• International journal of advanced smart convergence
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• 제8권4호
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• pp.26-33
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• 2019

We conducted research to evaluate economically and engineering about the synthesis of Magnesium Oxide, MgO, nanoparticles using physicochemical methods. The method used was economic evaluation by calculating GPM, BEP, PBP, and CNPV. The other method used was engineering perspective. MgO nanoparticles were synthesized by reacting Mg(NO₃)₂ and NaOH with a mole ratio 1: 2. Mg(OH)₂ formed was heated and calcined to remove water content and to oxidation to form MgO. An economic evaluation by calculating GPM and CNPV for the production of MgO nanoparticles on an industrial scale shows that the payback period (PBP) occur in the third year and profits increase each year. Tax variations show that the higher of tax, the lower profits received. When there was an increase of selling prices, the profit was greater. The variable cost used is the price of raw material. When there was an increased in the variable cost price, the payback period was longer and the profits was reduced. The benefit of this research is knowing the industrial production of MgO nanoparticles is beneficial. The function of MgO nanoparticles is a material for the manufacture of ceramics and can be used as an antimicrobial in the water filtration process.

• 설비공학논문집
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• 제23권10호
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• pp.656-661
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• 2011

The amount of water resources that can be used tend to be decreased gradually. In contrast, the rapidly increasing water consumption is a problem that need to be addressed. Renovation and equipment replacement to improve energy efficiency and to reduce expenditure for building usage is required. But the excessive initial investment cost and the prolonged of pay back period may be uneconomical choice. Water usage for cleaning the toilet bowl accounts for 27%of the total water usage. Water-saving valve that can select the amount of water for cleaning toilet bowl can be reduced expenditure. After installing water-saving valve, analysed the economic effects. Water-saving valves compared with flush valves, and researched the amount of water usage. Then analyzed for the economic effects. Water-saving valve was used 5.6 ${\ell}$/time for cleaning toilet bowl. In contrast, flush valve was consumed 8.4 ${\ell}$/time. Water-saving valve's water-saving rate was 33.3%. The initial payback period for Water-saving valve was 459.5 days. By a small investment in water saving valve, the economic benefits can be obtained.

• 설비공학논문집
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• 제24권3호
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• pp.205-211
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• 2012

Unlike the previous approaches, we analyzed for economic efficiency of renewed heating and cooling systems as the characteristics of space. The purpose of this study is to analysis the energy consumption and economical efficiency of absorption chillers and EHP systems in renovated library. It is important that equipment selection should be considering energy cost as well as space program. In recently, many EHP systems were installed in the building for reducing the energy cost and for seeking the convenience of individual control. In contrast, though absorption chillers have the disadvantage of a central control, absorption chillers are appropriate for the conditions of the library that needs simultaneous operation. The results by payback period method, show that selection of heating and cooling systems should be consider for space program and the characteristics of space.

• 전기학회논문지
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• 제61권9호
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• pp.1260-1268
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• 2012

Recently, lack of power reserve margin was observed quite often. In this paper, we studied the method to secure power source for a short time, to cut the utility power peak load, and to reduce the users electricity bills. Emergency diesel generator of an office building is to be converted into a dual-fuel engine generator which is responsible for a portion of the peak load. Compared to the conventional diesel fuel generator, the proposed dual-fuel engine is able to reduce the generation power cost by dual-fuel combustion, and it also mitigates the building's utility power peak load by charging the building's peak load. If the dead resources (a group of emergency dual-fuel engine generators), as a Virtual Power Plant, are operating in peak time, we can significantly reduce future large power development costs. We investigated the current general purpose electricity bills as well as the records of the building electric power usage, and calculated diesel engine generator renovation costs, generation fuel costs, driving conditions, and savings in electricity bills. The proposed dual-fuel engine generation method reduces 18.1% of utility power peak load, and turned out to be highly attractive investment alternative which shows more than 27% of IRR, 76 million won of NPV, and 20~53 months of payback periods. The results of this study are expected to be useful to developing the policy & strategy of the energy department.

• 전기학회논문지
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• 제67권10호
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• pp.1278-1285
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• 2018

For saving electricity bill, energy storage system(ESS) is being installed in factories, public building and commercial building with a Time-of-Use(TOU) tariff which consists of demand charge(KRW/kW) and energy charge(KRW/kWh). However, both of peak reduction and ESS special tariff are not considered in an analysis of initial cost payback period(ICPP) on ESS. Since it is difficult to reflect base rate by an amount of uncertain peak demand reduction during mid-peak and on-peak periods in the future days. Therefore, the ICPP on ESS can be increased. Based on this background, this paper presents the advanced analysis method for the ICPP on ESS. In the proposed algorithm, the representative days of monthly electricity consumption pattern for the amount of peak reduction can be found by the k­means clustering algorithm. Moreover, the total expected energy costs of representative days are minimized by optimal daily ESS operation considering both peak reduction and the special tariff through a mixed-integer linear programming(MILP). And then, the amount of peak reduction becomes a value that the sum of the expected energy costs for 12 months is maximum. The annual benefit cost is decided by the amount of annual peak reduction. Two simulation cases are considered in this study, which one only considers the special tariff and another considers both of the special tariff and amount of peak reduction. The ICPP in the proposed method is shortened by 18 months compared to the conventional method.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.592-595
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• 2009

In recent years, geothermal heat pump (GHP) systems have become increasingly popular for heating and cooling in buildings. The Standing Column Well (SCW) method is one of the most efficient GHP system. Because it use groundwater for heat transfer material. In SCW systems, water is re-circulated between the well and the building (heat pump). It is only a short time since this method has been applied in domestic. So we have to refer to the developed countries' guides and manuals of SCW. In this paper, several design and construction points of SCW method are filed. We used real operation data of SCW system at Chong-Ju Univ. site for economical efficiency analysis. As a result, the payback period of Chong-Ju Univ. site is calculated at 7.23 years.

• Ocean and Polar Research
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• 제31권2호
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• pp.167-176
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• 2009

Cobalt-rich manganese crusts on seamounts have received an increasing amount of attention as future resources for Co, Ni, Cu, and Mn. A dearth of detailed information regarding the relevant distribution characteristics, mining technologies, and ore processing technologies, however, has precluded potential evaluations of the technical and economic advantages of these crusts. In the past 4 years, Korea has undertaken a survey of the cobalt-rich manganese crusts in and around the Magellan Seamount and Mid-Pacific Mountains. This paper introduces the preliminary feasibility study of the distribution features and R&D results centered around the development of the cobalt-rich manganese crusts. The evaluation model was developed by modifying the model for the manganese nodules. In addition to considering the geological and geophysical differences between the manganese nodules and the cobalt-rich manganese crusts, an ore dressing subsystem was installed in the model. The mining subsystem is composed of a self-propelled collector--a pipeline with submersible hydraulic pumps for crust lifting. The smelting and chlorine leach method was selected for metallurgical processing. The production scales were established at 2,500t/y of cobalt metal. The production of three metals--cobalt, nickel, and copper--was considered in terms of metallurgical processing. The economic feasibility analyses demonstrated that the payback period was 11.4 years, the NPV was 36M$, and the IRR was 9.6% with the economic factors in the case of a cobalt price of US$ 25/lb. It was also demonstrated in this study that the payback period was 8.6 years, the NPV was 154M$, and the IRR was 14.0% in the case of a cobalt price of US$ 30/lb. This indicates that the approach under consideration appears to offer greater potential given the predicted metal prices.

• 에너지공학
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• 제29권2호
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• pp.68-78
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• 2020

신 기후변화협약에 따라 전 세계적으로 온실가스를 저감하는 기술개발이 활발하게 이뤄지고 있으며, 발전·송배전 분야에서 에너지효율향상에 대한 연구가 진행되고 있다. 에너지저장장치를 이용해 잉여전기를 저장하고 전기를 공급하는 운영방식에 대한 경제성 분석, 지역단위 열 병합 발전소에서 주파수조정예비력으로 에너지저장장치를 활용하는 것이 가장 수익이 높은 운영방안으로 보고되었다. 이에 본연구에서는 체코의 열병합발전소를 대상으로 에너지저장장치 설치를 위한 경제성 분석을 실시하였다. 배터리에너지저장장치의 경제성 평가에 있어 가장 중요한 요소는 수명으로 일반적으로 1일 1회 충·방전을 기준으로 보증수명은 10~15년으로 알려져 있다. 시뮬레이션을 위해 배터리와 PCS의 비율은 1:1, 1:2로 설계하였다. 일반적으로 Primary 주파수조절용의 경우 1:4로 설계를 하지만, 열병합발전소의 특성을 고려하여 최대 1:2의 비율로 설정하였으며, 각각의 비율에 맞게 용량을 1MW~10MW, 2MWh~20MWh로 시뮬레이션을 실시하여 연간 사이클 횟수를 기준으로 수명을 평가하였다. 체코의 열병합 발전소에 배터리에너지저장장치를 설치하는 사업은 현지 인프라와 전력시장을 고려할 경우 투자 회수 기간은 3MW/3MWh가 5MW/5MWh보다 유리하다. 보조금 없이 예상 구매 가격을 고려한 간단한 투자회수기간에서 약 3년, 약 5년으로 산정되었으며, 구입비용이 전체 평생 동안 비용의 중요한 부분이기 때문에 구매가격을 50 % 낮추면 약 절반 정도의 회수 기간이 단축 될 수 있지만, 3MWh와 5MWh의 규모에 경제를 통해 수익성 확보는 불가능하다. 전력시장의 가격이 50% 하락하면 투자 회수기간은 P1 모드에서는 3년, P2 및 P3 모드에서는 2년 더 길어진다. 배터리에너지저장시스템과 발전기의 결합으로 인한 절감액의 변화에 대한 민감도 분석은 전제 범위 내에서 회수 기간에 큰 영향을 미치지 않으며, 보조금 15%를 받는 기준에서 3MW 시스템의 총 비용은 66,923,000 CZK이며, 편익은 모드에 따라 244,210,000 ~ 294,795,000 CZK이며, 비용회수기간은 3~4년이다. 동일한 기준에서 5MW 시스템의 경우 총 비용은 101,320,000 CZK이며, 편익은 모드에 따라 253,010 ~ 281,411,000 CZK로 나타나며, 비용회수기간은 5~6년이다. 체코에서 배터리에너지저장시스템은 MWh당 1년에서 1.2년의 투자회수기간이 발생하는 것을 알 수 있다.

• 수산경영론집
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• 제13권1호
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• pp.85-97
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• 1982

This study involves a blending of intensive and extensive shrimp culture techniques for a hypothetical shrimp farm which uses a combination of heated raceway nurseries and extensive grow-out ponds per year. The present value method of economic analysis is used to determine economic feasibility. The biological data in this reports were obtained from published or personal communications from leaders in the field of shrimp aquaculture. The proposed system showed economic feasibility using the present value method with discount rates of 10% and 12%. The most profitable scenario, the culture of three crops of Penaeus vannamei showed a 1.26 year payback period and 120% annual average rate of return. The breakeven price was ＄1.25/1b., which is ＄1.52 less than the market price of ＄2.77. Breakeven production was 724 1bs/acre, which is 8761bs. less than the assumed 1,600 1bs/acre. All other scenarios 1.2 and 3 crops for P. stylirostris and P. setiferus showed economic feasibility also.

• 전기학회논문지
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• 제60권1호
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• pp.32-35
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• 2011

The economic value of a wind farm project is influenced by various risk factors such as wind power output and electricity market price. In particular, there is uncertainty in the economic evaluation of a wind farm project due to uncertain wind power outputs, which are fluctuated by weather factors such as wind speed, and volatile electricity market prices. This paper presents a systematic method to assess the economic value and payback period of a wind farm project using Least Square Monte-Carlo (LSMC) simulation. Numerical example is presented to validate the effectiveness of the proposed economic assessment method for a wind farm project.