• Transactions of the KSME C: Technology and Education
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• v.4 no.1
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• pp.35-41
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• 2016

Geothermal heat pump (GHP) systems have been proved to be one of the most efficient systems for heating and cooling in buildings. However, an optimal energy performance depends on a good control of the system components, including heat pumps and circulation pumps, which affect to the total energy consumption of system. This paper presents the simulation results of the heat pump performance for two different control schemes, i.e. constant setting temperature (Control-A) and variable setting temperatures (Control-B) in buffer tank. A dynamic simulation tool, TRNSYS 17, was used to model the entire system and to assess the performance of the system. Simulation results show that the Control-B, which controls the temperature in buffer tank with outdoor air temperature, is a effective way to reduce the energy consumptions in heat pump (7.7%) and circulation pump (7.5%).

• Journal of Biosystems Engineering
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• v.16 no.2
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• pp.167-177
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• 1991

곡물 빈에서 벼 건조시 외기 온도에 따른 연료 자동 조절 및 배출공기의 재순환이 에너지 소비, 건조비용 및 건조 시간에 미치는 효과를 분석하기 위해 슬램 II(SLAM II : Simulation Language for Alternative Modeing II)를 이용한 시뮬레이션 모텔을 개발하였다. 따라서 약 64톤의 벼를 연료 자동조절 버너를 갖춘 곡물빈에서 열풍 건조할 때, 절약 가능한 에너지 양과 공기 재순환의 효과를 시뮬레이션을 통해 분석하였으며 이를 실제의 자료와 비교하여 이 모델을 검증하였다. 시뮬레이션에 의한 본 연구의 결과는 다음과 같다. 1. 배출공기를 재순환 시키지 않는 상태에서 자동 연료조절 버너를 사용할 경우 관행 버너를 이용한 빈 시스템에 비해, 루이지애나 주에서 8월에 25%의 에너지를 절약할 수 있으며 12월에는 8%의 에너지를 절약할 수 있다. 실제의 건조 실험에서는 8월에 약 30%의 에너지를 절감할 수 있었다. 2. 자동 연료조절 버너를 갖춘 빈 시스템에서 제습을 하지 않은 배출 공기의 재순환은 건조 에너지 소비량과 건조 시간을 증가시켰으며 연료 자동조절 장치의 에너지 절약 효과를 감소시켰다. 따라서 배출 공기를 재순환하여 에너지를 절감하고자 할 때에는 반드시 배출 공기를 제습시켜 습도를 재조절 해야만 했다. 또한 제습된 공기의 재순환 효과는 여름보다 겨울에 더 컸다. 3. 연료 자동조절 버너를 갖춘 빈 시스템에서 벼를 건조할 경우 루이지애나 주, 8월에 물벼의 톤당 건조 비용은 $2.13이었으며 관행 버너를 갖춘 시스템에서는 $2.69이었다. 실험에 의한 실제 건조비용은 자동화 시스템에서 $2.17이었고 관행 시스템에서는 $2.62이었다.

• Environmental and Resource Economics Review
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• v.23 no.2
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• pp.305-330
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• 2014

There has been a lot of studies to identify the driving forces of energy consumption. Many of them decomposed the final energy consumption into the intensity effect, structural effect, and production effect. Those approach, however, could not consider the transformation loss during the electric power generation. Therefore, in this study, we conducted a decomposition analysis on the primary energy use basis to reflect that transformation loss. Log mean Divisia index and refined Laspeyres methods were used for the index decomposition. As results, we could find out that the difference between two approaches were definite. The intensity effect in 2011 is -0.607 times against 1981 in the final energy case, but -0.236 times in the primary energy case. The structure effect in 2011 is 0.227 times against 1981 in the final energy case, but 0.434 times in the primary energy case. Therefore, an analysis on the primary energy basis is essential when conducting a decomposition analysis.

• Environmental and Resource Economics Review
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• v.21 no.3
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• pp.543-572
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• 2012

This paper compared historical energy use from 2000 between Japan and Korea and reviewed literature of mid-and long-term low carbon energy scenarios and plans in both countries released since 2000. In terms of energy use pattern, there are similarities between Korea and Japan; high dependence on energy imports, high proportion of manufacturing industry among OECD countries, closed electricity system disconnected with foreign countries, and high proportion of nuclear power generation with low proportion of renewable electricity despite of high potential of renewable energy. Differences are as follows; decreasing trend in Japan and increasing trend in Korea in terms of energy demand and supply, difficulty of exchanging electricity between regions in Japan unlike Korea, and prospect of nuclear power, that is, curtailing in Japan while expanding in Korea according to governmental plan. Energy Basic Plan in both countries established before nuclear accident in Fukushima required expanding about two times of nuclear energy by 2030, while civil society's energy scenarios suggested reducing energy demand, phasing-out nuclear power, and expanding renewable energy. This paper will serve as a base for future studies about long-term energy scenarios and plan in Japan and Korea.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.4
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• pp.399-404
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• 2015

The cost of fuel in ships has recently increased due to a rapid increase in international oil prices and international restrictions regarding the greenhouse effect generated from the burning of fuel. Therefore, different methods for changing the hull designs for improving energy efficiency, developing coating for reducing friction resistances, developing additives for improving engine thermal efficiency, and low-speed operation for reducing fuel consumption have been considered. The developments of high-speed, large-scale, and energy-saving vessels are deemed essential to adapt to the recent high oil price era. Therefore, it is important to analyze Precisely the qualitative and quantitative changes in the resistance value of the local areas of the hull surface. In this study, the engine performance before and after docking was analyzed to examine friction resistance caused by marine growth on the hull as a basic study for improving the energy efficiency. The result was then presented by comparing it with the previous data for 2.5 years between docks to investigate the performance of the main engine, the change in friction resistances and loads, the fuel consumption and ship speed.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.256-263
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• 2011

Recently, curtain wall structure is constructed according to increasing high rise building. Glass is usually used in opening of curtain wall structure and window area ratio is finally increased. Excessive Daylighting and solar radiation by large window area ratio cause discomfort glare and add to cooling load in the case of office that is heavy on lighting and cooling. Therefore, this study suggests to use low transmittance window for solve those problems. Indoor lighting environment and building energy performance were analyzed by increasing transmittance from 10% to 90% and comparing fixed venetian blind. Consequently, the range of transmittance that is possible to daylighting and prevent discomfort glare. Secondary energy consumption is efficient in the case that transmittance is the range of from 20% to 50%, primary energy consumption is nice on from 20% to 40%. If those result put together, the range of window transmittance from 30% to 50% is proper in the office in lighting environment and energy consumption aspects.

• Environmental and Resource Economics Review
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• v.4 no.1
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• pp.91-102
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• 1994

우리나라에서 다른 광물자원보다 매장량이 비교적 풍부하고 에너지원으로서 총에너지소비량에서 중요한 몫을 차지해 온 석탄의 희소성을 측정하기 위하여 시장가격을 사용할 경우 그 결과는 실질고갈상태를 왜곡시킬 수 있다. 왜냐하면 정부가 석탄가격을 관리하며 생산원가보다 낮은 부분에 대해서는 보조금이나 장려금을 지급해 왔기 때문이다. 그러므로 본 연구는 쌍대성이론(duality theory)을 토대로 한 할버슨-스미스(Halvorsen-Smith, 1984) 모형을 이용하여 매장되어 있는 광물자원의 암묵가격(shadow price)을 실증적으로 추정함으로써 우리나라 석탄자원의 희소성을 측정하였다. 최종생산물의 가격으로 측정된 희소성지표에 의하면 우리나라의 석탄자원은 매우 완만하게 고갈되어 가고 있는 반면에 광석의 암묵가격으로 본 회소성지표에 의하면 그보다 더 빠른 속도로 고갈되어 가고 있음을 알 수 있었다.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.121-128
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• 2005

This is about experimental comparison study between convective heating and radiation heating system to use the design criteria for residential house. Experiment was done in EC(environment chamber) under simultaneous outdoor condition for 4 kinds of heating system such as CRHP(Ceiling Radiant Heating Panel), BEHC( Bottom Electric Heating Coil Mat), EFCU( Electric Fan Coil Unit) and CEHU( Convective Electric Heating Unit). Result show that CRHP ,which is radiation heating system, can consume more 23% energy than convective heating system when it is operated by dry bulb temperature but can save 1 ${\sim}$ 10% when operated by glove temperature and 27% when operated by MRT.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.193-195
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• 2011

Nowadays, climatic environment change has become a major issue in the world. This causes major emissions of carbon dioxide industries steel industry, thermal power industry, cement industry is essential in the reduction of carbon dioxide, which is based on total carbon dioxide emissions account for most of the construction industry in an effort to minimize the environmental load is needed. accordingly, through case studies, It can be induce the selection to minimize environmental load by comparing the output of quantitative energy consumption and carbon dioxide emissions per constructional methods. As a result of this study, RC Structure was less environmental load than SC structure.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.333-336
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• 2008

There are many different kinds of forming processes to make a tubular product such as hydroforming and tube drawing. However, we should consider a better forming process in view point of energy consumption and $CO_2$ emission to save our earth. In this paper we have conducted FEM simulations to the various forming processes for sheet and tubular products to compare their energy consumptions. One example is tubular product and the other for drawn cup. From the comparisons of total energy for hydrofroming and tube sinking processes, hydroforming is consumed more energy than tube drawing. Also the cup drawing from sheet metal and tube sinking for the cup with flange indicate that the tube sinking is better than cup drawing of sheet metal in energy consumption.