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최재호(Jae Ho Choi),임효재(Hyo Jae Lim),김창업(Chang Eob Kim),권정태(Jung Tae Kwon) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5
This study aims at analyzing the flow characteristics of the electromagnetic pump using a linear induction motor (LIM) for transferring molten metals. The flow characteristics of the pump are simulated by magnetohydrodynamic(MHD) program. In this system, the LIM is used for transferring molten metal by electromagnetic force. The molten metal is treated as the secondary part of the LIM. Since the LIM produces an electromagnetic force in the duct, the molten metal can flow from the furnace to the reservoir. The flow characteristics of the pump are analyzed using MHD program for magnetic field of 0.1[T] in duct. In order to prove the analysis, we made a prototype electromagnetic pump using LIM.
선형유도전동기를 이용한 전자기 펌프의 특성해석 및 실험
김창업,전문호,권정태,임효재,Kim, Chang-Eob,Jeon, Mun-Ho,Kwon, Jeong-Tae,Lim, Hyo-Jae 한국조명전기설비학회 2007 조명·전기설비학회논문지 Vol.21 No.6
본 논문에서는 선형유도전동기의 전자기력에 의해 용융 금속을 이송할 수 있는 전자기 펌프에 대하여 특성 해석 및 실험 결과에 대하여 제시하였다. 선형유도전동기에서 발생하는 전자기력과 전자수력학(MHD) 현상을 결합하여 용융 금속의 이송 특성을 해석하였다. 실험은 용융 아연을 대상으로 하였으며, 해석 결과와 비교 검토하였다. This paper presents the characteristics analysis and experiment of the electromagnetic pump using linear induction motor(LIM Pump) which can transfer the molten metals by the electromagnetic force. The characteristics of LIM Pump are analysed solving the magneto-hydro-dynamic(MHD) equation at various magnetic flux. The molten zinc is used in the experiment and the results we compared with the analysis.
임효재(Hyojae Lim),손병후(Byonghu Sohn) 한국지열·수열에너지학회 2021 한국지열에너지학회논문집 Vol.17 No.2
This paper presents the heating performance analysis results of a heat pump system using a dual heat source. In this paper, a dual heat source refers to the ground-coupled heat exchanger using both a surface water heat exchanger (SWHE) and a vertical ground heat exchanger (VGHE). In order to evaluate the system performance, we installed a monitoring system to measure the temperature and power consumption of a heat pump and then collected operation data with 4 different load burdened ratios of the dual heat source heat exchanger. During the whole measurement period, the average heating capacity of a water-to-water heat pump unit was 37.3 kW. In addition, the compressor of the heat pump consumed 9.4 kW of power, while the circulating pump of the dual heat source heat exchanger used 6.7 kW of power. Therefore the average heating coefficient of performance (COP) for the heat pump unit was 4.0, while the entire system including the circulating pump was 2.7. Finally, the parallel use of SWHE and VGHE was beneficial to the system performance; however, further researches are needed to optimize the design data for various load ratios of the dual heat source heat exchanger.
지중열교환기 설치 조건이 지중 유효 열전도도와 보어홀 열저항에 미치는 영향
임효재(Hyo Jae Lim),공형진(Hyoung Jin Kong),강성재(Sung Jae Kang),최재호(Jae Ho Choi) 대한설비공학회 2011 설비공학 논문집 Vol.23 No.2
A ground loop heat exchanger in a ground source heat pump system is an important unit that determines the thermal performance of a system and its initial cost. A proper design requires certain site specific parameters, most importantly the ground effective thermal conductivity, the borehole thermal resistance and the undisturbed ground temperature. This study was performed to investigate the effect of some parameters such as borehole lengths, various grouting materials and U tube configurations on ground effective thermal conductivity and borehole thermal resistance. In this study, thermal response tests were conducted using a testing device to 9 different ground loop heat exchangers. From the experimental results, the length of ground loop heat exchanger affects to the effective thermal conductivity. The results of this experiment shows that higher thermal conductivity of grouting materials leads to the increase effective thermal conductivity from 22 to 32%. Also, mounting spacers have increased by 14%.
지하수 열원 복수정 지열 열펌프 시스템의 성능에 관한 실험적 연구
임효재(Hyo Jae Lim),권정태(Jeong-Tae Kwon),김창업(Chang Eob Kim),공형진(Hyoung Jin Kong),박성구(Seong Koo Park) 대한설비공학회 2009 설비공학 논문집 Vol.21 No.8
Ground water source heat pump system is the oldest one of the ground source heat pump systems. Despite of this, little formal design information has been available until recently. The important design parameters for open system are the identification of optimum ground water flow, heat exchanger selection and well pump. In this study, the capacity of 50 RT system of two well type ground water heat pump system was used. As a result, static water level was -7 m and the level during the heating operation was -32 m, cooling operation was -40 m. The initial static water level recovered within 48 hrs. The temperature of ground water is 15.6 ℃ for heating season and 16.2 ℃ for cooling season and does not depend on the outdoor temperature. Operation efficiency of the system shows that, COP 3.1 for heating and COP 4.2 for cooling.
지표수 열교환기 적용 지열 히트펌프 시스템의 냉방 성능
임효재(Hyo Jae Lim),공형진(Hyoung Jin Kong),손병후(Byonghu Sohn) 대한설비공학회 2017 설비공학 논문집 Vol.29 No.6
Commercial buildings and institutions are predominantly cooled, thereby dissipating excess heat to a vertical ground heat exchanger (VGHE), than heat extracted over an annual cycle. Surface waters, such as lakes and ponds, provide a cost-effective means of reducing the VGHE length, and in balancing the thermal loads to the ground. This paper presents the measurement and analysis of the cooling performance of ground-coupled heat pump (GCHP) system, using surface water heat exchanger (SWHE) submerged in an artificial pond. In order to measure the performance of the system, we installed monitoring equipment, including sensors, for assessing the temperature and power consumption, after which the operation parameters were determined. The results from the thermal performance test for the SWHE indicate that the temperatures at the outlet of the SWHE and within the pond were affected by outdoor air temperature. In addition, the results reveal similar variation trends on temperatures; however, the peak temperatures of the SWHE were somewhat greater than those of outdoor air, due to the thermal capacity of the pond. Analyzing the cooling performance over the measurement period, the average coefficient of performance (COP) of heat pump was found to be 5.71, while that for the entire system was 2.99.
지열원 시스템 히트펌프의 냉방 성능 특성에 관한 실증 연구
임효재(Hyo-Jae Lim),강신형(Shin-Hyung Kang),최재호(Jae Ho Choi),최종민(Jong Min Choi),문제명(Jemyung Moon),권영석(Youngseok Kwon),권형진(HyungJin Kwon),김록희(RockHee Kim) 대한설비공학회 2008 대한설비공학회 학술발표대회논문집 Vol.2008 No.2
Recently, small and medium-sized buildings have employed a multi-heat pump. The major benefits of the mulit-heat pump over a conventional system are that it is easier system to maintain along with a diversification of facility use, and high comfortability. The performance of multi-heat pump systems can be enhanced by using geothermal energy instead of air source energy. This paper describes the multi-heat pumps applied in an ground source heat pump system for an actual building. The performance of a ground source multi-heat pump installed in the field was investigated in cooling mode. The maximum COP of the systems with single U-tube and double tube ground loop heat exchangers were 6.6 and 6.0, respectively. It is suggested that the new algorithms to control the flow rate of secondary fluid for ground loop heat exchanger have to be developed in order to enhance the performance of the system.