• 전기의세계
• /
• 제60권11호
• /
• pp.56-63
• /
• 2011

In the face of global warming and resource depletion, a smart grid has been suggested as one way of contributing to abating the environment problems and increasing energy efficiency. Smart grids utilize renewable energy which has intermittent and irregular output power depending on weather conditions. In order to maintain stability and reliability of the power system, smart grids need to have complementary measures for the possible unstable system conditions. Cogenerating systems such as Combined Heat and Power(CHP) can be one good solution as it has capability of instantly increasing or decreasing output power. Therefore, this paper investigates the connectivity between Combined Heat and Power systems and smart grid technologies. The smart grid national roadmap formulated by South Korea Ministry of Knowledge and Economy and 'IEC Smart Grid Standardization Roadmap' are analyzed to extract related components of the smart grid for the CHP connection. Also, case studies on demonstration projects for smart grids with CHP systems completed or currently being implementing in the world are presented.

• 한국태양에너지학회:학술대회논문집
• /
• 한국태양에너지학회 2009년도 추계학술발표대회 논문집
• /
• pp.74-79
• /
• 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.

• 대한기계학회논문집B
• /
• 제41권8호
• /
• pp.545-552
• /
• 2017

본 연구에서는 1 kW급 가정용 열병합 시스템의 원동기로 설계된 스털링 엔진의 고온 열교환기에 대하여 Fin 길이, 간격, 각도 등을 조정한 새로운 형상 및 기존 형상에 대하여 수치해석을 수행하여 형상 개선에 따른 성능 향상을 확인하였다. 형상을 개선하는 과정에서 고려하지 않았던 공기예열기를 포함하여 수치해석을 수행한 결과 실린더 헤드 부분에서 음의 열유속이 발생하는 현상이 관찰되었다. 배가스 온도 및 연소실 벽면 온도를 분석하여 이 현상을 규명하였다. 다음으로 이상적인 사이클을 가정하여 형상 개선에 의한 열전달량 증가가 열역학적 사이클 및 시스템 성능에 미치는 영향을 예측하였다.

• 한국수소및신에너지학회논문집
• /
• 제17권3호
• /
• pp.293-300
• /
• 2006

KIER has been developing a Ru-based preferential oxidation catalysts and a novel fuel processing system to provide hydrogen rich gas to residential PEMFCs system. The catalytic activity of Ru-based catalysts was investigated at different Ru loading amount and different support structure. The obtained result indicated that 2 wt% loaded Ru-based catalyst supported on ${\alpha}-Al_2O_3$ showed high activity in low temperature range and suppressed the methanation reaction. The developed prototype fuel processor showed thermal efficiency of 78% as a HHV basis with methane conversion of 92%. CO concentration below 10 ppm in the produced gas is achieved with separate preferential oxidation unit under the condition of $[O_2]/[CO]=2.0$. The partial load operation have been carried out to test the performance of fuel processor from 40% to 80% load, showing stable methane conversion and CO concentration below 10 ppm. The durability test for the daily start-stop and 8 h operation procedure is under investigation and shows no deterioration of its performance after 50 start-stop cycles. In addition to the system design and development.

• 상하수도학회지
• /
• 제24권3호
• /
• pp.319-332
• /
• 2010

In general, wastewater treatment systems consume high-energy consumption depending on operation characteristics of the facilities. Therefore, greenhouse gas(GHG) reduction activities that are application of digestion gas, induction of renewable energy etc. are conducted to reduce energy consumption and to increase energy independence ratio. In this study, GHG reduction in wastewater treatment system identified, searched application of Clean Development mechanism(CDM) approved methodology. If the methodologies apply to GHG reduction activities such as application of digestion gas, heat pump system using the wastewater as heat source, hydropower using the methodology determined CDM applicability, otherwise through several assumptions calculated expectable GHG reduction emissions and determined CDM applicability. As a result, the order of calculated GHG reduction emission showed that collected and energy generation of digestion gas is 66,775 $tCO_2$/yr, gas engine cogeneration system is 8,182 $tCO_2$/yr, heat pump system using the wastewater as a heat source is 72,715 $tCO_2$/yr, and hydropower is 561 $tCO_2$/yr. Consequently, the order of calculated Certified Emission Reductions(CERs) benefit showed that heat pump system using the wastewater, as a heat source is 1,381 million won/yr was estimated as the highest, followed by a collected and energy generation of digestion gas is 1,268 million won/yr.

• 한국태양에너지학회 논문집
• /
• 제39권1호
• /
• pp.21-32
• /
• 2019

Solar hot water system produces hot water using solar energy. If it is not used effectively, overheating occurs during the summer. Therefore, a lot of research is being done to solve this. This study develops thermoelectric power module applicable to solar hot water system. A thermoelectric material can directly convert thermal energy into electrical energy without additional power generation devices. If there is a temperature difference between high and low temperature, it generate power by Seebeck effect. The thermoelectric module generates electricity using temperature differences through the heat exchange of hot and cold water. The water used for cooling is heated and stored as hot water as it passes through the module. It can prevent overheating of Solar hot water system while producing power. The thermoelectric module consists of one absorption and two radiation part. There path is designed in the form of a water jacket. As a result, a temperature of the absorption part was $134.2^{\circ}C$ and the radiation part was $48.6^{\circ}C$. The temperature difference between the absorption and radiation was $85.6^{\circ}C$. Also, The Thermoelectric module produced about 122 W of irradiation at $708W/m^2$. At this time, power generation efficiency was 2.62% and hot water conversion efficiency was 62.46%.

• 유기물자원화
• /
• 제20권4호
• /
• pp.61-74
• /
• 2012

우리나라는 1960년대에 들어서 경제개발계획의 수립과 더불어 산업발전 정책이 강력히 추진되기 시작하며 많은 산업단지가 조성되어 있다. 현재는 지속적인 발전이 가능한 산업단지로 만들기 위하여 정부에서는 산업단지에서 발생되는 부산물과 폐기물을 다른 기업의 원료나 에너지로 재활용하는 생태산업단지 구축사업을 추진하고 있다. 이와 관련하여 본 연구에서는 연구대상지역인 A 산업단지에서 발생되는 슬러지의 물리화학적 특성을 분석하였고, 슬러지의 에너지화 시설 설치에 따른 경제성 및 부대효과를 분석함으로써 사업화 가능성을 검토하였다. 연구대상지역인 A산업단지에서 발생되는 슬러지발생 업종의 비율은 92%가 석유 화학업종인 것으로 분석되었다. 이렇게 발생된 슬러지는 매립>소각>>재활용>해양투기의 순으로 처리되고 있는 것으로 조사되었으며 슬러지를 채취하여 분석한 결과 발생량 가중치 평균으로 3,891kcal/kg인 것으로 분석되었다. 분석된 기초 데이터를 바탕으로 건조시설과 열병합 발전소를 설치하여 운영 할 경우 설치비용, 운영비용, 운영이익을 산출하였고, 총 8가지 Case로 분류하여 흑자전환유무 및 그 시점에 대한 시뮬레이션을 하였다. 분석결과 건조시설과 열병합발전소를 설치 운영하며 국고지원을 받을 경우 3년에 원금회복 후 4년째부터 흑자를 나타낼 것으로 분석되어 사업화 경제성이 있는 것으로 평가되었다.

• 대한기계학회논문집B
• /
• 제33권4호
• /
• pp.255-263
• /
• 2009

The most concerning issue of these days is the energy crisis caused by increasing threat of dependence on imported oil and volatile market trend. Under these circumstances, the PHEV(plug-in hybrid electric vehicle) is drawing attention for the next generation's car which could give a chance to decrease the dependence on imported oil and reduce the environmental impact of vehicle. The fueling cost of PHEV, one of the core factor of decision about buying car, should be calculated in the circumstances of Korea to make sure that PHEV has competitive power in real market. The fuel cost saving of PHEV versus CV(conventional vehicle) is simulated and discussed in the condition of increasing gasoline cost, electricity rate, and city-gas rate. In conclusion, the PHEV60-FS shows the best economic feasibility when gasoline price goes up. The PHEV20 has the most stable economic feasibility as electricity rate increases. The fuel cell cogeneration system for RPG could be an alternative for charger of PHEV in the near future.

• 대한전기학회논문지:전력기술부문A
• /
• 제48권9호
• /
• pp.1096-1102
• /
• 1999

This paper discusses the evaluation of interconnection capacity of small cogeneration(SCOGN) systems to the power distribution systems from the viewpoint of voltage regulation. Power utilities are required to keep the customers' voltage profile over a feeder close to the rated value under all load conditions. However, it is expected that the interconnection of SCOGNs to the power distribution systems impacts on the existing voltage regulation method and customers' voltage variations. Therefore, SCOGNs should be integrated to the automated power distribution systems to prevent interconnection problems and supply high quality electricity to the customers. For these reasons, we should proceed with the evaluation of interconnection capacity of SCOGNs to the power distribution systems. However, it is generally impossible to perform actual testing on the power distribution systems, and standardized methodologies and guidelines are not developed to evaluate it. The criterion indexes for voltage regulation and variations are presented in order to evaluate the interconnection capacity of SCOGNs to the power distribution systems. In addition, the evaluation methodology of interconnection capacity of SCOGNs for power distribution systems is presented. It is expected that the resulted of this paper are useful for power system planners to determine the interconnection capacity of SCOGNs and dispersed storage and generation (DSG) systems to the power distribution systems.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2009년도 하계학술발표대회 논문집
• /
• pp.172-176
• /
• 2009

We developed a program, "CogenSim-$\mu$," to simulate the operation of micro-combined heat and power (${\mu}CHP$) system. The CogenSim-$\mu$ can reflect the variation of energy efficiency by handling the real-time loads (heat and power) fluctuation. The result obtained using this program was compared with the real operation of 30 kWe gas engine driven ${\mu}CHP$. It was found that the CogenSim-$\mu$ could predict the amount of generated-power, recovered-heat and consumed-fuel with the error less than 3%, and heat and power efficiency with the error less than 4%. The CogenSim-$\mu$ reconstructed the profile of on-off cycle, which represented the operation of a facility, with more than 93% accuracy. The CogenSim-$\mu$ can reflect the effects of various factors such as size of thermal storage tank, desired temperature of reservoir water, natural frequency of generator, etc. As a result, the CogenSim-$\mu$ can be used to optimize the ${\mu}CHP$ operation.