• 에너지공학
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• 제5권2호
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• pp.183-192
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• 1996

지역난방과 발전겸용의 열병합발전(CHP)시스템과 보조열원설비의 최적운전패턴을 결정하기 위한 수리적 모델을 구축하였다. 현실상황에 접근하여 사회전체, 전력회사 및 난방사업자 각각의 관점에서 최적화 모델이 구성되었다. CHP 시설과 보조열원의 운영권이 다른 경우, 최적운전패턴은 각 당사자의 목적함수에 따라 다르며, 여기에는 열거래요금이 결정적인 영향을 미친다. 본 논문에서는 사회전체 차원의 최적운전패턴을 도출하고, 이러한 패턴이 자율적으로 이루어지게 하는 열요금 구조를 제시하였다. 분석 결과, 사회적 관점에서의 최적화패턴에서는 보조열원의 활용이 중요하게 나타났으며, 현행의 균일 열요금 구조를 시간대별로 차등화된 열요금 구조로 변환할 경우, 자발적으로 시스템전체 차원의 최적화가 이루어질 수 있음이 발견되었다.

• 설비공학논문집
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• 제28권3호
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• pp.103-109
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• 2016

The purpose of this study is to perform comparative economic evaluation for the systems of ground source heat pump (GSHP) and district heating and cooling (DHC) by focusing on the analysis of operation case of GSHP. The adapted research object is a public office building located in Seoul. The capacity of ground source pump is about 3,900 kW. Ground heat exchanger is closed loop type. The analysis period for life cycle cost is 30 years. Economic evaluation is assessed from the viewpoints of the following four parts: initial cost, energy cost, maintenance and replacement cost, and environment cost. The total life cycle cost of GSHP is approximately 8,447 million won. The cost of the DHC System is approximately 3,793 million won. The cost of the DHC is approximately 46% lower than GSHP system under the condition of current rate for GSHP and DHC.

• 신재생에너지
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• 제5권3호
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• pp.40-48
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• 2009

Recovered heat has been considered as a renewable energy in Europe since 2008 because its great effect on energy saving and carbon decreasing in plant process. Energy saving and decreasing green gas are critical issue today, so various technologies to save energy and decrease carbon dioxide in plant process have been applied to many industrial area. In this paper, the feasibility of condenser heat recovery by heat pump in power plant for district heating and fuel line preheating were reviewed by verifying energy (heat) balance and mass balance of power plant model. Some ways to compose proper system to recover heat of condenser are suggested and their possibilities are also reviewed. Limitations on heat recovery in power plant are also reviewed. The results are verified by calculating input/output energy based on actual performance test data of Taean Thermal Power Plant in Korea. There is noticeable improvement of plant performance in some cases which demand low temperature (<100 C) heat like distrcit heating, fuel line heating, and so forth.

• 한국지열·수열에너지학회논문집
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• 제7권2호
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• pp.23-29
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• 2011

The objectives of this paper are to study the characteristics of heat transfer and pressure drop of the plate heat exchanger with corrugation height by numerical analysis. Plate heat exchanger of three types was designed, which was corrugation height 3.1mm, 2.8mm and 2.5mm. The plate heat exchanger was numerically investigated for Reynolds number in a range of 950~3,380. The temperatures of the hot side were performed at $14.5^{\circ}C$ while that of the cold side was conducted at $4.5^{\circ}C$. The results show that the performance of heat transfer coefficient for corrugation height 2.5mm increases about 9.5~17.1% compared to that of corrugation height 3.1mm. On the other hand, the performance of pressure drop for corrugation height 2.5mm is remarkably higher than that of corrugation height 3.1mm, about 65.7~86.0%.

• 플랜트 저널
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• 제17권2호
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• pp.42-47
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• 2021

지역난방의 운영적 측면에서 특정시간의 피크부하 완화를 통한 효율적인 열생산과 공급 및 지역난방 공급 중단 시 급탕 공급은 난방 대비 대체가 어려워 사용자 측면의 불편함과 공급자 측면의 애로사항을 해결할 수 있는 적용 기술이 요구되고 있다. 본 연구에서는 이러한 문제점을 해결할 수 있는 기술 중 열저장 능력과 급탕공급에 적합한 78℃급 수화물계 잠열축열조를 제작하여 지역난방 사용자 아파트 급탕공급설비에 현장 적용하였다. 본 시스템의 적용 결과 기존 공급방식 대비 급탕온도의 변화가 거의 없이 일정하게 사용자에게 공급됨을 확인하였으며, 피크 열부하는 평균 35% 감소와 비상열원으로서의 활용 가능성을 확인하였다. 또한 부하균등화에 따른 피크부하 감소로 기존 열 공급시설에서 10%의 열공급 여유와 신규 열공급시설 건설비용 및 열사용자의 공사비부담금이 각 5%와 10%가 감소됨을 확인하였다.

• 한국기계기술학회지
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• 제13권2호
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• pp.63-70
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• 2011

In the present study, we developed optimal heat supply algorithm which minimizes the heat loss through the distribution pipe line in group energy apartment. Heating load variation of group energy apartment building in accordance with outdoor air temperature was predicted by the correlation obtained from calorimeter measurements of whole households of apartment building. Supply water temperature and mass flow rate were conjugately controlled to minimize the heat loss rate through distribution pipe line. Group heating apartment located in Hwaseong city, Korea, which has 1,473 households divided in 4 regions, was selected as the object apartment for verifying the present heat supply control algorithm. Compared to the original heat supply system, 10.4% heat loss rate reduction can be accomplished by employing the present control algorithm.

• 에너지공학
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• 제27권2호
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• pp.26-31
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• 2018

이 논문은 강화학습기반으로 지역난방 열사용자 기계실 설비의 열효율 향상을 시도하는 연구를 소개하며, 한 예시로서 모델을 특정하지 않는 강화학습 알고리즘인 딥큐러닝(deep Q learning)을 활용하는 학습 네트워크(DQN)를 구성하는 일반적인 방법을 제시한다. 또한 복수의 열에너지 기계실에 설치된 IoT 센서로부터 유입되는 방대한양의 데이터 처리에 있어 에너지 분야에 특화된 빅데이터 플랫폼 시스템과 열수요 통합관리시스템에 대하여 소개 한다.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 춘계학술발표대회 논문집
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• pp.179-184
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• 2011

The development of new energy has attracted consideration attention due to the high oil price and environmental problems. In advanced country, they have tried to carry out a long range plan for energy. We need to develop new energy for Low Carbon Green Growth in Korea. The building is 30% among ratio of energy consumption in Korea. And in the past, heating energy was high ratio for energy using at home. But recently, the demand for cooling energy keeps growing due to rising average temperature on the earth and improvement of life quality. In this situation, the energy of lake water and ocean water has studied to utilize in advanced country because of low temperature at underwater. But the study for deep water is still a lot left to do. In this study, we analyzed district cooling system and the present condition. Analyzing the deep lake water cooling system in Toronto, we found an application of district cooling system using deep ocean water. Deep lake water uses heat source for district cooling and water source for city in Toronto. So reducing the initial cost, this city had economic effect. When DLWC was applied at existing building, the heat exchanger was installed instead of cooling tower and refrigerator. And the heat exchanger used to connect main pipe with cool water on city. System using deep ocean water can be applied as a similar way to supply cool water from lake to building.

• Corrosion Science and Technology
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• 제19권4호
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• pp.189-195
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• 2020

Two air vents situated on a heat transport pipe in district heating system were exposed to the same environment for 10 years. However, one air vent was more corroded than the other. It also had a hole on the top of the front-end pipe. Comparative analysis was performed for these air vents to identify the cause of corrosion and establish countermeasures. Through experimental observation of the damaged part and analyses of powders sampled from air vents, it was found that corrosion was initiated at the top of the front-end pipe. It then spread to the bottom. Energy dispersive X-ray spectroscopy results showed that potassium and chlorine were measured from the corroded product in the damaged air vent derived from rainwater and insulation, respectively. The temperature of the damaged air vent was maintained at 75 ~ 120 ℃ by heating water. Rainwater-soaked insulation around the front-end pipe had been hydrolyzed. Therefore, the damaged air vent was exposed to an environment in which corrosion under insulation could be facilitated. In addition, ion chromatography and inductively coupled plasma measurements indicated that the matrix of the damaged front-end pipe contained a higher manganese content which might have promoted corrosion under insulation.

• 한국재료학회지
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• 제29권1호
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• pp.11-15
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• 2019

Severe wall thinning is found on the tube of a low-pressure evaporator(LPEVA) module that is used for a heat recovery steam generator(HRSG) of a district heating system. Since wall thinning can lead to sudden failure or accidents that lead to shutdown of the operation, it is very important to investigate the main mechanism of the wall thinning. In this study, corrosion analysis associated with a typical flow-accelerated corrosion(FAC) is performed using the corroded tube connected to an upper header of the LPEVA. To investigate factors triggering the FAC, the morphology, composition, and phase of the corroded product of the tube are examined using optical microscopy, scanning electron microscopy combined with energy dispersive spectroscopy, and x-ray diffraction. The results show that the thinnest part of the tube is in the region where gas directly contacts, revealing the typical orange peel type of morphology frequently found in the FAC. The discovery of oxide scales containing phosphate indicates that phosphate corrosion is the main mechanism that weakens the stability of the protective magnetite film and the FAC accelerates the corrosion by generating the orange peel type of morphology.