Browsing by Author "Chung, Chen-Chung"

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Development of an air bleeding technique and specific duration to improve the CO tolerance of proton-exchange membrane fuel cells
(2009-08-01)
Chung, Chen-Chung
;
Chen, Chiun-Hsun
;
Weng, De-Zheng
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機械工程學系
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Department of Mechanical Engineering
This study investigated transient CO poisoning of a proton-exchange membrane fuel cell under either a fixed cell voltage or fixed current density. During CO poisoning tests, the cell performance decreases over time. Experiments were performed to identify which method yields better performance in CO poisoning tests. The results revealed that a change in cell voltage did not affect the stable polarization behavior after CO poisoning of the cell. On the other hand, a higher fixed current density yielded better tolerance of 52.7 ppm CO. The air bleeding technique was then applied using different timings for air introduction during CO poisoning tests. Air bleeding significantly improved the CO tolerance of the cell and recovered the performance after poisoning, regardless of the timing of air introduction. The effects of different anode catalyst materials on cell performance were also investigated during poisoning tests. Without air bleeding, a Pt-Ru alloy catalyst exhibited better CO tolerance than a pure Pt catalyst. However, the air bleeding technique can effectively increase the CO tolerance of cells regardless of the type of catalyst used. (C) 2009 Elsevier Ltd. All rights reserved.
Experimental and numerical studies of micro PEM fuel cell
(2011-10-01)
Peng, Rong-Gui
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Chung, Chen-Chung
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Chen, Chiun-Hsun
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機械工程學系
;
Department of Mechanical Engineering
A single micro proton exchange membrane fuel cell (PEMFC) has been produced using Micro-electro-mechanical systems (MEMS) technology with the active area of 2.5 cm(2) and channel depth of about 500 mu m. A theoretical analysis is performed in this study for a novel MEMS-based design of a micro PEMFC. The model consists of the conservation equations of mass, momentum, species and electric current in a fully integrated finite-volume solver using the CFD-ACE+ commercial code. The polarization curves of simulation are well correlated with experimental data. Three-dimensional simulations are carried out to treat prediction and analysis of micro PEMFC temperature, current density and water distributions in two different fuel flow rates (15 cm(3)/min and 40 cm(3)/min). Simulation results show that temperature distribution within the micro PEMFC is affected by water distribution in the membrane and indicate that low and uniform temperature distribution in the membrane at low fuel flow rates leads to increased membrane water distribution and obtains superior micro PEMFC current density distribution under 0.4V operating voltage. Model predictions are well within those known for experimental mechanism phenomena.
Improvement of CO tolerance of proton exchange membrane fuel cell (PEMFC) by an air-bleeding technique
(2005)
Chung, Chen-Chung
;
Chen, Chiun-Hsun
;
Lin, Hsiang-Hui
;
Yan, Yi-Yie
;
機械工程學系
The investigation studies improving PEMFC carbon monoxide by a periodic air dosing. The carbon monoxide in the fuel gas leads to a significant loss in power density due to CO poisoning in the anode. The method involves bleeding air into the anode fuel stream (H-2-CO), which contains CO in various concentrations (20, 52.7, 100 ppm). In the transient CO poisoning test, air-bleeding is performed for four different periodic air dosing and cell voltage is fixed at 0.6 V. The result of a dosing of air during 10 sec in intervals of 10 sec is similar to that of continuous air-bleeding except 100 ppm CO. The CO tolerance of the fuel cell and cell performance recovery from poisoning can be improved by air-bleeding.
Improvement of CO tolerance of proton exchange membrane fuel cell by an air-bleeding technique
(2008-02-01)
Chen, Chiun-Hsun
;
Chung, Chen-Chung
;
Lin, Hsiang-Hui
;
Yan, Yi-Yie
;
機械工程學系
This study investigates the improvement of proton exchange membrane fuel cell (PEMFC) carbon monoxide by periodic air dosing. The carbon monoxide in the fuel gas leads to a significant loss in power. density due to CO poisoning in the anode. The method involves bleeding air into the anode fuel stream (H(2)-CO), which contains CO in various concentrations (20 ppm, 52.7 ppm, and 100 ppm). In the transient CO poisoning test, air bleeding is performed for four different periodic air dosing and cell voltage is fixed at 0.6 V. The result of a dosing of air for 10 s in intervals of 10 s is similar to that of continuous air bleeding except for 100 ppm CO. The CO tolerance of the fuel cell and cell performance recovery from poisoning can be improved by air bleeding.
Investigation of cell operation conditions for co tolerance improvement of PEMFC
(2007-12-01)
Chung, Chen-Chung
;
Chen, Chiun-Hsun
;
Weng, Der-Cheng
;
Yan, Yi-Yie
;
Lin, Hsiang-Hui
The investigation is to experimentally study the transient CO poisoning test with different cell operation conditions. One is fixing the cell voltage and the other is fixing the current density. In the former condition, the voltages are fixed at 0.5, 0.6, 0.7V, respectively, whereas the current densities are fixed at 600, 1000, 1200mA/cm(2), respectively, in the latter one. In the transient poisoning test, the cell performance will be declined with time. The poisoned polarization curves are determined as soon as the performance subjected to CO poisoning reaches a steady state. Then, it will determine which one has a better performance in CO poisoning test and find out the difference between these two methods. With fixed cell voltage to perform transient CO poisoning test, it indicates that changing cell voltage cannot transform the stable poisoned polarization behaviors, whereas with fixed current density, it can get a better recovery performance at a fixed CO concentration (52.7ppm).