. According to the obtained results, a decrease in SOFC current density improved the system performance (electrical efficiencies and exergy efficiencies) due, primarily, to the reduction in Ohmic losses, which results in a higher stack voltage. As system pressure increases, net electrical power, electrical system efficiency, and electrical system exergy increase to a peak and then decrease. The main exergy destructions occur in the combustion chamber and the gas turbine.
Journal of Advanced Research in Fluid Mechanics and Thermal Sciences
Renewable energy used for refrigeration applications has become essential very recently due to th... more Renewable energy used for refrigeration applications has become essential very recently due to the fossil fuel crisis and the global warming problem. Moreover, using photovoltaic PV to generate electricity than using inverters and energy storage represents a high-cost process. This study aims to investigate the opportunity of using PV output directly to operate a refrigeration system. The absorption refrigeration system uses heat as an energy source for the generator that drives the system. Moreover, the absorption refrigeration system doesn't have a compressor but a generator. As a result, the novel aspect of this study is the use of PV electricity's DC output to power the heater that provides the needed heat for the generator without the use of an inverter that provides AC electricity. The essential very difference here is that the compressor needs a consistent and steady electric supply. However, using DC electricity for heating is not very restricted if the voltage fluct...
Sustainability
This study focused on exergo–conomic and parametric analysis for Taji station in Baghdad. This st... more This study focused on exergo–conomic and parametric analysis for Taji station in Baghdad. This station was chosen to reduce the emission of waste gases that pollute the environment, as it is located in a residential area, and to increase the production of electric power, since for a long time, Iraq has been a country that has suffered from a shortage of electricity. The main objective of this work is to integrate the Taji gas turbine’s power plant, which is in Baghdad, with the Rankine cycle and organic Rankine cycle to verify waste heat recovery to produce extra electricity and reduce emissions into the environment. Thermodynamic and exergoeconomic assessment of the combined Brayton cycle–Rankine cycle/Organic Rankin cycle (GSO CC) system, considering the three objective functions of the First- and Second-Law efficiencies and the total cost rates of the system, were applied. According to the findings, 258.2 MW of power is produced from the GSO CC system, whereas 167.3 MW of power i...
International Journal of Heat and Technology
Sustainability
The heat exchanger is crucial to all systems and applications that use it. Researchers are primar... more The heat exchanger is crucial to all systems and applications that use it. Researchers are primarily focused on improving this component’s thermal conductivity to improve its efficiency. This was achieved by using one or more of the following strategies: inserting tapes with various shapes and numbers, inserting rings of various shapes and spacing between each, and transforming a basic liquid into a nanoliquid by adding nanomaterials with high conductivity and ultra-small particle sizes. Different types of nanomaterials were added in varying concentrations. In earlier studies, it was found that every increase in heat transfer was accompanied by a pressure drop at both ends of the exchanger. The amount of heat transferred and the pressure drop are affected by many factors, such as the torsion tape ratio, the pitch of the ring, and whether the pitch faces the direction of flow or not. Heat transfer rates can also be impacted by factors such as the length and angle of the wings, how ma...
International Journal of Design & Nature and Ecodynamics, Dec 31, 2022
Processes
Enhancing the sustainability and diversification of Iraq’s electricity system is a strategic obje... more Enhancing the sustainability and diversification of Iraq’s electricity system is a strategic objective. Achieving this goal depends critically on increasing the use of renewable energy sources (RESs). The significance of developing solar-powered technologies becomes essential at this point. Iraq, similar to other places with high average direct normal irradiation, is a good location for concentrated solar thermal power (CSP) technology. This study aims to recover the waste heat from the gas turbine cycle (GTC) in the Al-Qayara power plant in Iraq and integrate it with a solar power tower. A thermoeconomic analysis has been done to support the installation of an integrated solar combined cycle (ISCC), which uses concentrated solar tower technology. The results indicate that the examined power plant has a total capacity of 561.5 MW, of which 130.4 MW is due to the waste heat recovery of G.T.s, and 68 MW. is from CSP. Due to the waste heat recovery of GTC, the thermal and exergy effici...
In this study, a system-level zero-dimensional model for planar solid oxide fuel cellgas turbine ... more In this study, a system-level zero-dimensional model for planar solid oxide fuel cellgas turbine (SOFC/GT) hybrid system has been studied to investigate the effect of diverse operating conditions such as operating pressure, air utilization factor (Ua), and fuel utilization factor (Uf) on the performance of a selected hybrid system. Moreover, the system’s power production and performance were discussed in two various configurations: anode-supported model (ASM) and electrolyte-supported model (ESM). This study’s models were implemented in Matlab® to calculate the optimum operating parameters and determine the hybrid system’s performance characteristics. According to the finding, a maximum of 717.8 kW power is produced at 7.7 bar pressure for the ASM. In contrast, a maximum of 630.3 kW power is produced at 12 bar pressure for ESM. The highest electrical system efficiencies for the ASM and the ESM are 62.32% and 56.23%, respectively. Cite this article as: Akroot A, Namli L,. Performance...
Proton electrolyte membrane fuel cells (PEMFC) are promising power sources for automotive applica... more Proton electrolyte membrane fuel cells (PEMFC) are promising power sources for automotive applications because of their high power density, low operation temperature (between 60℃ - 80℃), and lower environmental pollution. A proper water and thermal management are needed to keep the membrane humidified for high proton conductivity, durability for PEMFC materials, and to ensure the operation temperature of fuel cell stack remains under a tolerable limit.A general calculation methodology has been developed to provide information regarding the system power output, amount of water and heat products, and system efficiency, thereby assisting to achieve the best water and thermal management conditions.Polimer membran elektrolit (PEM) yakıt hücreleri yüksek güç yoğunlukları, düşük çalışma sıcaklıkları (60℃ - 80℃ arası) ve düşük çevresel kirlilikleri nedeniyle otomotiv uygulamaları için umut verici güç kaynaklarındandır. Membranı nemli tutarak yüksek proton iletkenliğini sağlamak, polimer membran elektrolit yakıt hücresi malzemelerinin dayanıklılığı ve yakıt hücresinin çalışma sıcaklığının kabul edilir sınırlar altında kalması için uygun su ve termal yönetim gerekmektedir.Sistemin güç çıktısı, üretilen su ve ısı miktarı ve sistem verimliliği ile ilgili olarak bilgi sağlamak; ve böylece en iyi su ve termal yönetim koşullarına ulaşmak amacıyla genel bir hesaplama yöntemi geliştirilmiştir
Journal of Science and Technology, 2021
This paper uses the CFD technique to simulate the internal environment of a hospital operating ro... more This paper uses the CFD technique to simulate the internal environment of a hospital operating room, including the surgical area that includes the patientand the surgical team. Moreover, this work provides mathematical simulation of many models to be placed in the air entry and air exit areas in the operating room to obtainthe optimal model of air distribution within the operating room. The results obtained matched well with experimental data from approved literature and standards. These results found that airflow and air velocity significantly affect the patient’s thermal comfort in the operating room.Besides, it is observed that some recirculation zone is formed, and this is a result of the heat generated by the surgical team and the accelerated air. This region is considered a source for the survival of the polluted air in the room. Keywords: CFD, Operating room, Numerical analysis.
Journal of Electrochemical Energy Conversion and Storage, 2020
In this study, two solid oxide fuel cell (SOFC) hybrid systems (anode-supported model (ASM) and e... more In this study, two solid oxide fuel cell (SOFC) hybrid systems (anode-supported model (ASM) and electrolyte-supported model (ESM)) is developed in matlab® and compared. The hybrid system model is considered to investigate the impacts of various operating parameters such as SOFC operating temperature and steam/carbon ratio on power production and performance of the hybrid system where it is projected that results can be utilized as guidelines for optimal hybrid system operation. According to the findings, a maximum 695 kW power is produced at 750 °C operating temperature for the anode-supported model, whereas 627 kW power is produced at 1000 °C for the electrolyte-supported model. The highest electrical efficiencies for the anode-supported model and the electrolyte-supported model are 64.6% and 58.3%, respectively. Besides, the lower value of the steam to carbon ratio is favorable for increased power output from the fuel cell and consequently a high SOFC efficiency.
International Journal of Green Energy, 2019
A system level, steady-state thermodynamics model for an automotive PEM fuel cell system was deve... more A system level, steady-state thermodynamics model for an automotive PEM fuel cell system was developed to investigate the effects of vehicle speed and operating pressure on the size of the system components, heat and water formation, fuel consumption, fuel cell, and system efficiency. Moreover, the consequences of the choices of membrane's thickness and ionic conductivity on thermal and system efficiencies as a function of vehicle speed are analyzed. The model consists of a PEM fuel cell stack model and supplementary models for all necessary auxiliary components. Results show that increasing the system pressure has a significant positive impact on the water balance characteristics of the system, since less water is needed to reach the required relative humidity levels for the reactants. On the other hand, the high-pressure system requires more power in order to operate the compressor, which in turn, decreases the system efficiency. Decreasing air stoichiometry at high operating pressures improves the water management but has no effect at low pressures. Results also show that increasing the membrane's ionic conductivity and decreasing its thickness enhances the system efficiency especially at higher vehicle speeds. Lastly, it is obtained that the system efficiency decreases as the vehicle speed increases.
International Journal of Trend in Scientific Research and Development, 2019
This article presents a steady-state thermodynamic model of a solid oxide fuel cell/gas turbine h... more This article presents a steady-state thermodynamic model of a solid oxide fuel cell/gas turbine hybrid cycle which developed by using a simulation software, MATLAB®. The hybrid model integrates a zero-dimensional level SOFC model with gas turbine. The hybrid system was used to study the effects of some operation parameter such as SOFC operating temperature, and current density on the specific work output, electrical efficiency, and exergy efficiency of a generic hybrid cycle. The results show that if the SOFC operating temperature, the power output, electrical efficiency, and exergy efficiency increase. The electrical efficiency of the hybrid system increase from 62% to 68%, and the exergy efficiency of the hybrid system increases from 60% to 66% when the operation temperature increases from 600°C to 750°C at a current density of 6000 A/cm2. On the other hand, the system efficiency and exergy decreases with an increase in the current density.
The International Journal of Engineering and Science (IJES), 2020
Energy and exergy analyses are introduced to a zero-dimensional hybrid system of solid oxide fuel... more Energy and exergy analyses are introduced to a zero-dimensional hybrid system of solid oxide fuel cell-gas turbine, for steady-state operation. The effects of two important SOFC parameters (operating pressure and current density) on varying conditions are examined. According to the obtained results, a decrease in SOFC current density improved the system performance (electrical efficiencies and exergy efficiencies) due, primarily, to the reduction in Ohmic losses, which results in a higher stack voltage. As system pressure increases, net electrical power, electrical system efficiency, and electrical system exergy increase to a peak and then decrease. The main exergy destructions occur in the combustion chamber and the gas turbine.