• KIEAE Journal
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• 제14권3호
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• pp.39-45
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• 2014

Energy poverty has been defined as low-income households who paid energy cost more than 10% of their ordinary income. Therefore, there are various subsidy programs focused on house remodeling for low-income households and one of them is the Home Energy Efficiency Assistance Program which have done by Korea Energy Foundation since 2007. The aim of the program is to improve the thermal performance of dilapidated dwellings and analyzed the detached house for the low-income households to develop the building typology. The database contained approximately 3,061 households which was obtained from the program in 2013 and the results of the study were like this; 1) For the shape of residential houses, the number of rectangular shaped building was higher than non-rectangular shaped ones. 2) For the orientation of buildings, the south layout of the detached housing was dominant to gain heating energy into buildings. 3) For the floor area, the average floor area was $44.2m^2$, although its size varied wide variations, which range from $6.3m^2$ to $107.1m^2$. 4) For the windows and doors, the south-facing window was larger than the other side. Finally it would be possible to determine the characteristics of residential houses for low-income families. A future study could establish typology of low-income housing that it would estimate the performance of each model building before and after the retrofit to improve the energy performance.

• 신재생에너지
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• 제5권2호
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• pp.15-24
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• 2009

As new small scale LFG (landfill gas) energy project model which can improve economic feasibility limited due to the economy of scale, LFG-Microturbine combined heat and power system with $CO_2$ fertilization into greenhouses was proposed and investigated including basic design process prior to the system installation at Gwang-ju metro sanitary landfill. The system features $CH_4$ enrichment for stable microturbine operation, reduction of compressor power consumption and low CO emission, and $CO_2$ supplement into greenhouse for enhancement plant growth. From many other researches, high $CO_2$ concentration was found to enhance $CO_2$ assimilation (also known as photosynthesis reaction) which converts $CO_2$ and $H_2O$ to sugar using light energy. For small scale landfills which produce LFG under $3\;m^3$/min, among currently available prime movers, microturbine is the most suitable power generation system and its low electric efficiency can be improved with heat recovery. Besides, since its exhaust gas contains very low level of harmful contaminants to plant growth such as NOx, CO and SOx, microturbine exhaust gas is a suitable and economically advantageous $CO_2$ source for $CO_2$ fertilization in greenhouse. The LFG-Microturbine combined heat and power generation system with $CO_2$ fertilization into greenhouse gas to enhance plant growth is technologically and economically feasible and improves economical feasibility compared to other small scale LFG energy project model.

• 한국멀티미디어학회논문지
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• 제23권2호
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• pp.293-300
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• 2020

Since the communication networks like the Internet collapses at disaster and calamity sites, a maintenance system that can be operated offline is required for the maintenance of various facilities. In this paper, we propose a system that memory tags attached on the facilities may transmit the emergency manual to a smart-phone, and the smart phone displays it off-line. The main issue is to design low energy mode memory tags. This study presents two kinds of methods and analyzes each's energy consumption mode. The first one is to develop memory tags by using one chip, and the next one is to design memory tags by forming multi-modules. Both ways show proper application fields under the low energy mode. This research selects the off-line maintenance system by using one chip design, and proposes the direction of contents for enhancing the effectiveness of the system. And we expect that this memory tags will be valuable for disaster scenes as well as battle fields.

• 한국수소및신에너지학회논문집
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• 제31권4호
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• pp.363-371
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• 2020

Recently, the technologies to utilize the cold energy of liquefied natural gas (LNG) have attracted significant attention. In this paper, thermodynamic performance analysis of combined cycles consisting of ammonia Rankine cycle (AWR) and organic Rankine cycle (ORC) with LNG Rankine cycle to recover low-grade heat source and the cold energy of LNG. The mathematical models are developed and the effects of the important system parameters such as turbine inlet pressure, ammonia mass fraction, working fluid on the system performance are systematically investigated. The results show that the thermal efficiency of AWR-LNG cycle is higher but the total power production of ORC-LNG cycle is higher.

• 전기학회논문지P
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• 제60권3호
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• pp.133-137
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• 2011

The purpose of smart grid is the low $CO_2$ through expansion of renewable energy. To achieve the purpose of smart grid, typical radial power distribution system will be changed to loop power distribution system. The loop power distribution system have many advantages such as low power loss, low voltage drop, and increase of connection of renewable energy. In this paper, the algorithm for minimization of interrupted section of power distribution system is proposed through communication between circuit breaker and recloser in loop power distribution system. The proposed algorithm is proved through case studies about reliability evaluation

• Nuclear Engineering and Technology
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• 제53권4호
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• pp.1259-1265
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• 2021

In the present study, a large-area hybrid gamma imaging system was designed by adopting coded aperture imaging on the basis of a large-area Compton camera to achieve high imaging performance throughout a broad energy range (100-2000 keV). The system consisting of a tungsten coded aperture mask and monolithic NaI(Tl) scintillation detectors was designed through a series of Geant4 Monte Carlo radiation transport simulations, in consideration of both imaging sensitivity and imaging resolution. Then, the performance of the system was predicted by Geant4 Monte Carlo simulations for point sources under various conditions. Our simulation results show that the system provides very high imaging sensitivity (i.e., low values for minimum detectable activity, MDA), thus allowing for imaging of low-activity sources at distances impossible with coded aperture imaging or Compton imaging alone. In addition, the imaging resolution of the system was found to be high (i.e., around 6°) over the broad energy range of 59.5-1330 keV.

• 한국컴퓨터정보학회논문지
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• 제24권3호
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• pp.29-39
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• 2019

In this study, we introduce a model that satisfies energy efficiency and economical efficiency by introducing and demonstrating cogeneration generators in industrial complexes using various actual data collected at the site. The proposed model is composed of three scenarios, ie, full - time operation, scenario operated according to demand, and a fusion type. In this study, the power generation profit and surplus thermal energy are measured according to the operation of the generator, and the thermal energy is traded according to the demand of the customer to calculate the profit and loss including the heat and evaluate the economic efficiency. As a result of the study, it is relatively profitable to reduce the generation of the generator under the condition that the electricity rate is low and the gas rate is high, while the basic charge is not increased. On the contrary, if the electricity rate is high and the gas rate is low, The more you start up, the more profit you can see. These results show that even a cogeneration power plant with a low economic efficiency due to a low "spark spread" has sufficient economic value if it can sell more than a certain amount of heat energy from a nearby customer and adjust the applied power through peak management.

• 에너지공학
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• 제24권3호
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• pp.48-54
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• 2015

중앙집중식 냉방 시스템을 적용하고 있는 대형 빌딩이나 플랜트 설비들의 경우 부하 증설 및 피크부하에 대응하기 위한 여유율을 반영한 설비 설계 및 시공이 이루어지고 있다. 이는 부분부하가 걸리는 기간 동안에는 설비의 저부하 운전으로 인한 장비의 효율 저하와 에너지 과소비의 원인이 된다. 본 연구는 부분부하에 효율적으로 대응할 수 있도록 냉방플랜트 최적 유량제어를 통한 에너지 절감 방안에 대한 연구로서 냉방플랜트 에너지 성능 분석 프로그램을 이용하여 냉방 부하를 분석하고, 최적 유량제어 시스템을 제안하여 그 에너지 성능을 비교 평가하는 것을 목적으로 한다. 성능 분석 결과 냉방플랜트 최적 유량제어 시스템 적용 시 기존 에너지 사용량 대비 약 17%의 전기에너지 절감이 가능하였다.

• 설비공학논문집
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• 제27권7호
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• pp.369-374
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• 2015

This study analyzed analyzes the energy performance of six houses in Daejeon completed which were built in 2011. Observed The observed houses, which were all designed and constructed inof the same size and structure, are were highly insulated with triple Low-E coating windows; the insulation level of the walls is was $0.13W/m^2K$ and that of the roof is was $0.10W/m^2K$. As electric houses, all of the energy supplied to the houses, including for cooking, is was supplied by electricity. A and 3~4 kWp of photovoltaic system and a 3~5 kW of ground source heat pump (GSHP) were installed in each house tofor providing provide space heating/and cooling and hot water are installed. We constructed a Web-based remote monitoring system in order to understand energy consumption and the dynamic behavior of the energy system. T, and the results of our metering data analysis of 2013 are as follows. First, the annual residential energy consumption is was 4,400 kWh (${\sigma}=1,209$) and GSHP energy consumption is was 5,182 kWh (${\sigma}=1,164$). Second, residential energy consumption ranked highest in average energy usage, with at 45% of the total, followed by heating with at 30%, hot water supply with at 17% and cooling with at 6%. Third, the average energy independence rate is was 51.8%, the GFA (Gross gross floor area) criteria average energy consumption unit is was $48.7kWh/m^2yr$ (${\sigma}=10.1$), and the net energy consumption unit (except the energy yield of the PV systems) is was $24.7kWh/m^2yr$ (${\sigma}=8.8$).

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 춘계 학술논문 발표대회
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• pp.198-199
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• 2015

Construction equipment is a major energy consumption source in construction projects. If 10% reduction of the diesel fuel usage is achieved in the construction industry, it may reduce 5% of the total energy usage. Energy saving operation is a major issue in equipment-intensive operations (e.g., earthmoving or paving operations). Identifying optimal equipment fleet is important measure to achieve low-energy consumption in those operations. This study presents a system which finds an optimal equipment fleet by computing the low-energy performance of earthmoving operations. It establishes construction operation model and compares numerous combinations using alternative equipment allocation plans. It implements sensitivity analysis that facilitates searching the lowest energy consumption equipment fleet by enumerating all cases.