• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.137-141
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• 2007

The startup behaviour of PEM fuel cells at subfreeze zero is one of the most challenging tasks to be solved before PEM fuel cell vehicle is commercialized. Automotive companies are trying to increase cold statup capability of fuel cell. In this study, we found out the design factor of the stack to increase cold startup capability using 4kW stack and then cold startup test was performed at the various shutdown condition and the various current. In order to test the cold startup possibility and capability in vehicle, we installed 80kW stack in the vehicle and this 80kW fuel cell vehicle was housed in an environmental chamber to investigate the characteristics of cold startup and driving. We found that it is possible for fuel cell vehicle with 80kW stack to self-heated cold startup and drive at $-15^{\circ}C$.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.47-50
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• 2008

The sub-zero cold is a major environmental consideration for the operational readiness of FCEVs because fuel cells produce water and utilize wet air with varying water content to generate electricity. Typical fuel cells thus have a fatal flaw in freezing conditions at startup. This drawback becomes more serious with the outsourced fuel cell that is entirely water-based for its internal humidification. In this background, the HMC's self-designed fuel cell was developed as an alternative and was employed in the Tucson-based FCEV in 2006 demonstrating its good cold-startup characteristics. The cold-startup capacity of the vehicle was validated through tests in the cold chamber and on the road, resulting in 50% stack power achieved in 250 seconds at $-15^{\circ}C$.

• Aerospace Engineering and Technology
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• v.8 no.2
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• pp.19-25
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• 2009

This paper includes test results of 30tonf-level TP+GG startup simulation cold flow test using liquid oxygen and kerosene. Test objectives, coupled test plant configuration, test condition, test procedure of performed tests, and test results are presented.

• Proceedings of the Korea Society for Simulation Conference
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• 2002.05a
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• pp.203-207
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• 2002

The dynamic analysis is performed for cold, warm, and hot startups and shutdown. The operating characteristics of an horizontal drum type HRSG are analyzed as well. This analysis was performed by ProTRAX which is a commercial software developed by TRAX Corp.

• Transactions of the Korean hydrogen and new energy society
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• v.20 no.3
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• pp.224-231
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• 2009

The improvement of cold start capability is one of the most challenging tasks to be solved for commercialization of fuel cell vehicle. In this study, cold start test and ice blocking test(IBT) of fuel cell stack were carried out under various operating conditions. This fuel cell stack can be thawed from -20$^{\circ}$C within 25s and the voltage change was found to be comprised of 4 steps; the first step is the voltage decrease by overpotential, the second step is the voltage increase by the cell temperature increase, the third step is the voltage decrease by ice blocking, and the last step is the voltage increase by thawing. Bootstrap startup was failed after shutdown at temperature under 40$^{\circ}$C because of much condensed water in the fuel cell. Quantitative estimation of cold start capability have been demonstrated by ice blocking test(IBT). In the results, it was found that cold start capability was improved double every 10$^{\circ}$C from 30$^{\circ}$C to 65$^{\circ}$C and enhanced by 30% at the condition of SR 3/4 compared to SR 1.5/2.0 and enhanced by 20% with dry purge condition compared to with RH 50% purge condition.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.2
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• pp.93-102
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• 2016

An experimental study has been conducted to verify the startup characteristic of a Center Body Diffuser (CBD) for simulating a low pressure environment when at high altitudes. Vacuum chamber pressure and startup characteristics of the CBD were investigated according to various geometries of the center body structure by a cold gas flow test. The test results show that the startup pressure is lowest when the center body contraction angle is approximately $15^{\circ}$. The startup characteristic of the CBDs significantly improves when the diffuser inlet length ($L_d/D_d$) is decreasing and the divergence length ($L_s$) is increasing. Additionally, it is possible to simulate various high altitude, low pressure conditions for various rocket engines that have different nozzle expansion ratios by adjusting the center body's position inside the diffuser.

• Aerospace Engineering and Technology
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• v.7 no.2
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• pp.170-175
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• 2008

In this study, it was investigated that the characteristics of startup and compatibility using several type hot and cold gases. The characteristics of starting LRE by pyro starter was compared with that by a Helium spinner. The compatibility of pyro gas, a gaseous Helium, Hydrogen+Nitrogen mixture gas, and air was investigated by a simple 1D turbine analysis considered the properties of each gas and turbine efficiency. Most of them were compatible to start up the LRE however air was properly used only for low power mode of turbine.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.216-220
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• 2006

In this study, it was investigated that the characteristics of startup and compatibility using several type hot and cold gases. The characteristics of starting LRE by pyro starter was compared with that by a He spinner. The compatibility of pyre gas, a gaseous He, H2+N2 mixture gas, and air was investigated by a simple 1D turbine analysis considered the properties of each gases and turbine efficiency. Most of them were compatible to start up the LRE but air was properly used only when the turbine was low power mode.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.412-414
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• 2009

In recent times, starting up polymer electrolyte membrane fuel cells(PEMFC) in sub-zero condition is a great challenge of fuel cell electric vehicle(FCEV). The water produced in a cathode during PEMFCs operate. The water changes into the form of solid/ice in sub-zero temperatures and this makes trouble in PEMFC cells. Voltage of PEMFC drops and cold startup is failed. This paper describes an experimental study on the effect of thermal cycle to degradation of MEA in PEMFC.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.33-36
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• 2008

Cell degradation when anode channels are blocked during cold start up was tested and measured. Proton exchange membrane fuel cell (PEMFC) stacks with several configurations of channel blockages were operated and decay in performance was analyzed. When only channels near hydrogen inlet were blocked, performance was rarely changed. In contrast, significant cell reversal occurred and considerable amount of $CO_2$ was produced when all channels near inlet and outlet were blocked. In the case, it was also observed that performance was severely decreased in the area where hydrogen was not supplied sufficiently.