In this study, we aim to develop a self-humidifying polymer electrolyte membrane fuel cell (PEMFC) by depositing platinum (Pt) on a membrane using sputtering. After we coated it with a Nafion^® ionomer solution. This is considered a solution that can prevent membrane degradation in low humidity conditions. By introducing this self-humidifying concept, we can expect improved performance compared to conventional PEMFCs. By managing the water content of Nafion^®, we aim to improve both the stability and performance of the PEMFCs. This research contributes to the development of more efficient and reliable PEMFC systems, showing promise for advances in this field.

Movable weir is a major system used to manage water level in a river to secure drinking water, agricultural water, and industrial water. It is critical to safely construct and operate movable weir, in any environmental circumstances. In this study, we performed an unsteady flow analysis, on the movable weir with overflow water depth. The continuity equation, with constant density and incompressible Navier-Stokes equation, were used for the flow analysis. The CFD results were applied for structural analysis, to evaluate the safety of movable weir. According to the analysis results, the movable weir has secured sufficient safety.

A method for thermoplastic fusion bonding was introduced using a commercial pressure cooker as a thermal bonding chamber to apply heat and pressure for polymer thermal bonding. The chamber pressure was controlled by simply modifying the regulator weight, which decided the boiling point of water in the chamber. In this experiment, Poly-Methyl Methacrylate (PMMA) was thermally bonded using the proposed technique. For PMMA thermal bonding, 52 grams of regulator weight was well matched for 26.2 kPa of chamber pressure. The corresponding boiling temperature of water to the pressure was 105.5℃, which was the glass transitional temperature of PMMA. The thermal bonding system demonstrated bonding between the PMMA sheet and PMMA film without deformation of the microchannel. The bonding strength was characterized at 195.5±1 N.

This paper reports the effectiveness of the introduction of NGDG-SOFC (Natural Gas-Fueled Distributed Generation Solid Oxide Fuel Cell) as a solution to social problems that could arise in the unification era due to the power shortage in North Korea. Under the actual operating conditions of the plant, a stack that operates at a voltage of 33.87 V and current of 31.24 A was modeled with a gross output of 1.06 kW and a net output of 1.00 kW considering the balance of plant (BOP) consumption power. Considering the average primary energy consumption in the ASEAN countries in 2020, 2,870 MW was estimated as the amount of power generation required in North Korea. Also, the gross area of the plant and the annual fuel cost were estimated. Consequently, it is concluded that the area of 861 km2 which corresponds to 0.71 percent of the gross area of North Korea, and fuel cost of about 1,474 million $/year are required. The introduction of NGDG-SOFC plants is believed to follow the global trend of renewable energy and resolving the power shortage in North Korea in an eco-friendly manner.

This study reports on the feasibility of applying polymer electrolyte membrane fuel cells (PEMFCs) system to an energy storage system (ESS). We modeled each constituting system to compute the overall efficiency of the ESS. As a result, it was verified that the power plants’ electric powering capability can be curtailed. The amount of reduction is equal to that of 2nd Gori Nuclear Power Plant currently under construction. We calculated that approximately 320.85 L/day · MW of hydrogen is produced on a national scale. Also, Seoul’s demand output power of PEMFC and the requisite area of sites to install the PEMFC system are approximately 236 MW and 59059 m² respectively. This study can contribute to preventing the upsurge of the entire electric powering installed capability. Based on the present technology level, this study diagnoses the use of hydrogen-based ESS which will be introduced in the upcoming hydrogen economy period. Considering the water electrolysis by polymer electrolyte membrane water electrolyzers are currently at the beginning of commercialization and the energy density per mass of hydrogen is exceedingly high, we anticipate that the future of hydrogen base ESS’ effectiveness will reach greater levels than the analysis of this study.

Solid oxide fuel cells (SOFCs) are at a technological level close to commercialization, which could be enabled by new material research. Especially, not only an electrolyte, but also a cathode material becomes very important to further increase electrochemical performance, due to the effort to lower operating temperature of SOFCs to intermediate range (400-600℃) to take advantage of high and low temperature operation. Unfortunately, this trend inevitably results in demand for new cathode materials with high oxygen reduction reaction activity, as well as high mechanical durability. Recently, ceramic materials which conduct oxygen ion, proton, and electron, thereby called ‘triple conducting oxide’ are being highlighted, due to their excellent material properties, to be used for cathodes of SOFCs. This paper reviews the three representative triple-conducting oxides, which were already used and tested in SOFC operating conditions.

Thermoplastic fusion bonding is widely used to seal polymer microfluidic devices and optimal bonding protocol is required to obtain a successful bonding, strong bonding force without channel deformation. Besides, UV modification of the PMMA (poly-methyl methacrylate) is commonly used for chemical or biological application before the bonding process. However, study of thermal bonding for the UV modified PMMA was not reported yet. Unlike pristine PMMA, the optimal bonding parameters of the UV modified PMMA were 103˚C, 71 kPa, and 35 minutes. A very low aspect ratio micro channel (AR=1:100, 20 μm depth and 2000 μm width) was successfully bonded (over 95%, n>100). Moreover, thermal bonding of multi stack PMMA chips was successfully demonstrated in this study. The results may applicable to fabricate a complex 3 dimensional microchannel networks.