• Proceedings of the SAREK Conference
• /
• 2006.06a
• /
• pp.607-612
• /
• 2006

A pressure-type rapid automatic filter of 2000mm diameter and 170 ton/h filtering capacity was fabricated. In case of no external impurity inflow, the turbidity removal efficiency on raw water was experimented and the numbers of impurities of each sizes were analyzed by particle counter. As the result of circulated filtering, the raw water of 40 NTU was filtered to 0.44 NTU and the numbers of impurities above $1{\mu}m$ were removed by approximately 95%. With the filtering efficiency experimented and the mathematical method, the turbidity change of circulation water were calculated according to the inflow rate of external impurity and water treatment method of blow-down or filtering. The cost of blow-down water was calculated from above results. And simple payback period for this filter is calculated as about one year. Nowadays, as the cost of water is continuously increasing and environment regulations will be more strict, the water quality control using this filter will be expected to satisfy the user requirement.

• Land and Housing Review
• /
• v.11 no.4
• /
• pp.15-26
• /
• 2020

This study analyzes the Domestic Economic Ripple Effect (DERE) of the Donghae-Bukpuseon Railway (DBR). Input-Output Analysis and Scenario Analysis are employed. First, the future demand is approximately 6.86 billion people, 1.4 billion tons of logistics, and future forecast production is 1.2 trillion won for passengers, and 0.15 trillion won for logistics. Second, the production inducement (PI) coefficient of the railway industry is 2.080, the value-added inducement (VAI) coefficient is 0.680, the import inducement (II) coefficient is 0.32 and the employment inducement (EI) coefficient is 6.45. Third, for the DERE, PI is 2.846 trillion won, VAI is 0.939 trillion won, II is 0.446 trillion won, and EI is 8,737 people/1 billion won. Fourth, PI is approximately 2.8 trillion won, and the payback period is 35 years. Scenario 1 (a 50% increase in the demand for tourism) takes approximately 27 years, Scenario 2 (an 100% increase), 20 years, and Scenario3 (an 150% increase), 16 years. The successful way of the DBR is to enlarge the linkage effect of trans-railways for which international cooperation and agreements are needed. Also, even if the DBR is isolated due to worsening inter-Korea relations, the development of tourism resources is important for public investment feasibility.

• Journal of the Architectural Institute of Korea Structure & Construction
• /
• v.34 no.11
• /
• pp.81-87
• /
• 2018

Among various types of geothermal heat pump systems, Vertical Closed-Loop Geothermal Heat Pump (VGSHP) has received increasing attention due to a variety of advantages such as the potential to be installed in a relatively small space and improved energy efficiency. In this research, the performance of VGSHP system coupled with heat storage tank was evaluated, by analyzing operational behavior of heat storage tank, the variations of heat pump energy performance due to the connection with heat storage tank, part load ratios characteristics of heat pump and the corresponding energy cost, compared to chiller and boiler based conventional system. The results of this study showed that the VGSHP system coupled with heat storage tank showed an energy saving effect of about 18% for cooling and about 73% for heating, and annual heating/cooling energy cost reduction of 43,000,000 KRW ($ 39,000), compared to the conventional air conditioning system. In addition, after considering both energy cost and initial investment cost including equipment, installation and auxiliary device expenses, payback period of approximately 11.8 years was required.

• Advances in Energy Research
• /
• v.8 no.1
• /
• pp.59-71
• /
• 2022

Increasing cost of electricity due to rising price of fuel is one of the local community's main issues. In this research, switching of grid dependent system to the grid-tied Photovoltaic (PV) system with net metering for a residential building is proposed. The system is designed by considering the maximum energy demand of the building. The designed system is analyzed using RETScreen on technical, economic and environmental grounds. It is found that the system is able to produce 12,000 kWh/year. The system is capable to fulfill the electricity demand of the building during day time and is also capable to sell the energy to the local grid causing the electric meter to run in reverse direction. During night time, electricity will be purchased from grid, and electric meter will run in the forward direction. The system is economically justified with a payback period of only 3 years with net present value of PKR. 4,758,132. Also, the system is able to reduce 7.2 tons of CO₂ not produced in the entire life of the project.

• The Journal of the Korea Contents Association
• /
• v.18 no.9
• /
• pp.584-593
• /
• 2018

The startup, which is a common noun to start a small business, has been recently one of main targets for policymakers due to its important role for job creation and considerable potential for sustainability of an economy. However, technological entrepreneurship decreased by 5.0% p from 2013 to 2016. The revitalization of entrepreneurial investment promoted by the government is mainly supported in fruitable venture companies at grow stage or 2~3 years before IPO through venture capital firms and angel funds. It is far from an investment at start-up. It is therefore necessary to motivate private investment to be active in the private start-up sector. In addition, the start-up investment requires institutional support and government support to meet the expectations of investors about the possibility of payback and profitability of private investment invested in the founding period. As a small entrepreneur at a comparably early stage in the lifecycle of business, investments for the startup are generally made by informal investors such as family, friends and fools, and their decision making processes are relatively non-programmed compared with ones for listed corporales such as venture capital and angel fund agency. This study focuses on analyzing decision making factors in investment, and verifying an impact of such factors, specifically the possibility of investment payback and investment profitability, in a decision-making process for the startup especially at the very early stage.

• Korean Journal of Agricultural Science
• /
• v.24 no.2
• /
• pp.170-181
• /
• 1997

The number of modernized green houses have been increased to produce high quality and high-payoff farm products. The unit investment costs per pyeong($3.3058m^2$) for building a glass house was estimated at 449 thousand won. On the other hand, the unit prices for the PC house with iron frame and the vynil house with automatic control system were revealed 365 thousand won and 93 thousand won respectively. The main objective of the study was to identify the financial feasibility of the green house investment prevailed in rural area. At present, some farmers have selected the green house without any consideration of profitability of crops and accessiblity of their fanning practices and technology. For the soundness of green house cultivation and management, the indices of finacial efficiency for the modernized green houses were necessary. The decesion making criteria such as NPV(Net Present Value), IRR(Internal Rate of Return), B/C Ratio and Payback Period were analyzed for the individual high investment facilities considering the present farmer's technology and on-farm benefits and costs. The results of the feasibility analysis of green houses were as follows: 1. In case of 100% private burden of the investment costs, NPV revealed only positive value for the vinyl house with automatic system and IRR for the house was also estimated at more than 10% and B/C Ratio was amounted to more than 1.0. On the other hand, the other glass and PC houses showed negative NPV and unacceptable B/C ratio and IRR. 2. In case of the following terms and conditions as 50% Government subsidy, 20% loans and 30% farmers burden of the total investment cost, all the green houses showed acceptable IRR, B/C Ratio and NPV. 3. The financial feasibility of the glass house was acceptable in tomato cultivation rather than in cucumber cultivation. The payback periods of cucumber were represented as 8.9 years for glass house, 8.5 years for PC house and 4.1 years for vinyl house with automatic system respectively. In conclution, the glass and PC house cultivation of high value vegetables were only acceptable under the Goverment subsidy and loan systems from the view point of farmer's financial situations. On account of the unacceptable economic rate of return, the government subsidy and loan policy for glass house cultivation should be transfered to the vinyl and pc houses in the future.

• Ocean and Polar Research
• /
• v.38 no.3
• /
• pp.225-234
• /
• 2016

This project sought to conduct an economic feasibility study regarding the commercial production of bio-hydrogen by the marine hyperthermophilic archaeon, Thermococcus onnurineus NA1 using carbon monoxide-containing industrial off-gas. We carried out the economic evaluation of the bio-hydrogen production process using the raw material of steel mill by-product gas. The process parameter was as follows: $H_2$ production rate was 5.6 L/L/h; the conversion of carbon monoxide was 60.7%. This project established an evaluation criterion for about 10,000 tonne/year. Inflation factors were considered as 3%. The operating costs were recalculated based on prices in 2014. The total investment required for development was covered 30% by capital and 70% by a loan. The operation cost for the 0.5-year test and integration, and the cost for the first three months in the 50% production period were considered as the working capital in the cost estimation. The costs required for the rental of office space, facilities, and other related costs from the construction through to full-scale production periods were considered as continuing expenses. Materials, energy, waste disposal and other charges were considered as the operating cost of the development system. Depreciation, tax, maintenance and repair, insurance, labor, interest rate charges, general and administrative costs, lubrication and miscellaneous expenses were also calculated. The hydrogen price was set at US$ 4.15/kg for the economic evaluation. As a result, the process was considered to be economical with the payback period of 6.3 years, NPV of 18 billion Won and IRR of 26.7%.

• Journal of Biosystems Engineering
• /
• v.38 no.4
• /
• pp.287-294
• /
• 2013

Purpose: Greenhouses for a protected horticulture covered with a plastic or glass are easy to have weakness in a heat loss by deterioration, damage, poor construction, and so on. To grasp the vulnerable points of heat loss of the greenhouses is important for heating energy saving. In this study, an on-site heat loss audit and energy consulting system were developed for an efficient energy usage of a greenhouse. Method: Developed system was mounted with infrared thermal and visual cameras to grasp the heat loss from the greenhouse quickly and exactly, and a trial calculation program of heating load of greenhouse to provide farmers with the information of heating energy usage. Results: Developed system could print out the reports about the locations and causes of the heat losses and improvement methods made up by an operator. The mounted trial calculation program could print out the information of the period heating load and fuel cost according to the conditions of greenhouse and cultivation. The program also mounted the databases of the information on the 13 horticultural energy saving technologies developed by the Korea Rural Development Administration and simple economic analysis sub-program to predict the payback period of the technologies. Conclusion: The developed system was expected to be used as the basic equipment for an instructors of district Agricultural Technology and Extension Centers to conduct the energy consulting service for the farmers within the jurisdiction.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.40 no.4
• /
• pp.129-136
• /
• 2017

Climate change is the biggest environmental issue of our times. A variety of activities to reduce greenhouse gas emissions have been in progress to observe the Kyoto Protocol. Especially, the Energy Target Scheme is created to reduce greenhouse emission with the supervision of Korean government. This includes Green-house Gas Information Systems to promote activities in the private sector to reduce green-house gas emissions, to cut a cost of energy use, and to reduce GHG emissions. Also, the system has calculated the amount of greenhouse gases. Without any additional investment, 2.75% savings are increased over the previous year. In service sector, a cooperation of customers and employees is necessary. A reduction of GHG emissions requires a proper service organization, considering an amount of investment and payback period. Without any additional investment or replacement, employees can save energy easily turning off ventilation systems an hour before employees' departure, installing timers to turn off water purifiers and vending machines after some period of no use. The Green-house Gas Information System is similar to that of Environmental Management System. However, the Excel is the best program to calculate an amount of green-house gas emissions, and to assess for a reduced amount of GHG emissions. A goal of this research is to propose a practical method in the private sector to calculate an amount of green-house gases. The Green-house gas Information System based on Excel spreadsheet gives standards for good evaluation. The greenhouse gas information system establishes and executes the policies and objectives related to greenhouse gas emissions Similar to ISO 14001 environment management system structures, the advantages of using simplified Excel Sheet for calculating GHG emissions and reducing GHG emissions are easy to access.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.66 no.12
• /
• pp.1905-1912
• /
• 2017

In recent years, Ulaanbaatar, a capital of Mongolia has witnessed major problem that air quality reaches hazardous level during the winter season. Coal combustion for heating of every house in "Ger" district is main reason. One way to reduce the air pollution is mass usage of electric heater. However, there are several difficulties such as overload and degradation of transformers and other equipment used in distribution and transmission systems as well as power shortage occurrence in evening peak period due to residential consumption. This study aims to contribute for solving the air pollution and power shortage problem in Mongolia. One possible solution could be distributed generation (DG) with photovoltaic (PV) penetration. In this study, PV with energy storage (ES) hybrid system to reduce peak load is analyzed. We proposed the suitable structure of PV-ES hybrid for Mongolian household, and suggested several operation scenarios. Optimal operation algorithm is carried out based on a comparison aspect from economical, grid impact and PV penetration possibility. The economic analyse shows annual income of 520USD, and has a payback period of 8 years for selected scenario. The proposed PV-ES system structure is verified by experimentation set on the building rooftop in city center. The suggested scenario is planned to apply for system in further research.