• 한국신재생에너지학회:학술대회논문집
• /
• 2008.10a
• /
• pp.10-13
• /
• 2008

Fuel cell systems have witnessed remarkable development in recent years as they offer a clean and efficient alternative for power generation. Testing was conducted to determine the safety performance of a residential fuel cell system when subjected to abnormal operation condition, especially for voltage sag and fuel cut. In case of voltage sag to 198V, its arriving time at rated power had shown a slight lag but there wasn't any noticeable change when operating it between rated voltage(220V) and 10% voltage sag(198V). In case of fuel cut, it also showed stable shut-down characteristics. The test results are being used to develop a new safety evaluation for residential fuel cell system.

• Journal of Electrochemical Science and Technology
• /
• v.5 no.3
• /
• pp.73-81
• /
• 2014

This paper describes the continuous flow operation of membraneless sodium perborate fuel cell using acid/alkaline bipolar electrolyte. Here, hydrazine is used as a fuel and sodium perborate is used as an oxidant under Alkaline-acid media configuration. Sodium perborate affords hydrogen peroxide in aqueous medium. In our operation, the laminar flow based microfluidic membranleless fuel cell achieved a maximum power density of $27.2mW\;cm^{-2}$ when using alkaline hydrazine as the anolyte and acidic perborate as the catholyte at room temperature with a fuel mixture flow rate of $0.3mL\;min^{-1}$. The simple planar structured membraneless sodium perborate fuel cell enables high design flexibility and easy integration of the microscale fuel cell into actual microfluidic systems and portable power applications.

• New & Renewable Energy
• /
• v.4 no.2
• /
• pp.45-51
• /
• 2008

The fuel cell system is environment-friendly and energy efficient system. Especially, the fuel cell cogeneration systems providing heat and electricity to buildings have been developed and applied to a lot of sites in the world to cope with the global warming and $CO_2$ emission problem. This paper presents the result of study on the economic evaluation with super-micro fuel cell (SMFC) cogeneration system by varying the floor area ($132m^2{\sim}331m^2$) of the house, whose system capacity ranges from 0.10 kWe to 0.50 kWe. The electricity demand, heat demand, saved energy cost, and the simple pay-back period have been simulated for the various capacities of fuel cell cogeneration system. As a result, this study suggests the fuel cell system’s capacity decision strategy for a given house area. Contrary to conventional design assumptions, the smaller capacity fuel cell cogeneration system is appropriate for the house of large floor area to defense the progressive electricity tax, and the larger capacity fuel cell cogeneration system is appropriate for the house of small floor area to sell the electricity.

• 한국신재생에너지학회:학술대회논문집
• /
• 2008.05a
• /
• pp.25-28
• /
• 2008

The fuel cell system is environment-friendly and energy efficient system. Especially, the fuel cell cogeneration systems providing heat and electricity to buildings have been developed and applied to a lot of sites in the world to cope with the global warming and $CO_2$ emission problem. This paper presents the result of study on the economic evaluation with super-micro fuel cell (SMFC) cogeneration system by varying the floor area ($132m^2{\sim}331m^2$) of the house, whose system capacity ranges from 0.10 kWe to 0.50 kWe. The electricity demand, heat demand, saved energy cost, and the simple pay-back period have been simulated for the various capacities of fuel cell cogeneration system. As a result, this study suggests the fuel cell system's capacity decision strategy for a given house area. Contrary to conventional design assumptions, the smaller capacity fuel cell cogeneration system is appropriate for the house of large floor area to defense the progressive electricity tax, and the larger capacity fuel cell cogeneration system is appropriate for the house of small floor area to sell the electricity.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.24 no.4
• /
• pp.418-425
• /
• 2021

Submarines are weapons systems that have been proven to be useful in battle since World War I and have continued to improve the efficiency of propulsion systems in order to be used efficiently on the battlefield. In particular, countries that unable to utilize nuclear propulsion systems make efforts to increase the efficiency of Air Independent Propulsion systems, and typical examples are fuel cells, Stirling engines and MESMA. It is also expected that the development of new propulsion systems such as hydrogen-reformer fuel cells, metal-air fuel cell and direct combustion propulsion systems will continue, so the characteristics of these will be examined and the performance based on the published data be checked in this thesis.

• Proceedings of the KAIS Fall Conference
• /
• 2002.11a
• /
• pp.141-144
• /
• 2002

Recently, the operation of power distribution systems has become more difficult because the peak demand load is increasing continuously and the daily load factor is getting worse and worse. Also, the consideration of deregulation and global environment in electric power industry is required. In order to overcome these problems, a study on the planning and operation in distribution systems of dispersed generating sources such as fuel cell systems, photovoltaic systems and wind power systems has been performed energetically. This study presents a method for determining an optimal operation strategy of dispersed co-generating sources, especially fuel cell systems, in the case of both only electric power supply and thermal supply as well as electric power supply. In other words, the optimal operation of these sources can be determined easily by the principle of equal incremental fuel cost and the thermal merits is evaluated quantitatively through Kuhn-Tucker's optimal conditions. In order to select the optimal locations of those sources, an priority method using the comparison of total cost at the peak load time interval is also presented. The validity of the proposed algorithms is demonstrated using a model system.

• 한국신재생에너지학회:학술대회논문집
• /
• 2010.11a
• /
• pp.90.1-90.1
• /
• 2010

The design and fabrication of a metallic bipolar plate-gasket assembly for polymer electrolyte fuel cells (PEMFCs) is defined. This bipolar plate-gasket assembly was prepared by inserting a previously prepared bipolar plate in the specially designed gasket mold. For this aim, a proprietary fluoro-silicone based rubber was injected directly into the bipolar plate borders. Gaskets obtained like this showed the chemically / physically stable and the good sealibilty in typically operating PEM fuel cell conditions. And also, this bipolar plate-gasket assembly shows lots of advantages with respect to traditional PEMFCs stack assembling systems: useful application to automative stacking due to easy handling, reduced fabrication time, possibility of quality control and failed elements substitution. This bipolar plate-gasket assembly was evaluated in the short fuel cell stack and met the leakage requirement for normal operation both in short-term and in long-term operation. Especially, it was confirmed that this gasket could be applied successfully even in the high pressure FEM fuel cell systems(over 2.0 bar in absolute pressure).

• Transactions of the Korean hydrogen and new energy society
• /
• v.26 no.2
• /
• pp.136-147
• /
• 2015

Dead-ended operation of Proton Exchange Membrane Fuel Cell(PEMFC) provides the simplification of fuel cell systems to reduce fuel consumption and weight of fuel cell. However, the water accumulation within the channel prohibits a uniform supply of fuel. Optimization of the purge strategy is required to increase the fuel cell efficiency since fuel and water are removed during the purge process. In this study, we investigated the average voltage output which depends on two interrelated conditions, namely, the supply gas pressure, purging valve open time. In addition, flow visualization was performed to better understand the water build-up on the anode side and cathode side of PEMFC in terms of a variety of the current density. We analyzed the correlation between the purge condition and water flooding.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.19 no.7
• /
• pp.736-745
• /
• 2009

Fuel cells convert a fuel together with oxygen in a highly efficient electrochemical reaction to electricity and water. Since the electrochemical reaction in the fuel cell stack dose not generate any noise, Fuel cell systems are expected to operated much quieter than combustion engines. However, the tonal noise and the broad band noise caused by a centrifugal compressor and an electric motor cause which is required to feed the ambient air to the cathode of the fuel cell stack with high pressure. In this study, the multi-camber perforated muffler is used to reduce noise. We propose optimized muffler model using an axiomatic design method that optimizes the parameters of perforated muffler while keeping the volume of muffler minimized.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.1012-1015
• /
• 1996

This study focuses on the optimal operation and control strategy of the fuel cell process. The control objective of the Phosphoric Acid Fuel Cell (PAFC) is established and dynamic modeling equations of the entire fuel cell process are formulated as discrete-time type. On-line optimal control of the MIMO system employs the direct decomposition-coordination method. The objective function is modified as the tracking form to enhance the response capability to the load change. The weight factor matrices Q,R, which are design parameters, are readjusted. This control system is compared with LQI method and the results show that the suggested method is better than the traditional method in pressure difference control.