• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.8
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• pp.629-635
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• 2008

Recently, microturbines have received attention as a small-scale distributed power generator. Since the exhaust gas carries all of the heat release, the microturbine CHP (combined heat and power) system is relatively compact and easy to maintain. Generating hot water or steam is usual method of heat recovery from the microturbine. In this work, a heat recovery unit producing hot water was installed at the exhaust side of a 30 kW class microturbine and its performance characteristics following microturbine power variation was investigated. Heat recovery performance has been compared for different operating conditions such as constant hot water temperature and constant water flow rate. In particular, the influence of water flow rate and hot water temperature on the recovered heat was analyzed.

• The KSFM Journal of Fluid Machinery
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• v.12 no.2
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• pp.46-51
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• 2009

Recently, microturbines have received attention as a small-scale distributed power generator. Since the exhaust gas carries all of the heat release, generating hot water is usual method of heat recovery from microturbine CHP (combined heat and power) systems. The power of microturbines decreases as ambient temperature increases. This study predicted micoturbine power boost by injecting hot water generated by heat recovery. Influence of injecting water at two different locations was examined. Water injection improves power, but efficiency depends much on the injection location. Injecting water at the compressor discharge shows a much higher efficiency than the combustor injection. However, the combustor injection may have as much available cogeneration heat as the dry operation, while the available heat in the compressor discharge injection is much smaller than the dry operation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.11
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• pp.1610-1616
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• 2013

Recently, district heating and cooling (DHC) systems based on combined cycle generation (CCG) providers are increasing in Korea. Since characteristics of combined heat and power (CHP) generators and heat demands of providers, heat trading between DHC providers based on the economic viewpoint is required; the heat trading has been doing. In this paper, a mathematical model for optimal operation based on heat trading between DHC providers is proposed. Especially, start-up characteristic of CCG is included. The operation model is established by mixed integer linear programming (MILP).

• Plant Journal
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• v.16 no.4
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• pp.26-32
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• 2020

The performance monitoring system in the power plant should have the capability to estimate power generation efficiency accurately. Several power generation efficiency models have been proposed for the combined heat and power (CHP) plant which produces both electricity and process steam(or heating energy, hereinafter expressed by process steam only). However, most of the models are not sufficiently accurate due to the wrong evaluation of the process steam value. The study suggests Electricity Conversion Efficiency (ECE) model with determination of the heat rate of process steam using operational data. The suggested method is applied to the design data and the resulted trajectory curve of power generation efficiency meets the data closely with R2 99.91%. This result confirms that ECE model with determination of the model coefficient using the operational data estimate the efficiency so accurately that can be used for performance monitoring of CHP plant.

• Journal of Energy Engineering
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• v.24 no.3
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• pp.67-73
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• 2015

Almost base-loaded power plants such as flaming coal and nuclear energy require large-scale transmission facilities (LTFs) in order to send electricity to remote consumption areas. As well known, LTFs incur various social costs. However, a decentralized generation source such as integrated energy business (IEB)-based combined heat and power (CHP) plant is located in nearby electricity-consuming area, and thus it does not demand LTFs, providing the benefits from avoiding the damages caused by them. This study attempts to measure the benefits of avoiding the damages from the LTFs by the use of the contingent valuation (CV) method. To this end, a national survey of randomly chosen 1,000 households was implemented and the public's willingness to pay (WTP) for substituting consumption of electricity generated from flaming coal-fired power plant, currently a dominant generation source in Korea, with that produced from IEB-based CHP plant. The results show that the WTP for the substitution is estimated to be about 41.4 won per kWh. Considering that this value amounts to 33% of the average price of residential electricity in 2014, the external benefit of the IEB-based CHP as a decentralized generation appears to be large.

• Plant Journal
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• v.14 no.3
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• pp.42-48
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• 2018

If the combined operation of Gwanggyo Cogeneration plant is similar to that of 2017, the CHP return temperature is lowered to $4^{\circ}C$, $6.3^{\circ}C$ and $7.8^{\circ}C$ according to the increase of heat surface area and the electric power is increased by 413 kW and 676 kW from its original 39,025 kW, and when the heat surface area is increased 75% electric power increases by 834 kW, totaling 39,859 kW. NPV, which is an economic analysis standard, is worth 350 million won, 500 million won, and 520 million won, and all measures to increase the heat surface area are proven to be worth the investment. As the heat transfer area increased, the electric power and NPV increased proportionally but the rise amount decreased. The electrical output and NPV were found to be the highest among the three options when the heat transfer area was increased by 75%.

• Advances in Energy Research
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• v.4 no.1
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• pp.29-45
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• 2016

There has been a growing interest in the recent time for the development of solar power tower plants, which are mainly used for utility scale power generation. Combined heat and power (CHP) is an efficient and clean approach to generate electric power and useful thermal energy from a single heat source. The waste heat from the topping Brayton cycle is utilized in the bottoming HRSG cycle for driving steam turbine and also to produce process steam so that efficiency of the cycle is increased. A thermal storage system is likely to add greater reliability to such plants, providing power even during non-peak sunshine hours. This paper presents a conceptual configuration of a solar power tower combined heat and power plant with a topping air Brayton cycle. A simple downstream Rankine cycle with a heat recovery steam generator (HRSG) and a process heater have been considered for integration with the solar Brayton cycle. The conventional GT combustion chamber is replaced with a solar receiver. The combined cycle has been analyzed using energy as well as exergy methods for a range of pressure ratio across the GT block. From the thermodynamic analysis, it is found that such an integrated system would give a maximum total power (2.37 MW) at a much lower pressure ratio (5) with an overall efficiency exceeding 27%. The solar receiver and heliostats are the main components responsible for exergy destruction. However, exergetic performance of the components is found to improve at higher pressure ratio of the GT block.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.347-348
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• 2006

발전기의 기동정지계획(unit commitment)에 있어서 전통적인 방식은 발전기를 기동/정지하는데 드는 비용(cost)을 기반으로 결정해 왔다. 그러나 전력시장의 변화에 따라 반전기의 기동정지계획에 전력 요금(price)의 중요성이 인식되면서 요금에 기반한 기동정지계획에 대한 연구들이 진행되고 있다. (1) 본 논문에서는 이러한 요금 기반 기동정지계획을 한국의 전력시장 환경에서 소형열병합발전기(micro-CHP(combined heat and power))에 적용해 본다. 한국의 전력시장에서 주택에 사용되는 전력 요금에 대해서는 누진제가 적용된다. 그러므로 븐 논문에서는 아파트에 설치된 소형열병합발전기의 요금 기반 기동정지계획의 시뮬레이션 결과를 분석함으로써 전력 요금의 누진제가 기동정지계획에 어떠한 영향을 주는지에 대해서 논하고자 한다.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.539-540
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• 2006

소형 열병합 (CHP, Combined Heat & Power)은 발전 용량이 1MW 이하인 발전 시스템을 지칭하는 용어로, 전기와 더불어 원동기에서 발생한 폐열을 회수하여 사용한 수 있는 발전 시스템을 말한다. 대표적인 원동기로서는 가스 엔진, 터빈, 마이크로 터빈, 연료 전지 등이 있다. 소형 열병합 시스템은 폐열 회수의 특징으로 기존 시스템에 비해 50% 이상의 에너지 이용 효율이 높으며, 기존의 대형 발전 시스템에서 필연적으로 존재하는 송전 및 배전 손실이 존재하지 않는 수요지 발전의 특징도 갖고 있어서 연료 절약형 에너지 생산 시스템으로서의 높은 가치를 가지고 있다. 또 다른 장점으로 열병합 발전 시스템은 여름철의 최대 전력 부하를 제거하는 역할을 할 수 있음으로 국가 전력 수요 공급의 안정화에 기여하는 바가 크다. 본 논문에서는 최근에 개발된 325kW급 열병합 가스엔진 발전 시스템의 주제어를 담당하는 통합 제어 장치의 개발과 소형 열병합 시스템의 시험 결과에 대해서 소개한다.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.74-79
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• 2009

The generation of electric power and plant facilities have been attempting to improve energy efficiency with many efforts as those being basis of our country's economy. In particular, the CHP(Combined Heat Power plant) system, is producing the electricity and process steam, has generally been using for the cogeneration plants. When CHP system operates, the steam has to maintain the high temperature and high pressure in order to have high efficiency of electric power production as much as possible. In addition, the exhausted steam from the turbine has to reform proper temperature to use the needed process. The major purpose of desuperheater is that the superheated steam changes into the saturated steam because it is more efficient and suitable for using the process, furthermore, it is more convenient and stable regarding the process temperature control. The design of the desuperheater obtained through the experiment and preceding analysis. This paper is verified by analysis that water spray nozzle(${\Phi}$=28mm) shows the best ability under the real power plant condition.