• ETRI Journal
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• 제16권3호
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• pp.11-26
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• 1994

In Korea, the price schedule for local telephone combines two-part tariffs and peak-load pricing subject to rate-of-return (RoR) regulation. Although the effect of RoR regulation on two-part tariffs or peak-load pricing has been separately analyzed by many authors in some detail, the behaviour of regulated firm under combined two-part and peak-load pricing has not been studied until now. This paper examines the effect of regulation on the rate structure and welfare under combined two-part and peak-load pricing.

• 한국지열·수열에너지학회논문집
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• 제5권1호
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• pp.13-17
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• 2009

The river water heat source heat pump has the advantage in the performance compared to air source heat pump. In this study, an experimental study on a 2-stage heat pump, which is designed to utilize a river water heat source, were carried out. Generally, a heat pump is designed for maximum capacity rate, but it actually operates at part load condition in most cases. Therefore, an information on the part-load characteristic is very important in view of the system overall performance. In this study, part-load performance tests of a R134a 2-stage compression heat pump were carried out over the river water and supply heating water temperature changes.

• 대한기계학회논문집B
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• 제26권8호
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• pp.1164-1171
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• 2002

This study analyzed the dependence of part load performance of simple cycle gas turbines on their design performance. Various parametric calculations were carried out to examine effects of design temperature ratio, pressure ratio and component efficiencies using a simplified analysis. In addition, a more practical analysis was done for realistic design conditions with the aid of a comprehensive performance analysis program. The results show that gas turbines with higher design performance exhibit less efficiency degradation during part load operation. The influence of power control method (fuel only centre) and air flow control) on part load performance was examined as well.

• 대한기계학회논문집B
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• 제20권7호
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• pp.2409-2420
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• 1996

This paper describes the development of a general program for the design and part load performance analysis of single-shaft-heavy-duty gas turbines. Efforts are made to fully represent the real component features by the characteristic models and special emphasis is put on the modeling of cooled turbine stages. The design analysis routine is applied to simulate the performance of current gas turbines and its appropriateness for system analysis is validated. Meanwhile, the component parameters of real engines which describe the technology level are obtained. The program is extended to predicting the part load operation of gas turbines with the aid of models for the off-design characteristics of compressor, turbine and other main components. Part load simulation can be carried out only with limited numbers of input data. It is demonstrated that the program accurately estimates the part load characteristics of real turbines.

• 대한기계학회논문집B
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• 제32권11호
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• pp.849-855
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• 2008

The paper addresses modeling and analysis of the part load performance of a hybrid fuel cell system integrating a polymer electrolyte membrane fuel cell(PEMFC) and a gas turbine(GT). The system is a pressurized one where the working pressure of the PEMFC is higher than the ambient pressure. In addition to the two major components, the system also includes auxiliary parts such as a steam reformer, a humidifier, and afterburner and so on. Based on design analysis, component off-design models are incorporated in the analysis program and part load operation is simulated. The mode for the part load operation of the PEMFC/GT hybrid system is a variable rotational speed operation. The operating characteristics and variations in the system efficiency and component performance parameters at part load are analyzed.

• 설비공학논문집
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• 제27권9호
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• pp.455-462
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• 2015

Residential buildings account for a significant portion of the total building-energy usage in Korea, and a variety of research studies on the domestic boiler have therefore been carried out; however, most of these studies examined the boiler itself, whereby the part-load ratio characteristics and the corresponding gas-energy consumption patterns were not analyzed. In this study, the part-load ratio and operating characteristics of a domestic gas boiler were analyzed within a residential building equipped with a radiant floor-heating system; in addition, the energy consumption between condensing and conventional boilers was comparatively analyzed. Our results show that significant portions of the total operating hours, heating load, and energy consumption are in the part-load ratio range of 0 through 40%, whereby the energy consumption was significantly affected by the boiler efficiency under low part-load conditions. These results indicate that the part-load operation of a boiler is an important factor in residential buildings; furthermore, replacing a conventional boiler with a condensing boiler can reduce annual gas-energy usage by more than 20%.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2000년도 추계학술대회 학술발표 논문집
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• pp.393-398
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• 2000

In this paper, we propose an Intelligent Monitoring Network System(IMNS) for the truck scale balance system. Truck scale balance system consis of three parts; Load cell part, Indicator part, and Junction box part. IMNS is attached to Junction box in truck scale balance system. Even if Load cell have been some problems, a truck scale balance system still has been run to determine, the values involved error. Therefore prosed system is has concentrated on Load cell part. Other Parts have been changed a portion of circuit for monitoring system.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(3)
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• pp.41-44
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• 2000

In this paper, we propose an Intelligent Monitoring Network System(IMNS) for The truck scale balance system. Truck scale balance system consis of three parts； Load cell part, Indicator part, and Junction box part. IMNS is attached to Junction box in truck scale balance system. Even if Load cell have been some problems, a truck scale balance system still has been run to determine, the values involved error. therefore prosed system is has concentrated on Load cell part. Other Parts have been changed a portion of circuit for monitoring system.

• 에너지공학
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• 제17권3호
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• pp.161-166
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• 2008

본 논문은 배열회수보일러에서 부분부하 운전이 과열기 열성능에 미치는 영향을 조사하였다. 첫 단계로 가스터빈 최대부하와 부분부하 운전시 배열회수보일러 형태에 따른 가스터빈 배가스의 유동 특성을 전산유체해석을 통해 조사하였다. 다음으로는 수직형 배열회수보일러 과열기 튜브관군의 가스터빈 최대부하와 부분부하 운전 시 온도분포를 전산유동해석 결과를 이용해 계산하였으며, 이 결과와 실제 발전소 측정을 통해 획득한 온도분포 결과를 비교하였다. 마지막으로 부분부하 운전이 과열기 열성능에 미치는 영향을 살펴보았으며, 또한 부분부하 운전시에 유동의 불균일 현상을 제거할 수 있는 장치를 고안하였다.

• 설비공학논문집
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• 제28권4호
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• pp.137-144
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• 2016

Commercial buildings account for a significant proportion of the total building energy use in Korea, and cooling energy, in turn, accounts for the largest proportion of total energy consumption in commercial buildings. Under this circumstance, chiller staging is considered to be a reasonable and practical solution for cooling energy saving. In this study, the part-load ratio and the operating characteristics of a vapor compression chiller were analysed within an office building. In addition, energy consumption among different chiller staging schemes was comparatively analysed. As a result, significant proportions of total operating hours, cooling load and energy consumption turned out to be in the part load ratio range from 0% through 50%, and thus energy consumption was significantly affected by the chiller COP at low part-load conditions, indicating that the chiller operation at the part-load is an important factor in commercial buildings. In addition, utilizing a sequential chiller staging scheme can reduce the annual cooling energy usage by more than 10.3% compared to operating a single chiller.