• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.515-518
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• 2007

Because of their low operating and maintaining costs, ground-source heat pump(GSHP) systems are an increasingly popular choice for providing heating, cooling and water heating to public and commercial buildings. Despite these ad- vantages and the growing awareness, GSHP systems to residential sectors have not been adopted in Korea until recently. A feasibility study of a residential GSHP system was therefore conducted using the traditional life cycle cost(LCC) analysis within the current electricity price framework and potential scenarios of that framework. As a result, when the current residential electricity costs for running the GSHP system are applied, the GSHP system has weak competitiveness to conven- tional HVAC systems considered. However, when the operating costs are calculated in the modified price frameworks of electricity, the residential GSHP system has the lower LCC than the existing cooling and heating equipments. The calculation results also show that the residential GSHP system has lower annual prime energy consumption and total pollutant emissions than the alternative HVAC systems considered in this work.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.8 no.3
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• pp.12-18
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• 2012

The purpose of this study is to make an economic analysis(Life cycle cost) of selecting optimal air conditioning system for a research building which is 8 stories with a total floor area of $32,010m^2$. Energy consumptions of three proposed air-conditioning systems(Alt-1,2,3) that reflect the government green-growth policy are calculated and compared. The results show that life cycle cost of Alt-3(Ventilation DX AHU+EHP) is less than Alt-1(EHP+ventilation DX AHU) by 5.1%, and Alt-2(Absorption chiller/heater+EHP) by 34.3%. Annual energy consumption of Alt-3 is less than Alt-1 by 9.9%, and Alt-2 by 37.4%. Annual $CO_2$ emission of Alt-3 is less than Alt-1 by 9.9%, and Alt-2 by 0.2%.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.459-465
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• 2007

This study was conducted to calculate the LCC of a apartment complex with a type of heating system, district heating and cogeneration system. For the purpose of analyzing LCC according to size of apartment complex, 500, 1,500 and 4,000 houses of model apartment selected. This research performs design of heating system and the life cycle cost analysis including an initial cost, energy cost, maintenance and operation cost, replacement cost and renovation cost during the project period(15years). According to the calculated results, 1) Initial cost of cogeneration system with 500, 1500 and 4000 houses is higher than district heating system each of 20%, 13%, 12%. 2) In case of cogeneration system, the payback period by electric generation is 5.21, 4.92 and 4.47 years and saving cost was calculated 29 billion won, 94 billion won and 262 billion won after payback period. 3) Cogeneration system LCC was 1.12, 1.07 and 1.06 times larger than district system with the size of apartment complex. According to the case of this study district heating system is more efficient than cogeneration system in terms of the reduction of LCC. 4) Gas Engine Co-generation System is more efficient than other systems because it can collect progressive part from electric charge progressive stage system. However, the efficiency is decreasing because of raising of fuel bills(LNG) and lowering of power rate for house use. Especially the engine is foreign-made so the cost of maintenance and repair is high and the technical expert is short. 5) District heating is also affected by fuel bills so we should improve energy efficiency through recovering of waste heat(incineration heat, etc.). Also, we should supply district cooling on the pattern of heat using of let the temperature high in winter and low in summer.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.54-59
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• 2008

The poor maintenance and management of HVAC systems finally lead to the shortening of the life expectancy and result in the increase of operating costs and energy consumptions due to low efficiencies. Also, it is essential to try to develop ways to adequately maintain and to use the building facilities efficiently in order to preserve earth environment and the limited resource. In this study, an analysis on the maintenance and management cost for HVAC systems was carried out with the capacity of equipment. Besides, the LCC(Life Cycle Cost) based analysis was carried out to verify the effect of the doing maintenance and management. As the results, the case of the good maintenance and management is able to save LCC to 11 % than the case of the poor method.

• Plant Journal
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• v.15 no.2
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• pp.46-55
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• 2019

This paper presents a LNG Liquefaction cycle configuration using two stages of methane expansion (i.e. spliting into two stages as warm & cold to generate an additional inflection point within a cold composite curve) and a single stage of nitrogen expansion to improve the efficiency of the conventional Methane & Nitrogen Expansion Cycle. In comparison with Double Nitrogen Expansion Cycel and Methane & Nitrogen Expansion Cycle, the cycle efficiency has increased approximately from 13.92 and 13.13 to 12.08 kW/ton/day (8~15% efficiency increase). A Life Cycle Cost (LCC) analysis based on Net Present Value (NPV) also show an improvement in therms of project NPV, against a minor increment of a CAPEX.

• 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.

• 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.

• 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.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.379-389
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• 2010

It is very important to determine a target probability of failure in reliability based design such as an allowable factor of safety in working stress design because they are indices to judge the stability of structures. We have carried out reliability analyses of nationwide gravity type quay walls and found that sliding and foundation failures of quay walls were dominant failure modes for every case of loads. And a target probability of failure for bearing capacity of foundation of quay wall was also determined in this study. Of several approaches which have been suggested until now, a couple of reasonable approaches were used. Firstly, in order to consider the safety margin of structures which have been executed so far, the reliability levels of existing structures were assessed. And then a mean probability of failure for the quay walls was estimated. In addition, life cycle cost(LCC) analyses for representative structures were performed. Probabilities of failure for several quay walls were calculated with changing the width of each quay wall section. LCC of quay wall which is requiring case by case during the service life was evaluated, and also the optimum probability of failure of quay wall which minimizes LCC was found. Finally, reasonable target probabilities of failure were suggested by comparing with mean probability of failure of existing structures.

• International Journal of Highway Engineering
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• v.14 no.5
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• pp.123-132
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• 2012

PURPOSES: This study is to investigate the consideration which relates with a disaster from route alignment process and proposed the method it will be able to evaluate a disaster danger fixed quantity. METHODS: Use the landslide disaster probabilistic map of GIS based and in about landslide occurrence of the route alignment at the time of neighboring area after evaluating a risk fixed quantity, it compared LCC expense in about each alternative route. It developed the system it will be able to analyze a LCC and a disaster risk in about the alternative route. In order to verify a risk analytical algorithm and the system which are developed it selected national road 59 lines on the demonstrative route and it analyzed a disaster risk. RESULTS: Demonstrative route not only the disaster risk to be it will be able to compare a disaster risk fixed quantity like the economical efficiency degree in compliance with LCC expense productions it compared and there being the designer will be able to decide the alternative route, it confirmed. CONCLUSIONS: Roads can be designed by considering occurs repeatedly landslides and debris flow caused by disasters in advance and expect to be able to effect that can reduce the overall cost to recover losses caused by the disaster, and temporally loss is expected.