• 한국수소및신에너지학회논문집
• /
• 제21권6호
• /
• pp.595-603
• /
• 2010

This paper deals with an economic evaluation of domestic window type photoelectrochemical hydrogen production utilizing solar cells. We make some sensitivity analysis of hydrogen production prices by changing the values of input factors such as the initial capital cost, the solar to hydrogen conversion efficiency, and the system duration time. The hydrogen production price of the window type photoelectrochemical system was estimated as 1,168,972 won/$kgH_2$. It is expected that hydrogen production cost can be reduced to 47,601 won/$kgH_2$ if the solar to hydrogen conversion efficiency is increased to 14%, the system duration time is increased to 20,000 hours, and the initial capital cost is decreased to 25% of the current level. We also evaluate the hydrogen production cost of the water electrolysis using the electricity produced by solar cells. The corresponding hydrogen production cost was estimated as 37,838 won/$kgH_2$. The photoelectrochemical hydrogen production is evaluated as uneconomical at this time, and we need to enhance the solar to hydrogen conversion efficiency and the system duration time as well as to reduce prices of the system facilities.

• 한국수소및신에너지학회논문집
• /
• 제21권1호
• /
• pp.64-71
• /
• 2010

This paper deals with an economic evaluation of domestic immersing type photoelectrochemical hydrogen production. We also make some sensitivity analysis of hydrogen production prices by changing the values of input factors such as the initial capital cost, the solar to hydrogen conversion efficiency, and the system duration time. The hydrogen production price of the immersing type photoelectrochemical system was estimated as 8,264,324 won/$kgH_2$. It is expected that the production cost by photoelectrochemical hydrogen production can be reduced to 26,961 won/$kgH_2$ if the solar to hydrogen conversion efficiency is increased to 14%, the system duration time is increased to 20,000 hours, and the initial capital cost is decreased to 10% of the current level. The photoelectrochemical hydrogen production is evaluated as uneconomical at this time, and we need to enhance the solar to hydrogen conversion efficiency and the system duration time as well as to reduce prices of the system facilities.

• 한국수소및신에너지학회논문집
• /
• 제24권4호
• /
• pp.282-287
• /
• 2013

Hydrogen production from water using solar energy is attractive way to obtain clean energy resource. Among the various solar-to-hydrogen production techniques, a combination of a photovoltaic and an electrolytic cell is one of the most promising techniques in term of stability and efficiency. In this study, we show successful fabrication of precursor solution processed CIGS thin film solar cells which can generate high voltage. In addition, CIGS thin film solar cell modules producing over 2V of open circuit voltage were fabricated by connecting three single cells in series, which are applicable to water electrolysis. The operating current and voltage during water electrolysis was measured to be 4.23mA and 1.59V, respectively, and solar to hydrogen efficiency was estimated to be 3.9%.

• 한국수소및신에너지학회논문집
• /
• 제19권4호
• /
• pp.322-330
• /
• 2008

This paper deals with an economic evaluation of domestic photobiological hydrogen production. We evaluate the economic feasibility of domestic photobiological hydrogen production utilizing green algae and cyanobacteria. In addition, we make some sensitivity analysis of hydrogen production prices by changing the values of input factors such as the price of a photo-bioreactor and the value of solar to hydrogen efficiency. The estimated hydrogen production price of the two-step indirect biophotolysis was 12,099won/kg$H_2$. It is expected that the hydrogen production price by the two-step indirect biophotolysis can be reduced to 2,143won/kg$H_2$ if the solar to hydrogen efficiency is increased to 10% and the price of a photo-bioreactor is decreased to $25/$m^2$. The two-step indirect biophotolysis is evaluated as uneconomical at this time, and we need to enhance the solar to hydrogen efficiency and to reduce the prices of the photo-bioreactor and system facilities.

• 한국수소및신에너지학회논문집
• /
• 제26권4호
• /
• pp.331-338
• /
• 2015

Solar air heaters (SAHs) are simple in design and widely used for solar energy collection devices, and a packed bed is one of typical solar energy storage systems of thermal energy captured by SAHs. This paper presents mathematical modeling and simulation on the thermal performance of various packed bed energy storage systems. A MATLAB program is used to estimate the thermal efficiency of packed bed SAH. Among the various packed bed energy storage systems considered, the wire mesh screen packed bed SAH shows the best thermal efficiency over the entire range of design conditions. The maximum of thermal efficiency of packed bed SAH with wire mesh screen matrices has been found to be 0.794 for Re=2000 - 20000 and ${\Delta}T/I=0.002-0.02$.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2009년도 하계학술대회 논문집
• /
• pp.438-438
• /
• 2009

We have investigated the effect of forming gas annealing for Upgraded Metallurgical Grade (UMG)-silicon solar cell in order to obtain low-cost high-efficiency cell using post deposition anneal at a relatively low temperature. We have observed that high concentration hydrogenation effectively passivated the defects and improved the minority carrier lifetime, series resistance and conversion efficiency. It can be attributed to significantly improved hydrogen-passivation in high concentration hydrogen process. This improvement can be explained by the enhanced passivation of silicon solar cell with antireflection layer due to hydrogen re-incorporation. The results of this experiment represent a promising guideline for improving the high-efficiency solar cells by introducing an easy and low cost process of post hydrogenation in optimized condition.

• 한국태양에너지학회 논문집
• /
• 제37권5호
• /
• pp.27-37
• /
• 2017

In this study, an artificial solar simulator composed of a 2.5 kW Xe-Arc lamp and mirror reflector was used to carry out the solar thermal two step thermochemical water decomposition cycle which can produce high efficiency continuous hydrogen production. Through various operating conditions, the change of hydrogen production due to the possibility of a dual-zone reactor and heat recovery were experimentally analyzed. Based on the reaction temperature of Thermal-Reduction step and Water-Decomposition step at $1,400^{\circ}C$ and $1,000^{\circ}C$ respectively, the hydrogen production decreased by 23.2% under the power off condition, and as a result of experiments using heat recovery technology, the hydrogen production increased by 33.8%. Therefore, when a thermochemical two-step water decomposition cycle is conducted using a dual-zone reactor with heat recovery, it is expected that the cycle can be operated twice over a certain period of time and the hydrogen production amount is increased by at least 53.5% compared to a single reactor.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2005년도 춘계학술대회
• /
• pp.102-108
• /
• 2005

We have developed highly stabilized (p-i-n)-type protocrystalline silicon (pc-Si:H) multilayer solar cells. To achieve a high conversion efficiency, we applied a double-layer p-type amorphous silicon-carbon alloy $(p-a-Si_{1-x}C_x:H)$ structure to the pc-Si:H multilayer solar cells. The less pronounced initial short wavelength quantum efficiency variation as a function of bias voltage proves that the double $(p-a-Si_{1-x}C_x:H)$ layer structure successfully reduces recombination at the p/i interface. It was found that a natural hydrogen treatment involving an etch of the defective undiluted p-a-SiC:H window layer before the hydrogen-diluted p-a-SiC:H buffer layer deposition and an improvement of the order in the window layer. Thus, we achieved a highly stabilized efficiency of $9.0\%$ without any back reflector.

• Applied Science and Convergence Technology
• /
• 제27권4호
• /
• pp.61-64
• /
• 2018

The basic principle and concept for hydrogen production via water-splitting process are introduced. In particular, recent research activities and their progress in the photoelectrochemical water-splitting process are investigated. The material perspectives of semiconducting photocatalysts are considered from metal oxides, including titanium oxides, to carbon compounds and perovskites. Various structural configurations, from conventional photoanodes with metal cathodes to tandem and nanostructures, are also studied. The pros and cons of each are described in terms of light absorption, charge separation/photoexcited electron-hole pair recombinations and further solar-to-hydrogen efficiency. In this research, we attempt to provide a broad view of up-to-date research and development as well as, possibly, future directions in the photoelectrochemical water-splitting field.

• 청정기술
• /
• 제19권3호
• /
• pp.191-200
• /
• 2013

미래의 무한 청정 에너지원으로 고려되고 있는 태양에너지를 활용하여 수소를 생산할 수 있는 광촉매재료에 대한 연구가 활발히 진행되고 있다. 본 총설에서는 태양광을 이용한 물분해 수소생산용 광촉매재료들에 대하여 알아보고, 현재까지 보고된 다양한 광촉매재료의 특성들을 검토하고자 한다. 또한, 다양한 광촉매재료를 활용하여 수소생산 효율을 높이기 위해서 시행되었던 촉매재료 개질 방법들을 통하여 향후 지속적으로 진행될 연구방향을 모색해 보고자 한다. 각각의 광촉매재료들이 활성을 가질 수 있는 빛의 영역을 알아보고, 광촉매 작용에 필수적인 광원, 광밀도, 파장영역 등의 중요성에 대해서도 토론한다.