• 제목/요약/키워드: Natural energy

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Natural Gas Combustion Characteristics of Mass Produced Oxygen Carrier Particles for Chemical-looping Combustor in a Batch Type Fluidized Bed Reactor (회분식 유동층 반응기에서 매체순환식 가스연소기용 대량생산 산소공여입자들의 천연가스 연소특성)

  • Ryu, Ho-Jung;Kim, Kyung-Su;Park, Yeong-Seong;Park, Moon-Hee
    • Journal of Hydrogen and New Energy
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    • v.20 no.2
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    • pp.151-160
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    • 2009
  • Natural gas combustion characteristics of mass produced oxygen carrier particles were investigated in a batch type bubbling fluidized bed reactor. Five particles, NiO/bentonite, OCN601-650, OCN702-1100, OCN703-950, OCN703-1100 were used as oxygen carrier particles. Natural gas and air were used as reactants for reduction and oxidation, respectively. During reduction reaction, high fuel conversion and high $CO_2$ selectivity were achieved for most of oxygen carriers. During oxidation, NO emission was very low. These results indicate that inherent $CO_2$ separation and low NOx combustion are feasible for the natural gas fueled chemical-looping combustion system. Among the five oxygen carriers, OCN703-1100 particle was selected as the best candidate for demonstration of long-term operation in large-scale chemical-looping combustor from the viewpoints of fuel conversion, $CO_2$ selectivity, $CH_4$ concentration, and CO concentration.

An Estimation of Quantity of Unused Energy of River Water, Seawater and Treated Sewage as Heat Source and Its Availability in Large Facilities (대규모 시설에서 이용가능한 미활용 에너지의 부존량과 그 이용 가능성에 관한 조사연구-하천수.해수.하수처리수를 중심으로)

  • Heo, Jae-Yeong
    • Journal of National Security and Military Science
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    • s.1
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    • pp.423-446
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    • 2003
  • While the demand for energy has shown a sharp increase recently, the supply seems to be limited by the fact that the conventional fossil fuel energy or nuclear energy has its own environmental problems such as, for example, global warming or nuclear waste disposal. To overcome such limited supply of energy, the utilization of natural thermal energy such as river water and seawater as well as treated sewage can be a substantial supplement. The potential use of the unused energy has become more and more feasible these days as the heat pump technology has been advanced. In the present study, the unused energy resources are estimated on regional and monthly basis for each resource by the method proposed here in order to establish the fundamental data for its utilization. The potential use of the unused energy is a1so discussed.

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Analysis on the EU Energy Market Trends and Policies

  • Kim Eun-Sun;Koo Young-Duk;Park Young-Seo
    • Journal of information and communication convergence engineering
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    • v.3 no.2
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    • pp.63-66
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    • 2005
  • In 2000, the EU set up an energy policy related renewables use for electricity demand up to $22\%$ on the purpose of preventing energy exhaustion and world climate exchange. Technology development and energy production policy on coal, oil and natural gas focus on how to minimize their environmental effects since the world energy system will continue to be dominated by fossil fuels with almost $90\%$ of total energy supply in 2030. In the long run, the EU drives expansion policy of the renewable energy. If related policies and programs will show successful operation in the near future and will be resulted in increase of budget, we could expect the possibility of expansion of renewable energy market in Korea in the future.

Exhaust Emissions Characteristics of Bi-fuel CNG/LPG Passenger Cars (CNG/LPG Bi-fuel 승용차의 배출가스 특성)

  • Cho, Chong-Pyo;Lee, Young-Jae;Kim, Gang-Chul;Kwon, Oh-Seuk
    • Transactions of the Korean Society of Automotive Engineers
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    • v.19 no.2
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    • pp.142-147
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    • 2011
  • Compressed natural gas (CNG) is well known as one of the cleanest burning alternative fuels. Bi-fuel CNG vehicle can also run on gasoline or another fuel while dedicated natural gas vehicle is designed to run on natural gas only. Recently, increased attention has been focused on bi-fuel CNG/LPG taxi because of good fuel economy of CNG. A number of LPG taxis modified to CNG Bi-fuel vehicles are running in many cities. In this paper, the emissions characteristics of in-use passenger cars running on CNG and LPG were investigated. Chassis dynamometer test was used to measure exhaust emissions from an in-use fleet of 5 cars. Exhaust emissions were collected for CVS-75 driving mode. The test results showed that for CNG fuel mode, CO, $CO_2$ and NMHC emissions decreased to 9%, 12% and 14% respectively, and $CH_4$ and $NO_x$ emissions increased to 317% and 47% respectively.

Sustainable Tall Buildings: Summary of Energy-Efficient Design

  • Kheir Al-Kodmany;Mir M. Ali;Paul J. Armstrong
    • International Journal of High-Rise Buildings
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    • v.12 no.2
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    • pp.107-120
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    • 2023
  • Tall buildings are frequently decried as unsustainable due to their excessive energy usage. Early skyscrapers used natural light and ventilation to facilitate human comfort and applied organic materials such as stone, glass, wood, concrete, and terra cotta for cladding and finishes. With the advent of fluorescent lighting, modern heating, ventilation, air-conditioning (HVAC) systems, and thermally sealed curtain walls, tall office buildings no longer had to rely on natural light and ventilation to provide comfort. Energy efficiency was not a significant factor when the operational costs of buildings were relatively inexpensive. However, today's skyscrapers must become more energy-efficient and sustainable due to energy crises and climate change. This paper highlights vital energy-efficient design principles and demonstrates with illustrative case studies how they are applied to tall buildings in various parts of the world. It shows how sustainable environmental systems do not act alone but are integrated with advanced curtain wall systems, sky gardens, and atria, among others, to regulate and sustain thermal comfort and conserve energy.

Study on the Improvement of Efficiency in Dehydration Process of LNG Liquefaction Plant Using Molecular Sieve (분자체를 이용한 LNG 액화 플랜트 탈수 공정의 효율성 향상에 관한 연구)

  • JONGHWA PARK;DONSANG YU;DAEMYEONG CHO
    • Journal of Hydrogen and New Energy
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    • v.35 no.1
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    • pp.105-113
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    • 2024
  • The natural gas dehydration process plays a central role in liquefying LNG. This study proposes two natural gas dehydration process systems applicable to liquefied natural gas (LNG) liquefaction plants, and compares and analyzes energy optimization measures through simulation. The fuel gas from feed stream (FFF) case, which requires additional equipment for gas circulation, disadvantages are design capacity and increased energy. On the other hand, the end flash gas (EFG) case has advantages such as low initial investment costs and no need for compressors, but has downsides such as increased power energy and the use of gas with different components. According to the process simulation results, the required energy is 33.22 MW for the FFF case and 32.86 MW for the EFG case, confirming 1.1% energy savings per unit time in the EFG case. Therefore, in terms of design pressure, capacity, device configuration, and required energy, the EFG case is relatively advantageous. However, further research is needed on the impact of changes in the composition of regenerated gas on the liquefaction process and the fuel gas system.

The Acoustic Emission Energy Analysis of Subambient Pressure Tri-Pad Slider

  • Pan Galina;Hwang Pyung;Xuan Wu
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2004.11a
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    • pp.139-142
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    • 2004
  • The object of the present work is the acoustic emission energy analysis of subambient pressure tri-pad slider. Head/disk interaction during start/stop and constant speed were detected by using acoustic emission (AE) test system The frequency spectrum analysis is performed using the AE signal obtained during the head/disk interaction Natural frequency analysis was performed using Ansys program. Acoustic emission energy was calculated for the slider modes.

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Theoretical Studies on Dicyanoanthracenes as Organic Semiconductor Materials: Reorganization Energy

  • Park, Young-Hee;Kim, Yun-Hi;Kwon, Soon-Ki;Koo, In-Sun;Yang, Ki-Yull
    • Bulletin of the Korean Chemical Society
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    • v.31 no.6
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    • pp.1649-1656
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    • 2010
  • Internal reorganization energy due to the structural relaxation in hole or electron hopping mechanism is one of the measurements of key indices in designing an organic thin film transistor (OTFT) for flexible display devices. In this study, the reorganization energies of dicyanoanthracenes for the hole and electron transfer were estimated by adiabatic potential energy surface and normal mode analysis method in order to examine the effect on the energies for the positional variation of the cyano substituents in the anthracene as a protocol of acenes to design an organic field effect transistor. The reorganization energy for the hole transfer was reduced considerably upon cyanation of anthracene, especially at the 9,10-positions of anthracene, and the origin of the reduction was interpreted in terms of understanding the coupling of vibrational modes to the hole transfer.

An Experimental Study on the Natural Convection Heat Transfer of Air-cooling PEMFC in a Enclosure (밀폐된 공간 내 공랭식 PEMFC의 자연대류 열전달에 대한 실험적 연구)

  • LEE, JUNSIK;KIM, SEUNGGON;SOHN, YOUNGJUN
    • Journal of Hydrogen and New Energy
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    • v.27 no.1
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    • pp.42-48
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    • 2016
  • This study presents an experiment investigation on natural convection heat transfer of air-cooling Proton exchange membrane fuel cells (PEMFCs) in a enclosure system for unmanned aerial vehicles (UAVs). Considered are replacing fuel cell stack with Aluminum block for heat generating inside a enclosure chamber. The volume ratio of fuel cell stack and chamber for simulation to the actual size of aerial vehicle is 1 to 15. The parameters considered for experimental study are the environmental temperature range from $25^{\circ}C$ to $-60^{\circ}C$ and the block heat input of 10 W, 20 W and 30 W. Effect of the thermal conductivity of the block and power level on heat transfer in the chamber are investigated. Experimental results illustrate the temperature rise at various locations inside the chamber as dependent upon heat input of fuel cell stack and environmental temperature. From the results, dimensionless correlation in natural convection was proposed with Nusselt number and Rayleigh number for designing air-cooling PEMFC powered high altitude long endurance (HALE) UAV.

A Current Status of Natural Analogues Programs in Nations Considering High-Level Radioactive Waste Disposal

  • HunSuk Im;Dawoon Jeong;Min-Hoon Baik;Ji-Hun Ryu
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.21 no.1
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    • pp.65-93
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    • 2023
  • Several countries have been operating radioactive waste disposal (RWD) programs to construct their own repositories and have used natural analogues (NA) studies directly or indirectly to ensure the reliability of the long-term safety of deep geological disposal (DGD) systems. A DGD system in Korea has been under development, and for this purpose a generic NA study is necessary. The Korea Atomic Energy Research Institute has just launched the first national NA R&D program in Korea to identify the role of NA studies and to support the safety case in the RWD program. In this article, we review some cases of NA studies carried out in advanced countries considering crystalline rocks as candidate host rocks for high-level radioactive waste disposal. We examine the differences among these case studies and their roles in reflecting each country's disposal repository design. The legal basis and roadmap for NA studies in each country are also described. However because the results of this analysis depend upon different environmental conditions, they can be only used as important data for establishing various research strategies to strengthen the NA study environment for domestic disposal system research in Korea.