• 에너지공학
• /
• 제9권2호
• /
• pp.95-101
• /
• 2000

The purpose of this study is to find plant utilities capacity for economical operation of combined heat & power by reducing energy expenditure. Using a numerical simulation program CHPSIM, a comparative analysis of additional heat expenditure (AHE) of combined heat & power plant in relation to size of district heating has been performed within the comparison of the difference capacity of gas turbine and steam turbine . As a results, if a 105.2MW gas turbine (exhaust gas temp ; 540$^{\circ}C$) installed in CHP plant can reduced 17-18% yearly the AHE than 75MW gas turbine (520$^{\circ}C$) installed. If a 130-150MW gas turbine (560-580$^{\circ}C$) installed, can reduced 34.7-35.8% of the yearly AHE.

• 한국재료학회지
• /
• 제21권7호
• /
• pp.364-370
• /
• 2011

Currently, there are two main issues regarding the development of core technologies in the automotive industry: the development of environmentally friendly vehicles and securing a high level of safety in the event of an accident. As part of the efforts to address these issues, research into alternative materials and new car body manufacturing and assembly technologies is necessary, and this has been carried out mainly by the automotive industries. Large press molds for producing car body parts are made of cast iron. With the increase of automobile production and various changes of design, the press forming process of car body parts has become more difficult. In the case of large press molds, high hardness and abrasive resistance are needed. To overcome these problems, we attempted to develop a combined heat treatment process consisting of local laser heat treatment followed by plasma nitriding, and evaluated the characteristics of the proposed heat treatment method. From the results of the experiments, it has been shown that the maximum surface hardness is 864 Hv by the laser heat treatment, 953 Hv by the plasma nitriding, and 1,094 Hv by the combined heat treatment. It is anticipated that the suggested combined heat treatment can be used to evaluate the durability of press mold.

• 한국산학기술학회논문지
• /
• 제18권6호
• /
• pp.29-36
• /
• 2017

본 논문은 열병합 복합발전이란 하나의 프로세스에서 전기 또는 기계 동력과 열에너지의 두 형태를 생산하는 것이다. 가스터빈 열병합 발전 시스템의 각 구성부의 성능을 변수로 전체 시스템의 연료 소모와 각 구성부의 열과 전기의 성능을 표현하여야 한다. 전체시스템은 상부 시스템인 가스터빈 2대와 하부시스템인 열회수 증기발생기(HRSG) 2대, 증기터빈 1대, 지역난방열교환기 2대로 구성되어 있다. 가스터빈 열병합 복합발전시스템에서 가동시간 기준 10,000시간 후 성능시험을 각종 시험장치 설치 및 ASME PTC 46에 준한 성능시험으로 실시하였고, 발전소 전체의 종합출력과 효율에 대한 성능을 분석하였다. 이러한 성능시험 실시자료를 기초로 시험성능을 비교하여 성능변화 값을 확인하였다. 이 논문에서 가스터빈, 열회수 증기발생기, 증기터빈의 열역학적 시스템 해석을 통하여 이론적 결과 값을 산출하였다. 비교 대상은 전체 시스템의 생산열량과 대기로 배출되는 열량을 이론값과 실험값을 비교하였고, 전기출력 및 열 출력에 대한 효율을 이론값과 실제 값을 비교하였다. 가스터빈 열병합 복합발전소 성능 특성에 대한 시험결과를 열역학적 효율 특성과 비교하였으며, 0.3%의 오차를 보였다.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2006년도 하계학술발표대회 논문집
• /
• pp.89-94
• /
• 2006

For a development of the software which estimates the economics of a combined heat and power generation system in apartment estates, the thermal consumption and electric power consumption data were investigated in about 115 apartment estates. And the algorithm was developed, then the software was made by the macro function of the Excel spread sheets.

• 한국유체기계학회 논문집
• /
• 제19권6호
• /
• pp.26-33
• /
• 2016

Combined heat and power (CHP) system is one of the power generation system which can generate both electricity and heat. Generally, mid-size and big-size CHP plant in Korea generate electricity from gas turbine and steam turbine, then supply heat from exhaust gas. Actually, CHP can supply heat using district heater which is located at low pressure turbine exit or inlet. When the district heater locates after low pressure turbine, which called back pressure type turbine, there need neither condenser nor mode change operating control logic. When the district heater locates in front of low pressure turbine or uses low pressure turbine extraction steam flow, which calls condensing type turbine, which kind of turbine requires condenser. In this case, mode change operation methods are used for generating maximum electricity or maximum heat according to demanding the seasonal electricity and heat.

• 플랜트 저널
• /
• 제16권4호
• /
• pp.26-32
• /
• 2020

화력발전소에서 장치 이상이나 열화로 인해 발전효율이 저하될 때 운전자가 이를 감지하고 적시에 조처를 취할 수 있도록 지원하는 성능관리시스템은 무엇보다도 발전효율을 정확하게 예측하는 것이 중요하다. 공정용 증기 또는 난방용열(이하 공정용 증기로 단일화 표기)과 전기를 동시에 생산하는 열병합발전에 대해 지금까지 다수의 발전효율 모델들이 제안되었는데, 대부분 공정용 증기의 가치를 제대로 평가하지 못해 발전효율을 정확하게 예측하지 못했다. 본 연구에서는 발전효율 예측 모델의 계수를 조업 데이터를 통해 결정하고, 공정용 증기의 전기 환산효율(ECE, Electricity Conversion Efficiency) 모델을 적용함으로써 공정용 증기의 가치를 정확하게 평가할 수 있도록 하였다. 본 방법을 열병합발전의 설계 데이터에 적용하여 발전부하에 대한 발전효율의 추세선을 구한 결과 R2가 99.91%로 회귀 수준이 매우 높았다. 본 결과로부터 조업 데이터를 이용한 ECE 모델 계수 결정 방법이 발전효율을 정확하게 예측하여 열병합발전에 대한 성능 모니터링에 적합함을 확인할 수 있었다.

• 한국유체기계학회 논문집
• /
• 제19권6호
• /
• pp.19-25
• /
• 2016

Anti-icing is important in gas turbines because ice formation on compressor inlet components, especially inlet guide vane, can cause performance degradation and mechanical damages. In general, the compressor bleeding anti-icing system that supplies hot air extracted from the compressor discharge to the engine intake has been used. However, this scheme causes considerable performance drop of gas turbines. A new method is proposed in this study for the anti-icing in combined cycle power plants(CCPP). It is a heat exchange heating method, which utilizes heat sources from the heat recovery steam generator(HRSG). We selected several options for the heat sources such as steam, hot water and exhaust gas. Performance reductions of the CCPP by the various options as well as the usual compressor bleeding method were comparatively analyzed. The results show that the heat exchange heating system would cause a lower performance decrease than the compressor bleeding anti-icing system. Especially, the option of using low pressure hot water is expected to provide the lowest performance reduction.

• 한국수소및신에너지학회논문집
• /
• 제24권6호
• /
• pp.510-517
• /
• 2013

The ammonia-water based power generation cycle utilizing liquefied natural gas (LNG) as its heat sink has attracted much attention, since the ammonia-water cycle has many thermodynamic advantages in conversion of low-grade heat source in the form of sensible energy and LNG has a great cold energy. In this paper, we carry out thermodynamic performance analysis of a combined power generation cycle which is consisted of an ammonia-water regenerative Rankine cycle and LNG power generation cycle. LNG is able to condense the ammonia-water mixture at a very low condensing temperature in a heat exchanger, which leads to an increased power output. Based on the thermodynamic models, the effects of the key parameters such as source temperature, ammonia concentration and turbine inlet pressure on the characteristics of system are throughly investigated. The results show that the thermodynamic performance of the ammonia-water power generation cycle can be improved by the LNG cold energy and there exist an optimum ammonia concentration to reach the maximum system net work production.

• KEPCO Journal on Electric Power and Energy
• /
• 제5권2호
• /
• pp.103-111
• /
• 2019

The combined cycle plant is an integration of gas turbine and steam turbine, combining the advantages of both cycles. It recovers the heat energy from gas turbine exhaust to use it to generate steam. The heat recovery steam generator plays a crucial role in combined cycle plants, providing the link between the gas turbine and the steam turbine. Simulation of the performance of the HRSG is required to study its effect on the entire cycle and system. Computational fluid dynamics has potential to become a useful to validate the performance of the HRSG. In this study a solver has been implemented in the open source code, OpenFOAM, for combustion simulation in the heat recovery steam generator. The solver is based on the steady laminar flamelet model to simulate detailed chemical reaction mechanism. Thereafter, the solver is used for simulation of HRSG system. Three cases with varying fuel injections and gas turbine exhaust gas flow rates were simulated and the results were compared with measurements at the system outlet. Predicted temperature and emissions and those from measurements showed the same trend and in quantitative agreement.

• 전기학회논문지
• /
• 제68권4호
• /
• pp.513-522
• /
• 2019

We calculate the benefit of distributed combined heat power generators from avoiding a transmission expansion cost by building distributed generators near electricity demand centers. We determine a transmission expansion plan by solving a mixed integer linear problem, where we modify capacities of existing transmission lines and build new transmission lines. We calculate the benefit by comparing the sum of generation and transmission expansion costs with or without distributed generators through two simulation frames. In the first frame, for the current demand, we substitute existing distributed generators for non-distributed generators and measure an additional cost to balance the generation and demand. In the second frame, for increased future demand, we compare the cost to invest only in distributed generators to the cost to invest only in non-distributed generators. As a result, we show that the distributed generators have at least 5.8 won/kWh of the benefit from avoiding the transmission expansion cost.