• Journal of the Korean Society of Safety
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• v.37 no.6
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• pp.158-165
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• 2022

Eco-friendly policies proposed by the government of The Republic of Korea have encouraged the use of eco-friendly vehicles. Hydrogen vehicles have exhibited the highest growth rate, although the current number of registered vehicles is low. In hydrogen vehicles, a thermally activated pressure relief device (TPRD) is installed to prevent explosions in the hydrogen gas cylinder. When discharged due to low ignition energy, hydrogen gas readily forms a jet flame. The risks induced by such jet flames were analyzed through a numerical analysis. Jet flames can activate TPRDs installed in nearby hydrogen gas cylinders. As a result, high-voltage cables exposed in the lower area of a vehicle can ignite within seconds. There was a 9.5-kW/m2 area around the vehicle (which can result in casualties) at a distance of ~5 m from the hydrogen gas cylinder, and a 37.5-kW/m2 area (which can cause significant damage) in the form of an inverted triangle toward the lower section of the vehicle. We believe that the risk factors analyzed herein should be considered for addressing accidents in hydrogen vehicles.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.5
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• pp.1068-1072
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• 2011

Hydrogen Fuel Cell Vehicle(HFCV) is system that uses electrical energy of fuel cell stack to main power source, which is different system with other vehicles that use high-voltage, large-current. Isolation performance of this system which is connected with electrical fire and electrical shock is important point. Isolation resistance of electric installation is divided according to working voltage, it follows criterion more than $100{\Omega}$/VDC (or $500{\Omega}$/VAC) about system operation voltage in a hydrogen fuel cell vehicle. Although measurement of isolation resistance in a hydrogen fuel cell vehicle is two methods, it uses mainly measurement by megger. However, the present isolation resistance measurement system that is optimized to use in electrical facilities is unsuitable for isolation performance estimation of a hydrogen fuel cell vehicle because of limit of maximum short current and difference of measurement resolution. Therefore, this research developed the isolation resistance measurement system so that may be suitable in isolation performance estimation of a hydrogen fuel cell vehicle, verified isolation performance about known resistance by performance verification of laboratory level about developed system, and executed performance verification through comparing results of developed system by performance verification of vehicle level with ones of existing megger. Developed system is judged to aid estimation and upgrade of isolation performance in a hydrogen fuel cell vehicle hereafter.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.579-582
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• 2008

PEM Fuel cell system was designed and constructed to use as a power source of unmanned aerial vehicles(UAV) in the present study. Sodium borohydride was selected as a hydrogen source and was decomposed by catalytic hydrolysis reaction. Fuel cell system consists of a fuel cell stack, a hydrogen generation system(HGS), and power management system(PMS). HGS was composed of a catalytic reactor, micropump, fuel cartridge, and separator. Hybrid power system between lithium-polymer battery and fuel cell was developed. The fuel cell system was integrated and packaged into a blended wing-body UAV. Energy density of the total system was 1,000 $W{\cdot}hr/kg$ and high endurance more than 5 hours was accomplished in the ground tests.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.1
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• pp.47-60
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• 2021

Hydrogen is a next-generation energy source, and according to the roadmap for activating the hydrogen economy, it is expected that industries to stably produce, store, and transport of hydrogen as well as the supply of hydrogen fuel cell vehicles will be made rapidly. Accordingly, safety measures for accidents of hydrogen vehicles in confined spaces such as tunnels are required. In this study, as part of a study to ensure the safety of hydrogen fuel cell vehicles in road tunnels, a basic investigation and research on the risk of fire and explosion due to gas leakage and hydrogen tank rupture among various hazards caused by hydrogen fuel cell vehicle accidents in tunnels was conducted. The following results were obtained. In the event of hydrogen fuel cell vehicle accidents, the gas release rate depends on the orifice diameter of TPRD, and when the gas is ignited, the maximum heat release rate reaches 3.22~51.36 MW (orifice diameter: 1~4 mm) depending on the orifice diameter but the duration times are short. Therefore, it was analyzed that there was little increase in risk due to fire. As the overpressure of the gas explosion was calculated by the equivalent TNT method, in the case of yield of VCE of 0.2 is applied, the safety threshold distance is analyzed to be about 35 m, and number of the equivalent fatalities are conservatively predicted to reach tens of people.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.4
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• pp.284-292
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• 2022

Hydrogen is promising a candidate for energy supporting the carbon neutrality policy for greenhouse gas reduction, which is being promoted in several countries, including Korea. Although challenging efforts-such as lowering the costs of green hydrogen production and fuel cells-remain, hydrogen fuel cell electric vehicles (FCEVs) are expected to play a significant role in the energy transition from fossil fuels to renewable energy. In line with this objective, the hydrogen FCEV working group in the International Organization for Standardization (ISO) compiled and revised international standards related to hydrogen refueling stations as of 2019. A well-established hydrogen quality management system based on the standard documents will increase the reliability of hydrogen charging stations and accelerate the use of FCEVs. In this study, among the published ISO standards and other references, the main requirements for managing charging stations and developing related techniques were summarized and explained. To respond preemptively to the growing FCEV market, a continuous hydrogen quality monitoring method suitable for use at hydrogen charging stations was proposed.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.5
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• pp.490-496
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• 2023

Unmanned aerial vehicles (UAVs) research is recently actively underway. Especially, fuel cell battery hybrid systems are widely used to overcome the limitations of continuous operation. However, fuel cell systems must be operated in combination with a battery due to their low specific output characteristics. Therefore, a hybrid power system model for UAVs is developed. The rule-based strategy is applied to the model to properly distribute power to batteries and fuel cells. As a result, the designed rule-based power distribution control operates UAVs while maintaining battery state of charge(SOC) at an appropriate level.

• Transactions of the Korean hydrogen and new energy society
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• v.35 no.1
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• pp.56-65
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• 2024

Fuel cell powered unmanned aerial vehicles (UAV) are globally being developed for various application according to hydrogen roadmap. However, safety standards for hydrogen fuel cell for UAV have not been established. Therefore, in this study, we derive safety data based on risk assessment to develop safety standards for fuel cells for UAV. We use fault tree analysis method which is broadly used in hydrogen facilities as a risk assessment tool. We set hydrogen leaks and fires as top events and derived the basic events. Safety data for the basic events were derived by quoting overseas safety standards related to fuel cells. The safety data will be used for developing fuel cell inspection standard according to Act on Hydrogen Economy Promotion and Hydrogen Safety Management.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.13-16
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• 2007

Fuel cell was used as a propulsion system for unmanned aerial vehicles (UAV) in the present study. Fuel cell propulsion system are an ideal alternative power source with high energy density for high-endurance UAV. Fuel cell power system provides UAV up to five times the energy densiη of existing batteries. Sodium borohydride, stored in liquid state, was selected as a hydrogen source. Hydrogen generation system consists of catalytic reactor, pump, fuel cartridge, and separator. Hybrid power management system (PMS) between fuel cell and lithium-polymer ba야ery was developed. Motor, pump, and fans， operated on battery power controlled by feedback signals of fuel cell system. Battery was recharged by surpuls powr of fuel cell.

• Transactions of the Korean hydrogen and new energy society
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• v.13 no.4
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• pp.330-338
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• 2002

A long-term energy system in the future is expected to be based on the ideal circulation system between water and hydrogen in the sense that the hydrogen prepared from water eventually returns to water again after its use. Currently, with respect to the hydrogen energy system, it is predicted that the turning-point at which the production cost of hydrogen will become to be lower than that of fossil fuels would be after 2010. However, fuel cell technology would be able to be practically used for the applications to the transportation vehicles and small-scale power sources from 2004, and therefore, an efficient construction of the infrastructure covering hydrogen production and supply systems would be required with short-/mid-term technologies for the $CO_2$ reduction associated with fossil fuel utilization. In this paper, the hydrogen quantity available in domestic market has been estimated focusing on the hydrogen by-produced from domestic industries, and also the infrastructure for hydrogen-driven vehicles like fuel cell cars has been reviewed.

• Journal of Auto-vehicle Safety Association
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• v.13 no.4
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• pp.73-80
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• 2021

Recently, Korea has established a plan for the supply of hydrogen vehicles and is promoting the expansion of the supply. Risk factors for hydrogen vehicles are hydrogen leakage, jet fire, and explosion. Therefore Safety measures are necessary for this hazard. In addition, risks in semi-closed spaces such as tunnels, underground roads, and underground parking lots should be analyzed. In this study, an explosion experiment was conducted on a hydrogen tank used in a hydrogen vehicle to analyze the risk of a hydrogen vehicle explosion accident that may occur in a semi-closed space. As results, the effect on the structure and the human body was analyzed using the overpressure and impulse values for each distance generated during the explosion.