• 설비공학논문집
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• 제16권1호
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• pp.26-33
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• 2004

In general, an absorption chiller or heat pump is operated under the constant cooling water flow rate condition even though the system works with a partial load. The objective of this paper is to study the effect of the cooling water flow rates and the temperature of cooling water on the system performance to find the energy saving methode for the partial load operation of the double effect $H_2O$/LiBr absorption chiller. It is found that the performance of the system is sensitive to the temperature of cooling water than the cooling water flow rate, so the decrease of the performance due to reducing the cooling water flow rate can be overcome with the reduction of the cooling water temperature by 1$^{\circ}C$. The flow rate of the cooling water flow rate ranges from 50％ to 100％ of the flow rate at normal conditions with a partial load. It is also found that the operation cost of the cooling water pump and the cooling tower can be reduced by 23％.

• 에너지공학
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• 제28권2호
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• pp.47-54
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• 2019

복합화력발전소 에너지절감 사업으로 폐열회수용 흡수식 히트펌프가 설치됨에 따라 부분부하(Partial Load)에서의 성능 데이터 확인을 위해 성능시험을 실시하였다. 부분 부하에서 히트펌프 가동에 따른 운전 데이터 변화는 다음과 같다. 기기냉각수(CCW) 배열 및 배열회수열교환기(HRSG)로부터 공급되는 저압증기(LP STM)의 일부가 히트펌프의 열원으로 공급되므로 지역난방열 생산이 증대된다. 그러나 증기터빈으로 공급되는 저압증기의 유량감소에 따라 증기터빈 출력이 감소된다. 또한 고압 지역난방열교환기(HP-DH) 및 저압 지역난방열교환기(LP-DH)로 공급되는 고압터빈(HPT) 배기증기의 유량 저하에 따라 HP-DH 및 LP-DH의 열생산량도 감소한다. 부분부하에서는 정격부하 대비 히트펌프에 운전에 따른 터빈 출력 저하가 큰 것으로 나타났으며, 이에 따라 부분 부하에서는 발전소 전체의 열 생산 증가량, 전기출력 감소량을 종합적으로 고려하여 히트펌프 운전 여부를 결정해야 한다.

• 플랜트 저널
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• 제4권3호
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• pp.60-65
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• 2008

Power plant industry has been developed at high-capacity, high-technology, and innovation. Steam turbine became the most useful equipment that dominate more than 50% of all the world electricity production. And developed new materials of the turbine blade and extended length of the turbine last blade brought reform in steam turbine performance upgrade. In this paper, when do partial load driving in high-capacity steam turbine, optimum driving method found whether there is something. In operating steam turbine, there is a lot of loss from secondary wake and throttle of the 1st stage nozzle by the biggest leading factor that load fluctuation affects in high-pressure steam turbine performance. Effect of internal efficiency by 1 stage nozzle is the biggest here, but here fluid flow and flow analysis were not yet examined closely definitely. So, Analyzed design data and acceptance performance test result to applying subcritical pressure drum type 560 MW, supercritical-pressure once through type 500 MW, and 800 MW steam turbines actually. In conclusion, at partial load driving, partial arc admission(PAA) is more efficient than full arc admission(FAA) efficiency. This is judged by because increase being proportional with gross energy of stream that is pressure - available energy if pressure of stream that is flowed in to the turbine increases, available energy becomes maximum and turbine efficiency improves. Therefore, turbine performance is that preview that first stage performance fell if decline is serious in partial load because first stage performance changes according to load.

• 동력기계공학회지
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• 제18권6호
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• pp.99-105
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• 2014

This paper presents a comparison of operating characteristics for industrial water cooler with variation control methods. The performance analysis regarding the characteristics of condensation capacity, evaporation capacity, compressor load, COP of an on-off type cooler, a hot gas-bypass control type cooler and an inverter control type cooler with respect to the system load is reviewed, respectively. The primary results are as following: the variation of required compressor load of an on-off type cooler with respect to load is 5%, that of hot gas-bypass type is 18% and 66% for an inverter control type cooler. As the result shows, an inverter control type yields relatively huge difference of required compressor load compared to other types of control system. In terms of partial load, COP of an inverter control type cooler presents the highest value, and is considered as the optimized type for the used of the system involving frequent partial load.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.275-278
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• 2006

A steam turbine is one of propulsion systems of a LNG carrier, which consists of high pressure (HP) and low pressure (LP) turbines. In order to obtain high power, each one has the form of a multi-stage turbine. Especially, the first stage of a HP turbine is Curtis stage and uses partial admission considering the turbine efficiency. The performance of a HP turbine can be predicted by a mean-line analysis method, because the relatively large value of hub-tip ratio makes the three-dimensional losses small. In this study, a performance analysis method is developed for a multi-stage HP turbine using Chen's loss model developed for the transonic steam turbines. To consider the feature of partial admission, different partial admission models are reviewed, This analysis method can be used in partial load conditions as well as full load condition. The calculation results are also compared with the CFD results about some simple cases to check the accuracy of the program. Performance of two HP turbine models are calculated, and the calculation results are compared with the designed data. The comparison shows the qualitative performance analysis result.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3288-3293
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• 2007

Compressed natural gas has good potential for alternative vehicle fuel due to its economical and clean characteristics. However, the composition of natural gas based on production location is known to affect performance and emissions of CNG engine. Thus, the objective of this paper is to clarify the effect of fuel composition on combustion and emissions of CNG engine. This paper presents combustion characteristics obtained from running a 2.5L, 4-cylinder CNG engine retrofitted IDI diesel engine with engine dynamometer. BSFC, emissions, fuel consumption and combustion pressure were measured under steady state operating conditions especially at partial load for CNG engine. Based on the experimental results, we found that CNG composition affects engine performance, fuel conversion efficiency and burning rate.

• 플랜트 저널
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• 제18권2호
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• pp.32-40
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• 2022

본 연구에서는 부분부하 운전 시 가스터빈의 공기량 조절에 따른 열병합 발전의 운전데이터 변화를 알아보았다. 가스터빈 부분부하 80%시 시뮬레이션 한 결과 입구가이드베인을 최대 24% 추가로 닫을 수 있었고, 압축기 공기량은 66.11 kg/s 감소, 배기가스 온도는 52℃ 상승시킬 수 있었다. 부분부하 90%는 입구가이드베인을 최대 12% 추가로 닫을 수 있었고, 압축기 공기량은 33.33 kg/s 감소, 배기가스 온도는 23℃ 상승 시킬 수 있었다. 열부하 추종운전 시 부분 부하 80%에서 출력을 최대 5.68 MW 상승, 복합발전 효율을 0.73% 상승, 열병합발전 효율을 1.81% 상승 시킬 수 있었고, 부분부하 90%에서 출력을 최대 2.55 MW 상승, 복합발전 효율을 0.32% 상승, 열병합발전 효율을 0.72% 상승 시킬 수 있었다.

• 에너지공학
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• 제24권3호
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• pp.48-54
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• 2015

중앙집중식 냉방 시스템을 적용하고 있는 대형 빌딩이나 플랜트 설비들의 경우 부하 증설 및 피크부하에 대응하기 위한 여유율을 반영한 설비 설계 및 시공이 이루어지고 있다. 이는 부분부하가 걸리는 기간 동안에는 설비의 저부하 운전으로 인한 장비의 효율 저하와 에너지 과소비의 원인이 된다. 본 연구는 부분부하에 효율적으로 대응할 수 있도록 냉방플랜트 최적 유량제어를 통한 에너지 절감 방안에 대한 연구로서 냉방플랜트 에너지 성능 분석 프로그램을 이용하여 냉방 부하를 분석하고, 최적 유량제어 시스템을 제안하여 그 에너지 성능을 비교 평가하는 것을 목적으로 한다. 성능 분석 결과 냉방플랜트 최적 유량제어 시스템 적용 시 기존 에너지 사용량 대비 약 17%의 전기에너지 절감이 가능하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제28권7호
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• pp.1082-1091
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• 2004

Analyzed Parametrically was an internal combustion engine combined with gas turbine the cycle of which is splitted into compression side cylinder and expansion side one, and heat adding of which is during constant volume pressure, temperature process. The advantages of each measures were analyzed by means of thermal cycle diagram. The thermal efficiency of partial load cutting off firstly isothermal heat adding and secondly isobaric heat adding also was analyzed The authors suggested some potentials about the performance as for thermal efficiency, mean effective pressure and reducing emissions and noise supposed were the operating parameter of the engine set to some values and were some problems solved.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.170.1-170.1
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• 2010

Performance of water-to-air heat pump using raw water has been analyzed under part load heating operation in March, 2010. The water source heat pump of 30 RT was installed for 24 hours cooling and heating ventilation, and the gravity inflow water from Daechung dam is used as the heat source. The daily averaged water and air temperatures are $5.7^{\circ}C$ and $9.9^{\circ}C$ respectively, and the heat pump is operated under part load condition for 7.5 hours in 24 hours. The daily averaged heat pump COP calculated with heat transferred from the brine water is 2.49 and the monthly averaged COP is 2.25 in March. Based on the database of the California Energy Commission, the monthly averaged COPs of air source heat pumps installed in U.S.A. are 1.97 in March and 2.03 in April. Therefore it is confirmed again that the performance of the heat pump using raw water is better than that of air source heat pumps.