• 한국수산과학회지
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• 제46권6호
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• pp.807-812
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• 2013

The energy budget of the larvae of pandalid shrimp, Pandalopsis japonica, reared in the laboratory from zoea to post-larva was investigated. Energy used during the growth of the shrimp larvae was calculated daily for feeding, growth, molting, and metabolism. The total energy used was 16.2 J for the entire larval stage. Molting energy loss was estimated at a total 1.03 J. Energy used for respiration was estimated at a total of 1.85 J. The intake energy by feeding reached a total of 77.69 J. The total sum of energies used by excretion and egestion was 58.61 J. Larvae assimilated 24.57% of ingested food and used 84.91% for somatic growth. The gross growth efficiency ($K_1$) was 22.19% for the entire larval stage, and the net growth efficiency ($K_2$) was 90.31%. Maintenance costs were estimated at 9.69% of assimilated energy for the entire larval stage.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.321-324
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• 2009

The unpredicted worldwide oil price makes the energy efficiency technology be more importance than any other period. The small cogeneration system is one of the most representative technology among the energy efficiency technologies, and recently, the household cogeneration system has been the center object of attention because of the loss of power transmission and the reasonable energy consumption relative to the household (condensing) boiler producing heat only. A tiny, 1kW of electrical output, gas fueled internal combustion engine cogeneration system was investigated. The electrical efficiency and thermal efficiency of the system were measured. With the emission characteristics, the cogeneration system was analyzed. It was showed the gas engine cogeneration system produced the lowest NOx level compared any other cogeneration system due to the three-way catalyst.

• 한국태양에너지학회 논문집
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• 제26권1호
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• pp.7-12
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• 2006

The dish type solar thermal concentrating system can collect the solar energy above $800^{\circ}C$. It has a concentration ratio of 800 and total reflector area of $49m^2$. To operate solar receivers at high temperature, the optimum aperture size is obtained from a comparison between maximizing absorbed energy and minimizing thermal losses. The system efficiency is defined as the absorbed energy by working fluid in receiver divided by the energy coming from the concentrator. We find that system efficiency is stable in case of flow rate of above 6lpm. The system efficiency are 64.9% and 65.7% in flow rate of 6lpm and 8lpm, respectively. The thermal performance showed that the maximum efficiency and the factor of thermal loss in flow rate of 8lpm are 68% and 0.0508.

• 한국초전도ㆍ저온공학회논문지
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• 제22권4호
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• pp.45-50
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• 2020

In this research, the variation of round-trip efficiency in a liquid air energy storage system (LAES) is calculated and an optimal configuration is found. The multiple stages of cold energy storage are simulated with several materials that process latent heat at different temperature ranges. The effectiveness in the charging and discharging processes of LAES is newly defined, and its relationship with the round-trip efficiency is examined. According to defined correlation, the effectiveness of the discharging process significantly affects the overall system performance. The round-trip efficiency is calculated for the combined cold energy storage materials of aqueous dimethyl sulfoxide (DMSO) solution, ethanol, and pentane theoretically. The performance of LAES varies depending on the freezing point of the cold storage materials. In particular, when the LAES uses several cold storage materials, those materials whose freezing points are close to room temperature and liquid air temperature should be included in the cold storage materials. In this paper, it is assumed that only latent heat is used for cold energy storage, but for more realistic analyzes, the additional consideration of the transient thermal situation to utilize sensible heat is required. In the case of such a dynamic system, since there is certainly more increased heat capacity of the entire storage system, the volume of the cold energy storage system will be greatly reduced.

• 통상정보연구
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• 제16권2호
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• pp.199-218
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• 2014

본 연구는 1995년부터 2010년까지 국가 에너지통계의 에너지소비, 생산, 수출 입 등 실적자료를 바탕으로 우리나라의 에너지경제효율을 분석하였다. 에너지 수출 입과 에너지 생산 자료를 통해 에너지원단위, 에너지순수입의존도, 에너지자립도 I, II 를 산출하고 국가경제규모와 비교분석을 통해 우리날 에너지경제 수준을 살펴보고 시사점을 제시하는데 목적이 있다. 에너지원단위 지표를 통한 에너지효율수준 분석이 주로 이루어졌다면, 본 연구는 에너지순수입의존도와 에너지자립도를 통해 국가 에너지 수출 입구조와 에너지생산수준을 추가적으로 살펴볼 수 있는 장점이 있다고 하겠다. 연구 결론으로 우리나라는 에너지경제효율 수준이 상당히 낮은 수준으로 국가적 정책 차원의 에너지효율개선의 필요성을 제기한다.

• 설비공학논문집
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• 제26권1호
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• pp.1-7
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• 2014

A field test of a 70 kW heat pump system with flue gas heat recovery was performed by an experiment at the Korea Institute of Energy Research. The flue gas is exhausted from a 320 RT absorption chiller-heater in the heating season. Using this flue gas, source water of the heat pump is heated by a condensed-type heat exchanger in the chimney. The operating characteristics of the heat recovery heat pump system were analyzed. Based on the results of the experiments, operating maps were obtained, and an optimum operating range is suggested, in which the return and heat source water temperature are $51^{\circ}C$ and $31^{\circ}C$, respectively. Additionally, economic analysis of this system was conducted and about 50% energy cost savings can be expected in the heating season.

• 조명전기설비학회논문지
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• 제21권7호
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• pp.117-123
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• 2007

제조업에서 생산설비에 사용되는 중요한 에너지원 중 하나는 전력에너지이며, 에너지 다소비 업종의 생산설비 즉, 플랜트에서는 사용하는 에너지의 절감과 효율 운전은 매우 중요한 관심사항이다. 본 논문에서는 생산 플랜트의 한 공정에서 가장 빈번히 사용되는 유도전동기를 모델로 하여 실제 진단, 계측을 통하여 측정값을 얻고, 기존의 운전 중인 설비들을 고효율 기기로 교체하였을 경우의 경제성을 분석하였다. 이를 위해서 현재 운전 중인 설비와 고효율설비로 교체하였을 경우에 대하여 각각 설비들의 연간 운전비용과 자본회수계수에 의한 연간 투자비용을 계산하였고, 이를 합산한 연간 총 운용비용을 비교하여 고효율설비의 경제적 타당성을 입증하였다.

• 한국전기전자재료학회논문지
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• 제35권6호
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• pp.581-593
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• 2022

As energy depletion and environmental pollution problems are intensified, research has been conducted actively on alternative energy sources, an eco-friendly and continuous available energy conversion system. So has been organic solar cells whose efficiency is improved to 18.32%. The photoactive layer inside the solar cell is composed of a donor and a acceptor, and the combination of materials capable of effectively exchanging electrons greatly affects the efficiency of the organic solar cell. Accordingly, various researches have been conducted to improve the efficiency, and the maximum efficiency could be achieved by a solar cell with high carrier generation and low charge recombination characteristics through the introduction of a non-fullerene acceptor and material reconstruction. Organic solar cells are still difficult to commercialize due to their efficiency limitations and light stability, but if a photoactive layer consisting of a donor capable of efficiently absorbing long-wavelength light and an acceptor capable of forming an appropriate energy level is designed, the efficiency of the organic solar cell will reach 20%.

• KIEAE Journal
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• 제17권2호
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• pp.13-20
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• 2017

Meteorological data is one of the important factors in the calculation of building energy demand. The purposes of this study are to review the limitations of the typical meteorological data of ECO2 program and to create the new typical meteorological data and then analyze the building energy demands for additional regions which are not included in the existing 13 region in the ECO2 program. The extended typical meteorological data to a total of 33 regions were based on IWEC(International Weather for Energy Calculations) data files and were created in the form applicable to the building energy efficiency rating certification system. As a result of comparing the heating energy demands of a representative region with the surrounding regions in each of five regions in Korea, the variance of Cv(RMSE) ranged from 36% to 344% and MBE ranged from -32% to 190% for the whole regions. This suggests that the difference of heating energy demand may vary greatly depending on the region where the meteorological data is used and the meteorological data of more detailed regions is needed for reliable calculation of building energy demand.

• 상하수도학회지
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• 제31권1호
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• pp.13-19
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• 2017

Relatively low efficiency in anaerobic digestion process is mainly caused by unproper mixing method. In this study, tray motion type agitator was applied in actual anaerobic digestion tank in order to improve the digestion efficiency, equalize the flow velocity distribution and energy saving. The impeller of tray motion type agitator was reciprocated vertically. Gas lift type agitator and tray motion type agitator appears almost same mixing efficiency include digestion rates. However, tray motion type agitator have shown that lower energy consumption compared to the conventional gas lift type agitator. Implementation of tray motion type agitator in the anaerobic digestion tanks contributed to the stabilization of mixing environment, efficiency and energy efficiency of the tank.