수소는 다양한 신재생에너지 중 환경친화적인 에너지로 각광받고 있지만 농업에 적용된 사례는 드물다. 본 연구는 수소 연료전지 삼중 열병합 시스템을 온실에 적용하여 에너지를 절 약하고 온실가스를 줄이고자 한다. 이 시스템은 배출된 열을 회수하면서 수소로부터 난방, 냉각 및 전기를 생산할 수 있다. 수소 연료 전지 삼중 열 병합 시스템을 온실에 적용하기 위해 서는 온실의 냉난방 부하 분석이 필요하다. 이를 위해서는 온 실의 형태, 냉난방 시스템, 작물 등을 고려해야 한다. 따라서 본 연구에서는 건물 에너지 시뮬레이션(BES)을 활용하여 냉 난방 부하를 추정하고자 한다. 전주지역의 토마토를 재배하 는 반밀폐형 온실을 대상으로 2012년부터 2021년까지의 기 상데이터를 수집하여 분석했다. 온실 설계도를 참고하여 피 복재와 골조를 모델화하여 작물 에너지와 토양 에너지 교환을 실시했다. 건물 에너지 시뮬레이션의 유효성을 검증하기 위 해 작물의 유무에 의한 분석, 정적 에너지 및 동적 에너지 분석 을 실시했다. 또한 월별 최대 냉난방 부하 분석에 의해 평균 최 대 난방 용량 449,578kJ·h-1, 냉방 용량 431,187kJ·h-1이 산정 되었다.

본 연구에서는 선박 전원용 연료전지 시스템 모델을 개발하여 순수한 산소를 공급하여 진행한 실험 결과의 비교를 통하여 연료전지 시스템 모델을 검증하였다. 검증된 모델을 활용하여 공기 압축기를 사용하여 공기를 공급할 경우에 대하여 산소를 공급한 경우와의 연료전지 출력 특성을 비교 검토하였다. 또한, 연료전지 시스템의 열물성치 변화가 스택의 출력에 어떠한 영향을 미치는지에 관하여 검토하였다. 그 결과 본 연구의 실험 범위에서 캐소드 공급 가스로 순수한 산소를 공급한 경우의 모델링을 통한 계산 결과와 실험 결과는 전 부하 영역에서 거의 동일한 전압 및 출력을 얻을 수 있었다. 560 A의 일정한 부하에서 캐소드 공급용 산소를 대신하여 공기를 공급한 경우 각각의 스택 전압은 약 14 V, 스택 출력은 약 8 kW, 스택 효율은 약 3 % 및 전체 시스템 효율은 8 % 정도 낮아짐을 알 수 있었다. 본 연구에서 검토한 열물성치 중에서 스택에 대한 냉각수의 열전달 계수가 스택의 출력에 가장 큰 영향을 미침을 알 수 있었다.

Polymer electrolyte membrane (PEM) is one of key elements to determine both electrochemical performances and lifetimes of fuel cell electric vehicles (FCEVs). PEM is exposed to a variety of dynamic stimuli (e.g., temperature, humidity, pressure, fuel gases and so on) under their operation conditions and meets unavoidable mechanical damages derived from unequal pressure difference between anode and cathode feed gases. Even though there have been approaches to evaluate the mechanical strength of PEM materials, most of the trials could provide static information on their mechanical strength. In this study, a pressure-loaded blister hybrid system connected with gas chromatography was developed to disclose the efficacy of the system as an evaluation tool of dynamic PEM strength under realistic FCEV operation conditions.

La1-xSrxMnO3(LSM,0≤x≤0.5) powders as the air electrode for solid oxide fuel cell were synthesized by a glycine-nitrate combustion process. The powders were then examined by X-ray diffraction(XRD) and scanning electron microscopy (SEM). The as-formed powders were composed of very fine ash particles linked together in chains. X-ray maps of the LSM powders milled for 1.5 h showed that the metallic elements are homogeneously distributed inside each grain and in the different grains. The powder XRD patterns of the LSM with x< 0.3 showed a rhombohedral phase; the phase changes to the cubic phase at higher compositions(x≥0.3) calcined in air at 1200˚C for 4 h. Also, the SEM micrographs showed that the average grain size decreases as Sr content increases. Composite air electrodes made of 50/50 vol% of the resulting LSM powders and yttria stabilized zirconia(YSZ) powders were prepared by colloidal deposition technique. The electrodes were studied by ac impedance spectroscopy in order to improve the performance of a solid oxide fuel cell(SOFC). Reproducible impedance spectra were confirmed using the improved cell, which consisted of LSM-YSZ/YSZ. The composite electrode of LSM and YSZ was found to yield a lower cathodic resistivity than that of the non-composite one. Also, the addition of YSZ to the La1-xSrxMnO3 (0.1≤x≤0.2) electrode led to a pronounced, large decrease in the cathodic resistivity of the LSM-YSZ composite electrodes.

Joining of NiO-YSZ to 316 stainless steel was carried out with B-Ni2 brazing alloy (3 wt% Fe, 4.5 wt% Si, 3.2 wt% B, 7 wt% Cr, Ni-balance, m.p. 971-) to seal the NiO-YSZ anode/316 stainless steel interconnect structure in a SOFC. In the present research, interfacial (chemical) reactions during brazing at the NiO-YSZ/316 stainless steel interconnect were enhanced by the two processing methods, a) addition of an electroless nickel plate to NiO-YSZ as a coating or b) deposition of titanium layer onto NiO-YSZ by magnetron plasma sputtering method, with process variables and procedures optimized during the pre-processing. Brazing was performed in a cold-wall vacuum furnace at . Post-brazing interfacial morphologies between NiO-YSZ and 316 stainless steel were examined by SEM and EDS methods. The results indicate that B-Ni2 brazing filler alloy was fused fully during brazing and continuous interfacial layer formation depended on the method of pre-coating NiO-YSZ. The inter-diffusion of elements was promoted by titanium-deposition: the diffusion reaction thickness of the interfacial area was reduced to less than 5 compared to 100 for electroless nickel-deposited NiO-YSZ cermet.

Ground source heat pumps are clean, energy-efficient and environment-friendly systems. Although the initial cost of ground source heat pump system is higher than that of air source heat pump, it is now widely accepted as an economical system since the installation cost can be returned within an short period of time due to its high efficiency. In the present study, performances of ground source compound hybrid heat pump system applied to a resort building are simulated. The system design and operation process appropriate for the surrounding circumstance guarantee the high benefit of the heat pump system applied to a resort building. If among several renewable energy sources, ground, river, sea, waste water source are chosen as available alternative energies are combined, COP of the system can be increased largely and hybrid heat pump system can reduced the fuel cost.

In developing new generation vehicles, the fuel cell hybrid vehicle has become more important as environmental standards become more stringent. This paper details the Fuel Cell Hybrid Radio Control Car (FCHRC) with proton exchange membrane fuel cell stack(75×55×65mm, 6V, 5A) and a secondary battery(7.4V, 2A) charged up by a solar cell(61mm x 110mm, 1.7V, 450mA). The design work of the FCHRC was made progress by CATIA modeling & assembling before manufacturing it. In this paper, we will focus on the automatic conversion of a power source between the PEMFC and the secondary battery, and finding the optimum conditions (temperature, humidity, airflow rate and hydrogen pressure) through thousands of performance tests in the humidity-temperature program controller. The purpose is that the models and data from the experiments we conducted will contribute to the ongoing development of the fuel cell hybrid car.

Livestock wastewater has high potential as one of energy resources because this wastewater is including high organic matter. Therefore the studies attempting to bio-gasification and bio-electricity generation using livestock wastewater is being tried. The pre-treatment system used in this study was the purpose to control the ammonia nitrogen in conjunction with the system and the microbial fuel cell. Because ammonia nitrogen is to inhibit the electricity generation efficiency of microbial fuel cell. These studies were to ascertain the effect of oxidants on the nitrogen removal in the pre-treatment system using catalyst and microbubbles to treat the ammonia nitrogen. The three kinds of oxidant such as air, oxygen (O2), and hydrogen peroxide (H2O2) were used to know the ammonia and nitrate nitrogen removal. This system was operated with four kinds of conditions. First method is O2 gas with 100 mL/min with 1ml of 30% H2O2 was supplied to the wastewater. A second method, the O2, with 400 and 1,000 mL/min was supplied through the flow meter before livestock wastewater was flow in the reactor. The last method, air was supplied 800 mL/min. The nitrate removal had no significant difference all conditions except the air supply. On the other hand, the ammonia and nitrate nitrogen removal when oxygen was supplied with 1000 mL O2/min was higher than that of the other conditions. The removal rate when air was supplied 800 mL/min was similar to the value in the supplied with 400 ml O2/min. This result showed that oxidant was important factor to improve the ammonia nitrogen removal rate.

해양구조물 전력시스템은 독립형 전력체계를 구축하기 어렵다. 그러므로 해상용 전력시스템을 효과적으로 운영하기 위하여 연료전지 및 하이브리드 전력체계를 연동한 전력시스템을 구축하는 것이 중요하다. 본 연구에서는 연료전지 기반의 해양구조물용 전력체계 설계에 필요한 수소 발생 메카니즘, 사용 전력량 계산과정 등을 기초로 해상용 연료전지 기반의 전력체계를 설계하고, 설계된 전력 시스템을 LabVIEW 프로그램을 활용하여 시뮬레이션 및 분석하였으며, 이를 기반으로 해양구조물용 전력시스템 설계 방안을 제안하고자 한다.

Sediment works as a resource for electric cells. This paper was designed in order to verify how sediment cells work with anodic material such as metal and carbon fiber. As known quite well, sediment under sea, rivers or streams provides a furbished environment for generating electrons via some electron transfer mechanism within specific microbial population or corrosive oxidation on the metal surfaces in the presence of oxygen or water molecules. We experimented with one type of sediment cell using different anodic material so as to attain prolonged, maximum electric power. Iron, Zinc, aluminum, copper, zinc/copper, and graphite felt were tested for anodes. Also, combined type of anodes-metal embedded in the graphite fiber matrix-was experimented for better performances. The results show that the combined type of anodes exhibited sustainable electricity production for ca. 600 h with max. 0.57 W/㎡ Al/Graphite. Meanwhile, graphite-only electrodes produced max. 0.11 W/㎡ along with quite stationary electric output, and for a zinc electrode, in which the electricity generated was not stable with time, therefore resulting in relatively sharp drop in that after 100 h or so, the maximum power density was 0.64 W/㎡. It was observed that the corrosive reaction rates in the metal electrodes might be varied, so that strength and stability in the electric performances(voltage and current density) could be affected by them. In addition to that, COD(chemical oxygen demand) of the sediment of the cell system was reduced by 17.5∼36.7% in 600 h, which implied that the organic matter in the sediment would be partially converted into non-COD substances, that is, would suggest a way for decontamination of the aged, anaerobic sediment as well. The pH reduction for all electrodes could be a sign of organic acid production due to complicated chemical changes in the sediment.