• Clean Technology
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• v.26 no.1
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• pp.55-64
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• 2020

According to the Korean Renewable Energy 3020 Implementation Plan, the installation capacity of renewable energy is expected to increase whereas technology for storing excess electricity and stabilizing the power supply of renewable energy sources is extremely required. Power-to-Gas is one of energy storage technologies where electricity is converted into gas fuel such as hydrogen and methane. Basically, Power-to-Gas system could be effectively utilized to store excess electricity generated by an imbalance between supply and demand. In this study, the economic feasibility analysis of Power-to-Gas reflecting the domestic situation was carried out. Total revenue requirement method was utilized to estimate the levelized cost of hydrogen. Validation on the economic analysis method in this study was conducted by comparison of the result, which is published by the International Energy Agency. The levelized cost of hydrogen of a 100-MW Power-to-Gas system reflecting the current economic status in Korea is 8,344 won kg^-1. The sensitivity analysis was carried out, applying the main analysis economic factors such as electricity cost, electrolyser cost, and operating year. Based on the sensitivity analysis, the conditions for economic feasibility were suggested by comparing the cost of producing hydrogen using renewable energy with the cost of producing natural gas reformed hydrogen with carbon capture and storage.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.4
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• pp.255-263
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• 2009

The most concerning issue of these days is the energy crisis caused by increasing threat of dependence on imported oil and volatile market trend. Under these circumstances, the PHEV(plug-in hybrid electric vehicle) is drawing attention for the next generation's car which could give a chance to decrease the dependence on imported oil and reduce the environmental impact of vehicle. The fueling cost of PHEV, one of the core factor of decision about buying car, should be calculated in the circumstances of Korea to make sure that PHEV has competitive power in real market. The fuel cost saving of PHEV versus CV(conventional vehicle) is simulated and discussed in the condition of increasing gasoline cost, electricity rate, and city-gas rate. In conclusion, the PHEV60-FS shows the best economic feasibility when gasoline price goes up. The PHEV20 has the most stable economic feasibility as electricity rate increases. The fuel cell cogeneration system for RPG could be an alternative for charger of PHEV in the near future.

• Ocean and Polar Research
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• v.36 no.3
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• pp.289-302
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• 2014

This paper aims to evaluate the indirect economic damages to anglers of the marine recreational charter caused by marine pollution associated with the Herbei Spirit vessel, which spilled 12,547 kl of crude oil in Taean coastal areas in December 2007. In order to evaluate the indirect cost to anglers of the charter fishing, consumer surplus for charter fishing is estimated using a Poisson model (PM), a negative binomial model (NBM), a truncated Poisson model (TPM), and a truncated negative binomial model (TNBM), which account for the characteristics of count data (non-negative discrete data), for individual travel cost method (ITCM). Because of over-dispersion problem in PM and TPM, NBM and TNBM are considered to be more appropriate statistically. All parameters such as income, fishing careers, travel cost and catch that are estimated are statistically significant and theoretically valid. Based on TNBM results, consumer surplus per trip and per person was estimated to be 277 thousand won, total consumer surplus per person and per year about 2.3 million won, and the marginal effect of consumer surplus on % changes in catch rate is about 33 thousand won. The consumer surplus was converted into total indirect economic damages for aggregation which are evaluated to be 125 billion won, reflecting the number of anglers and damage rate.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.7
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• pp.491-499
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• 2007

An architectural means of optimal daylight distribution is by using so-called light shelf systems, horizontal shading and redirecting devices. The overall performance of the daylighting system can be improved by the incorporation with electric lighting control devices. This paper aims to exemplify the benefit of daylighting in term of economic consideration. In such a case a reasonable technique to compare system costs is by life-cycle costing. Stated simply, a life-cycle cost represents the total cost of a system over its entire life cycle, that is, the sum of first cost and all future costs. Four different electric lighting system designs are proposed and a lighting control system that is continuously operating according to the level of daylight in the space has been adapted. The result shows clearly that although denser layout of lighting fixtures might be more effective to interface to the level of daylight ceaselessly changeable, its economic benefit may not meet the expected criterion the reason of increased initial investment and maintenance cost for the fixtures and control devices.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.2
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• pp.258-264
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• 2010

Various kinds of ballast water treatment systems (BWTS) have been developed corresponding to reinforced IMO rules for marine environment. Some of them got the certificate of IMO and others are waiting for it. Selection of optimum BWTS is very important. Optimum BWTS means not only functional requirements but also economic efficiency. This paper presents economic analysis model for optimum BWTS according to ship type and size. In this study 10 kinds of BWTS whose initial installation cost and maintenance cost are known are analyzed based on present worth method. It is assumed that all BWTS satisfy minimum functional requirements and we need to consider different economical efficiency. Through the economic analysis we could select optimum BWTS.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.11
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• pp.621-628
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• 2009

The objectives of this study are to analyze the performance of a river water-source heat pump and to carry out economic assessment for the heat pump. The COP of the river water-source heat pump was 3-21% higher than that of the air-source heat pump because river water provides stable operating temperature compared with air temperature throughout the year. The economic analysis was carried out by comparing the initial and operating cost of the river water-source heat pump with those of the conventional air-source heat pump. The ratio of the life cycle operating cost to the life cycle cost increased with the increase of building capacity. The payback period was found to be less than 3.5 years when the capacity of the river water-source heat pump was larger than 10 RT.

• Journal of Korean Academy of Nursing
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• v.34 no.1
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• pp.191-201
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• 2004

Purpose: This study aimed to evaluate economic viability of public health center visiting nurse services for the low-income elderly with long-term care needs. Method: The sample consisted of 252 community dwelling elderly who enrolled in public health center visiting nurse services for three months or more. Data was collected on physical (ADL and IADL) and cognitive impairments of the elderly, contents and frequency of visiting nurse services, cost per visit, and costs of alternative services for long-term care. Result: The mean score of ADL and IADL levels of the elderly was 2.80.4904, which indicated these patients were mostly independent. Eighty four percent of the elderly subjects were cognitively intact. Among visiting nurse services supplied, providing assessment was 34%, followed by education and counseling 26%, medication 22%, and referral. The mean cost per visit was 17,824.1 won, which transformed into a total cost per person per year of 161,130.2 won. Comparing the cost of a visiting nurse service with those of other long-term care alternatives, the visiting nurse service was the least costly alternative, followed by an outpatient clinic, hospital based home care, and nursing home. Conclusion: Overall, the results of the study provide evidence of the economic viability of visiting nurse services for the low-income elderly among long-term care alternatives.

• KIEAE Journal
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• v.6 no.3
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• pp.11-18
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• 2006

Attention on daylighting should be focused not so much on a simple maximization of the natural light available in a space, as on improving the quality of lighting by ensuring as even but intense distribution of illumination in inner areas. An architectural means of optimal daylight distribution is by using so-called light shelf systems, horizontal shading and redirecting devices. The overall performance of the daylighting system can be improved by the incorporation with electric lighting control devices. This paper aims to exemplify the benefit of daylighting in term of economic consideration. In such a case a reasonable technique to compare system costs is by life-cycle costing. Stated simply, a life-cycle cost represents the total cost of a system over its entire life cycle, that is, the sum of first cost and all future costs. Four different electric lighting system designs are proposed and a lighting control system that is continuously operating according to the level of daylight in the space has been adapted. The result shows clearly that although denser layout of lighting fixtures might be more effective to interface to the level of daylight ceaselessly changeable, its economic benefit may not meet the expected criterion the reason of increased initial investment and maintenance cost for the fixtures and control devices.

• Journal of Korean Institute of Industrial Engineers
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• v.21 no.3
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• pp.387-396
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• 1995

For situations where there are several markets with different profit/cost structures, an economic two-sided screening procedure using a correlated variable is developed. It is assumed that the performance variable and the screening variable are jointly normally distributed. A profit model is constructed which involves selling price, cost incurred by imperfect quality, and screening inspection cost. Methods of finding the optimal screening procedure are presented and numerical examples are given.

• Korean Management Science Review
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• v.13 no.3
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• pp.37-48
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• 1996

This paper presents an Economic Lot Scheduling Problem in which controllable production rates are considered. We also take into account the controllable range of production rate (i.e., maximum and minimum production rate) of each product and the mold cost which varies to the production rate. A mathematical model is developed and an iterative solution procedure is suggested. The objective of this problem is to minimize production related cost and the decision variables are common production cycle time and production rate of each product. As a case study, we adapted this model to the press machine of a company.