고공환경모사 시험설비 냉각수 공급시스템 설계

김중일(Joongil Kim),고민호(Minho-Ko),김이중(Leejung Kim),서중규(Jungyu Seo),김형육(Hyungyuk Kim),김유(Yoo Kim),고영성(Youngsung Ko) 한국추진공학회 2013 한국추진공학회 학술대회논문집 Vol.2013 No.12

본 논문에서는 예비설계를 통한 고공환경모사 시험설비의 각 파트별 냉각수 공급시스템의 요구유량을 제시하였으며 요구유량에 따라 펌프식 및 가압식으로 나누어 냉각수 공급시스템을 설계ㆍ제작하였다. 펌프식 냉각수 공급시스템 및 가압식 냉각수 공급시스템의 cavitation venturi 검증실험을 통해 안정한 냉각수 유량을 공급할 수 있음을 확인하였다. In this paper, mass flow rate of a cooling water supply system was presented through preliminary design of high-altitude test facility(HATF). The cooling water supply system consisted of pressurization and pump type to satisfy flow rate requirements. Hydraulic tests were performed to verify mass flow rate of cooling water. The experimental result showed that the cooling water supply system could supply accurate mass flow rate to each part by cavitation venturies.

저온냉각수 및 Free Cooling 적용에 의한 데이터센터의 냉방성능 검토

김유진(Kim, Yu-Jin),하주완(Ha, Ju-Wan),박경순(Park, Kyung-Soon),이건호(Lee, Keon-Ho),송영학(Song, Young-Hak) 한국건축친환경설비학회 2020 한국건축친환경설비학회 논문집 Vol.14 No.5

The size and number of internet data center (IDC) has been growing rapidly as IT demand has increased recently. IDC needs 10 times as much energy as regular office buildings, there are problems with global warming and increasing carbon emissions. IDC"s cooling energy consumption to maintain the IT equipment environment accounts for about 35% of total energy consumption. Therefore, the use of cooling energy was reviewed through simulation by applying the low cooling water temperature system and the free cooling system in this system. Based on this, cooling performance was analyzed using MLC (Mechanical Load Component) indicators. As a result of the simulation, energy consumption in low cooling water temperatures decreased by 8% compared to normal water-cooling systems, while WSE (Water Side Economizer) and ASE (Air Side Economizer) decreased by 26% and 32%, respectively. Since the MLC of conventional water-cooled system was 0.13 which is lower than Incheon"s maximum allowable value of 0.18. As a result of the MLC analysis, it was determined that the cooling system was properly designed. The cooling energy usage showed a significant reduction rate in the order of low cooling water temperature, WSE, and ASE, and the ASE was the most efficient operation with 26.3%.

Water-side economizer 시스템의 냉방 성능 향상을 위한 Free cooling 운전 기간 확대 알고리즘 개발

김광희,김유진,송영학 한국건축친환경설비학회 2023 한국건축친환경설비학회 논문집 Vol.17 No.5

As demand for data centers is increasing, the importance of reducing cooling energy is emphasized. In this paper, a free cooling operation period extension algorithm has been developed based on the flow rate control in the WSE (Water-side economizer) system to improve the cooling performance of data centers. In order to increase the supply and return temperature of chilled water and reduce the cooling tower approach temperature that determines the free cooling period, CRAH (Computer room air handler) airflow, chilled water flow rate, cooling tower flow control sequence was presented. As a result, the energy consumption of the chiller decreased by 28% per year, and the free cooling operation increased by 1,324 hours. Since the developed algorithm control the operating variables of loops that make up a general cooling system and heat exchange between multiple loops, it is expected to have high scalability that can be applied to buildings and cooling systems with different conditions

Water-side economizer의 Free cooling 운전 기간 확대를 위한 냉각탑 Fan 풍량 제어에 관한 연구

김유진,송영학,김환용 한국건축친환경설비학회 2023 한국건축친환경설비학회 논문집 Vol.17 No.3

Recently, various strategies have been proposed to reduce energy of Water-side economizer (WSE), and in particular, due to the increase in the construction of data centers, many studies have been conducted to reduce cooling energy. Therefore, in this study, a strategy to expand full-free cooling according to the decrease in the cooling tower outlet temperature of the cooling tower was established by increasing the cooling tower air volume for the WSE system. In addition simulation calculations were performed to analyze the effectiveness of the strategy to analyze the energy savings. According to the simulation calculation of the cooling tower fan air volume at intervals of 5% in the range of 50% ~ 100%, the energy was saved from 100% to 22.4% compared to the cooling tower fan ratio of 50%, during the representative week of partial load, a total of 100 hours of full-free cooling operation time was increased. Therefore, in order to implement the efficient operation of the WSE system, it is necessary to first consider increasing the cooling tower fan air volume as much as possible.

알루미늄 전기응집을 이용한 냉각탑 배출수 구리 제거

김진수,신총수,이상일 대한환경공학회 2018 대한환경공학회지 Vol.40 No.1

본 연구에서는 전기응집을 이용하여 냉각수의 구리를 제거하고자 하였다. 전기응집 실험에 앞서 냉각탑 가동에 따른냉각수의 구리 농도, 경도, pH, 전기전도도를 모니터링 하였다. 냉각탑이 가동될수록 구리 및 경도 물질이 농축되는 현상을확인할 수 있었으며 전기전도도와 높은 상관관계를 나타냈다. 전기응집은 전극 17쌍, 전극간격 0.3 cm, 전류밀도 0.0167 A/cm2으로 진행하였으며, 냉각수가 일정수준의 전기전도도를 나타내기 때문에 별도의 전해질은 추가하지 않았다. 실험결과HRT (hydraulic retention time)가 증가할수록 구리 제거율이 증가하였다. pH는 별도의 약품주입 없이도 pH 8 부근으로 조정되는 것을 확인할 수 있었다. 전기전도도의 경우 처리 후 감소함을 확인할 수 있었으나 그 수준은 미미하였다. 생태독성을 확인해 본 결과, 냉각수는 처리 없이 배출하기에는 다소 높은 독성값을 나타냈으며, 전기응집 처리 후에는 독성이 크게 감소하는 것을 확인할 수 있었다. This study was conducted to treatment of copper in cooling water by using electrocoagulation. Before the electrocoagulation experiment, monitored concentration of copper, hardness, pH and conductivity in cooling water for operating cooling tower. As the cooling tower was operated, it was confirmed that copper and hardness were concentrated, and it showed a high correlation with conductivity. Electrocoagulation operation condition was 17 pairs of electrodes, 0.3 cm of electrode gap and 0.0167 A/cm2 of current density. Electrolyte need not add because the cooling water has conductivity. Electrocoagulation experiment results were showed that the copper removal efficiency increased with increasing hydraulic retention time (HRT). It was confirmed that pH was adjusted to about 8 without additional chemical injection. Conductivity decreased after electrocoagulation treatment but, the decreasing trend was insignificant. Checking the toxicity, the cooling water showed high toxicity and the toxicity decreased after the electrocoagulation treatment.

선박메인엔진 냉각수를 활용한 선박폐열발전-담수화 시스템 성능평가 시뮬레이션

임승택,김현주,문정현,이호생 한국마린엔지니어링학회 2019 한국마린엔지니어링학회지 Vol.43 No.9

The demand for high efficiency vessels is increasing due to the problems of international marine environments and rising ship oil prices. As a result, research on power generation methods that utilize waste heat from ships has begun. In this study, organic Rankine cycle (ORC)-based waste heat power is designed using engine cooling water of a 58MW ship and is compared through simulation with the desalination capacity of a desalination plant that uses cooling water of 80 °C passed through a waste heat power. The power output and heat transfer performance are assessed by applying various refrigerants to select the working fluid for ship waste heat recovery, and then the performances of new refrigerants are compared to identify one with a low global warming potential. The study also compared the output of a ship waste heat recovery system with generated waste heat discharged to the sea by applying various types of engine types and cooling water flow rates. The power output and thermal power are compared when engine coolant is supplied at temperatures of 80 °C, 85 °C, and 90 °C. Finally, the optimal operating conditions of the ship waste heat–desalination system are determined by comparing the evaporation temperature and fresh water production rate based on the evaporation pressure of the ship desalination plant. The waste heat recovery–desalination system using a 90 °C heat source from the 10S90ME 58MW ship confirmed a pure water output of 564.4 kW and fresh water production of 1.278 kg/s when the R245fa working fluid was applied, and a reduction of 35%. 국제적 해양 환경문제와 선박유의 가격상승으로 고효율 선박의 수요가 증가하고 있으며, 선박에서 발생하는 폐열을 활용한 발전 방식의 연구가 진행되고 있다. 본 연구에서는 58MW급 선박의 엔진 냉각수를 활용하여 ORC를 기반으로한 폐열발전을 시뮬레이션을 통해 설계하였으며, 폐열발전을 통과한 80℃의 냉각수를 활용한 담수화 설비의 담수생산량을 비교하였다. 선박폐열발전의 작동유체의 선정을 위한 다양한 냉매를 적용하여 발전출력과 열전달 성능을 비교하였으며, 저 GWP 냉매를 적용하기 위하여 신냉매의 성능을 비교하였다. 다양한 선종의 엔진타입과 냉각수 유량을 적용하여선박폐열발전의 출력과 바다로 배출되는 폐열 발생을 비교하였으며, 엔진 냉각수 온도가 80℃, 85℃, 90℃로 공급될 때발전 출력과 페열량을 비교하였다. 또한, 선박 담수화 설비의 증발압력의 변화에 따른 담수 생산량과 증발 온도를 비교하여 선박폐열발전-담수화 시스템의 최적 운전조건을 도출하였다. 10S90ME의 58MW급 선박의 90℃ 열원을 활용한 폐열발전-담수화 시스템은 R245fa 작동유체를 적용하여 564.4kW의 순수 발전출력과 1.278kg/s의 담수생산량을 확인하였으며, 기존 폐열 발생량 대비 35%의 감소량을 확인하였다.

LCC를 고려한 KSTAR 냉각수설비의 설계특징 및 성능평가

김영진(Young-Jin Kim),정남용(Nam-Yong Jung),임동석(Dong-Seok Im),김상태(Sang-Tae Kim),김양수(Yaung-Su Kim),유성연(Seong-Yeon Yoo) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11

KSTAR is the final aim that is development of the nuclear fusion power plant to generate the green and stable high-capacity electricity. Most of the components of KSTAR are to obtain the thermal stability by deionized (DI) water. KSTAR performed the plasma experiment annual is used the electric energy of many billions won per year, and the cooling water system (CWS) currently comprise about twenty five percent of the total energy. Therefore, the CWS should be minimized fabrication, operation and maintenance costs. In order to minimize the life cycle cost (LCC), the CWS has design features as following: to classify as a pulse load cooling loop type operated intermittently and a continuous load cooling loop type operated continuously, to apply two-step heat exchanger (HE) in the cooling loops, to install the by-pass pipe between the cooling tower water loops and the chilled water loops for shutdown chillers in winter, to equip a separate small pump system and interface piping because the first neutral beam injection (NBI-1) is carried out the experiment operation at day and the standby unload one, being operation for beamline vacuum, at night, and to fit a 3-way valve and a pre-cooler in a plasma facing component (PFC) nitrogen gas baking system. In operation results, we analyzed the flow stream in a cooling water storage tank and a tower water header, the water temperature state in the two-step HE, and the performance of a polishing system, the NBI-1 cooling system and the PFC nitrogen gas baking system.

물 분사가 포함된 로켓 연소 후류 유동특성 연구

강선일,남중원,황도근 한국항공우주학회 2012 한국항공우주학회 학술발표회 논문집 Vol.2012 No.11

본 논문에서는 자유류 형태의 로켓 연소 후류의 유동 특성과 후류 중심부에 직접 분사되는 냉각수에 의한 영향을 전산유체해석을 통해 알아보았다. 먼저 화염유도로의 구조 및 사용되는 냉각수 분사 시스템은 KSLV-1 발사대에 적용된 시스템을 사용하였다. 유동 해석을 통하여 연소 후류 중심부에 직접 분사된 냉각수는 연소 후류와의 혼합 및 증발 과정을 거쳐 후류의 전 온도를 절반 이하로 낮추는 효과가 있음을 확인하였다. 하지만 해석 결과를 통해 냉각수 분사 효과가 온도에 영향을 주는 영역이 반경방향으로 한정됨을 또한 확인할 수 있었는데, 이는 후류와 냉각수간의 운동에너지 차이로 인한 침투 깊이의 제한에 기인함을 알 수 있었다. In this paper, the flow characteristics of rocket exhaust plume as a free-stream and the influence of direct core injection of cooling water is investigated through computational fluid analysis. First of all, configurations of the KSLV-1 flame deflector and cooling water spray system are introduced. As a result of analysis, direct core injection of cooling water can reduce total temperature of plume under half because of mixing and evaporation of water and plume. Also the analysis can show the cooling effect has limits in radial direction. It is because penetration depth limit of water due to the kinetic energy difference between sprayed water and plume.

2.0 Turbo-GDI 차량의 수랭식 인터쿨러 적용 및 평가

이용규(Yongkyu Lee),박진일(Jinil Park),이종화(Jonghwa Lee),박경석(Kyoungseok Park),김광연(Kwangyeon Kim),이준호(Junho Lee) 한국자동차공학회 2012 한국자동차공학회 부문종합 학술대회 Vol.2012 No.5

There are two types of cooler for cooling charged air. Air cooled air cooler and water cooled air cooler are those. Air cooled air cooler has simple installation and low price. So it is widely used. But it has low cooling efficiency at repeated rapid acceleration driving. Because it is cooled by air which has lower Specific-Heat than water. And cause of long path, it doesnt have good turbo lag. Water cooled air cooler has complicated installation and high price. However it has high cooling efficiency at repeated rapid acceleration driving. Because it is cooled by water which has higher Specific-Heat than air. Also, it has good turbo lag. Because it has shorter path than air cooled air cooler. In this study, confirm the cooling efficiency and improvement of turbo lag on the turbo system which Intercooler system is changed air cooled air cooler to water cooled air cooler.

열교환 시스템에서 냉각수의 파울링특성과 물리적 수처리 방안

성순경(Sung-Kyung Sung),서상호(Sang-Ho Suh),노형운(Hyung-Woon Roh) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.5

The objective of this study was to investigate the efficiency of physical water treatment method in preventing and controlling fouling accumulation on heat transfer surface in a laboratory heat exchanging system with artificial water. For the purpose of the mitigation of fouling in a heat exchanging system, physical water treatments such as the method using graphite and metal electrodes were proposed. The tests were limited to cooling-tower water applications, where water was repeatedly treated by the physical water treatment devices. The results of fouling resistances obtained were used to analyze the effect of the physical water treatment. Futhermore, the values of pH and surface tension of water samples were measured in order to evaluate the fouling mitigation effects.