Sangseok Yu - Academia.edu (original) (raw)
Papers by Sangseok Yu
Energy Conversion and Management, Sep 1, 2023
Volume 6: Energy
A 50kW class PEMFC and 30kAh battery was evaluated to find a correlation between the stack net po... more A 50kW class PEMFC and 30kAh battery was evaluated to find a correlation between the stack net power overshoot and the stack temperature for sudden load change. First, a 50kW class PEMFC (Proton Exchange Membrane Fuel Cell) model and a battery model were designed and verified using experimental values. Sensitivity study of Energy Management system strategy was also carried out to find the optimal power ratio of the stack and the battery. Next, net power overshoot of the stack and the temperature data of the stack during a sudden load change were compared. The results show that the main factors affecting the Energy Management System strategy of the stack is the stack temperature.
Transactions of the Korean Hydrogen and New Energy Society
Transactions of the Korean Hydrogen and New Energy Society, 2021
Transaction of the Korean Society of Automotive Engineers, 2022
New & Renewable Energy, 2017
International Journal of Hydrogen Energy, 2022
Processes, 2020
In this study, transient responses of a polymer electrolyte fuel cell system were performed to un... more In this study, transient responses of a polymer electrolyte fuel cell system were performed to understand the effect of sensor fault signal on the temperature sensor of the stack and the coolant inlet. We designed a system-level fuel cell model including a thermal management system, and a controller to analyze the dynamic behavior of fuel cell system applied with variable sensor fault scenarios such as stuck, offset, and scaling. Under drastic load variations, transient behavior is affected by fault signals of the sensor. Especially, the net power of the faulty system is 45.9 kW. On the other hand, the net power of the fault free system is 46.1 kW. Therefore, the net power of a faulty system is about 0.2 kW lower than that of a fault-free system. This analysis can help in understanding the transient behavior of fuel cell systems at the system level under fault situations and provide a proper failure avoidance control strategy for the fuel cell system.
Transactions of the Korean Hydrogen and New Energy Society, 2021
ASME 2019 13th International Conference on Energy Sustainability, 2019
Efficient hydrogen flow control is of great importance to ensure the reliable operation of an aut... more Efficient hydrogen flow control is of great importance to ensure the reliable operation of an automotive fuel cell system because it is closely associated with the safety and the economic efficiency. In this study, an effective hydrogen flow control algorithm for hydrogen excess ratio control is addressed by pointing out the recovery speed and overshoot response. Unlike previous studies on the hydrogen management systems of an automotive fuel cell, this study presents an analytic hydrogen tank model which can present the characteristics of the discharge and charge of hydrogen from a type 4 hydrogen tank. To this end, a mode reference adaptive control (MRAC) based on proportional-integral (PI) control is introduced, to ensure robust hydrogen flow during the dynamic operation of fuel cell system. The MRAC was compared with the nominal PI control and PWM control in the hydrogen management system of an automotive fuel cell operating within normal conditions, under steady-state responses...
Energies, 2021
In a methanol-reforming system, because the mixture of methanol and water must be evaporated befo... more In a methanol-reforming system, because the mixture of methanol and water must be evaporated before reaching the reforming reaction zone, having an appropriate evaporator design is a fundamental requirement for completing the reforming reaction. This study investigates the effect of the evaporator design for the stable reforming of methanol–water mixtures. Four types of evaporator are compared at the same heat duty of the methanol-reforming system. The four evaporators are planar heat exchangers containing a microchannel structure, cylindrical shell-and-tube evaporators, zirconia balls for internal evaporation, and combinations of cylindrical shell-tubes and zirconia balls. The results show that the evaporator configuration is critical in performing stable reform reactions, especially for the flow-field mode of the evaporator. Additionally, the combination of both internal and external evaporation methods generates the highest performance for the methanol-reforming system, with the ...
International Journal of Hydrogen Energy, 2021
A fuel cell air independent propulsion (AIP) system of underwater vehicle requires a hydrogen sto... more A fuel cell air independent propulsion (AIP) system of underwater vehicle requires a hydrogen storage system. The methanol steam reforming system is a candidate of hydrogen storage which can produce hydrogen from chemical reaction. Different from reforming system for station fuel cell system, the methanol steam reformer (MSR) for underwater vehicle requires high-pressure operation. Since the longitudinal temperature uniformity is a core parameter of conversion efficiency of steam reforming system, this study is focused on computational analysis of phase change heat transfer through the annulus for methanol steam reforming reaction. The annulus MSR using phase change material was developed to improve the temperature uniformity. The simulation model is verified with safety and performance analysis code (SPACE). The performance parameters of MSR were flow arrangement, steam to carbon ratio (SCR), and gas hourly space velocity (GHSV). The results were analyzed in terms of the hydrogen y...
Energy Conversion and Management, Sep 1, 2023
Volume 6: Energy
A 50kW class PEMFC and 30kAh battery was evaluated to find a correlation between the stack net po... more A 50kW class PEMFC and 30kAh battery was evaluated to find a correlation between the stack net power overshoot and the stack temperature for sudden load change. First, a 50kW class PEMFC (Proton Exchange Membrane Fuel Cell) model and a battery model were designed and verified using experimental values. Sensitivity study of Energy Management system strategy was also carried out to find the optimal power ratio of the stack and the battery. Next, net power overshoot of the stack and the temperature data of the stack during a sudden load change were compared. The results show that the main factors affecting the Energy Management System strategy of the stack is the stack temperature.
Transactions of the Korean Hydrogen and New Energy Society
Transactions of the Korean Hydrogen and New Energy Society, 2021
Transaction of the Korean Society of Automotive Engineers, 2022
New & Renewable Energy, 2017
International Journal of Hydrogen Energy, 2022
Processes, 2020
In this study, transient responses of a polymer electrolyte fuel cell system were performed to un... more In this study, transient responses of a polymer electrolyte fuel cell system were performed to understand the effect of sensor fault signal on the temperature sensor of the stack and the coolant inlet. We designed a system-level fuel cell model including a thermal management system, and a controller to analyze the dynamic behavior of fuel cell system applied with variable sensor fault scenarios such as stuck, offset, and scaling. Under drastic load variations, transient behavior is affected by fault signals of the sensor. Especially, the net power of the faulty system is 45.9 kW. On the other hand, the net power of the fault free system is 46.1 kW. Therefore, the net power of a faulty system is about 0.2 kW lower than that of a fault-free system. This analysis can help in understanding the transient behavior of fuel cell systems at the system level under fault situations and provide a proper failure avoidance control strategy for the fuel cell system.
Transactions of the Korean Hydrogen and New Energy Society, 2021
ASME 2019 13th International Conference on Energy Sustainability, 2019
Efficient hydrogen flow control is of great importance to ensure the reliable operation of an aut... more Efficient hydrogen flow control is of great importance to ensure the reliable operation of an automotive fuel cell system because it is closely associated with the safety and the economic efficiency. In this study, an effective hydrogen flow control algorithm for hydrogen excess ratio control is addressed by pointing out the recovery speed and overshoot response. Unlike previous studies on the hydrogen management systems of an automotive fuel cell, this study presents an analytic hydrogen tank model which can present the characteristics of the discharge and charge of hydrogen from a type 4 hydrogen tank. To this end, a mode reference adaptive control (MRAC) based on proportional-integral (PI) control is introduced, to ensure robust hydrogen flow during the dynamic operation of fuel cell system. The MRAC was compared with the nominal PI control and PWM control in the hydrogen management system of an automotive fuel cell operating within normal conditions, under steady-state responses...
Energies, 2021
In a methanol-reforming system, because the mixture of methanol and water must be evaporated befo... more In a methanol-reforming system, because the mixture of methanol and water must be evaporated before reaching the reforming reaction zone, having an appropriate evaporator design is a fundamental requirement for completing the reforming reaction. This study investigates the effect of the evaporator design for the stable reforming of methanol–water mixtures. Four types of evaporator are compared at the same heat duty of the methanol-reforming system. The four evaporators are planar heat exchangers containing a microchannel structure, cylindrical shell-and-tube evaporators, zirconia balls for internal evaporation, and combinations of cylindrical shell-tubes and zirconia balls. The results show that the evaporator configuration is critical in performing stable reform reactions, especially for the flow-field mode of the evaporator. Additionally, the combination of both internal and external evaporation methods generates the highest performance for the methanol-reforming system, with the ...
International Journal of Hydrogen Energy, 2021
A fuel cell air independent propulsion (AIP) system of underwater vehicle requires a hydrogen sto... more A fuel cell air independent propulsion (AIP) system of underwater vehicle requires a hydrogen storage system. The methanol steam reforming system is a candidate of hydrogen storage which can produce hydrogen from chemical reaction. Different from reforming system for station fuel cell system, the methanol steam reformer (MSR) for underwater vehicle requires high-pressure operation. Since the longitudinal temperature uniformity is a core parameter of conversion efficiency of steam reforming system, this study is focused on computational analysis of phase change heat transfer through the annulus for methanol steam reforming reaction. The annulus MSR using phase change material was developed to improve the temperature uniformity. The simulation model is verified with safety and performance analysis code (SPACE). The performance parameters of MSR were flow arrangement, steam to carbon ratio (SCR), and gas hourly space velocity (GHSV). The results were analyzed in terms of the hydrogen y...