• Journal of the Korean Geotechnical Society
• /
• v.29 no.9
• /
• pp.31-41
• /
• 2013

The use of energy pile foundation has increased for economic utilization of geothermal energy. In particular, coil-shaped ground heat exchanger (GHE) is preferred to the conventional U-shaped exchanger to ensure better efficiency of heat exchange rate. This paper presents a numerical and experimental study on the heat transfer behavior of PHC energy piles. Field thermal performance tests (TPTs) were conducted for the PHC energy piles installed in a partially saturated weathered granite soil deposit, in which two types of GHEs were considered: W and coil shaped GHEs. Besides, three-dimensional finite element analyses were also conducted, and the results were compared with the experimental results. According to the results of TPT and numerical analyses, the coil shaped GHE showed 10~15% higher heat exchange rate than the W type GHE in the PHC energy piles.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.11 no.3 s.55
• /
• pp.63-72
• /
• 2007

The Emergency Diesel Generator (EDG) is a very important equipment for the safety of a Nuclear Power Plant (NPP). In this study, the operating vibration of three kinds of EDG systems was measured. The target EDG systems are Yonggwang 5 unit and Ulchin 2 and 3 units. The Yonggwang 5 and Ulchin 3 unit EDG systems are the same type but the foundation systems are different. One is an anchor bolt type and the other is a spring and viscous-damper type. The purpose of these measurements is for a verification of the vibration isolation effect depending on the foundation system. As a result, It can be said that the spring and viscous damper system of the EDG performed better for the vibration isolation than that of anchor bolt type.

• Proceedings of the KIEE Conference
• /
• 2006.04b
• /
• pp.115-117
• /
• 2006

The detent force by end-effect has a bad influence on moving coil type Permanent Magnet Linear Synchronous Motor(PMLSM). So, the reduction of detent force by end-effect is especially required for improvement of thrust characteristics. In this paper, in order to reduce detent force by end-effect the auxiliary teeth is installed at the end part of mover and it is optimized by using neural network.

• Proceedings of the KIEE Conference
• /
• 2007.04c
• /
• pp.116-118
• /
• 2007

In this paper, the notch of teeth, the shape changing and skew of permanent magnet are used to reduce the detent force. And addition, overhang of permanent magnet is applied to increase thrust because thrust is decreased by skew. As the results, detent force is decrease greatly about 98(%). And, the ripple ratio of thrust is decreased from 11.34(%) to 0.25(%).

• Proceedings of the KIEE Conference
• /
• 2001.07b
• /
• pp.580-582
• /
• 2001

In moving coil LOA, the variation of mover position and the consequent changes of coil flux path affect the coil inductance because of unbalanced magnetic circuit. Furthermore, the armature field shifts and distorts the airgap flux density distribution due to the magnet alone by a certain amount, which cause the unbalanced reciprocating force. In this paper, we propose the reduction method of armature reaction and coil inductance. The proposed LOA has the shorted ring the saturated core, the double coil, and Halbach array.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.55 no.9
• /
• pp.459-464
• /
• 2006

The detent force by end-effect has an undesired influence on moving coil type Permanent Magnet Linear Synchronous Motor(PMLSM). So, the reduction of detent force by end-effect is especially required for the improvement of thrust characteristics. In this paper, in order to reduce detent force by end-effect, the auxiliary-teeth is installed at the end part of mover. It is also analyzed by Finite Element Analysis(FEA) and optimized by using neural network. By comparison, the detent force is reduced about 41.4[%] comparing to that of basic model.

• The Magazine for Energy Service Companies
• /
• s.39
• /
• pp.70-73
• /
• 2006

클린 에너시 시장 "2015년 1672억 달러로 성장"/대림산업 양주 택지지구에 구역형 집단에너지 사업/산자부 에너지진단의무화 입법예고/동아전람 '제2회 동아 빌딩박람회'참가업제 모집/에너지기술연 제지설비 응축열 재활용 '열교환기'상용화/산자부 환경친화 산업구조개선 법률 개정/미국 냉동공조공학회 이진원 교수·이상민 박사에 최고논문상/광주시 그린빌리지, 수소연료전지 본격가동/대전 신동아파트 소형열병합 ESCO자금 상황 '끝'/기획예산처 교육세 일부 환경,에너 지 분야에 활용/유기태양전지 개방 '청신호'/중소기업청 신기술 제품 공공구매 본격 확대/에노지관리공담 혁신도시 건설을 위한 신·재생에너지보급 촉진 간담 회 개최/산자부 온실가스 배출통계 시스템 구축

• Proceedings of the KIEE Conference
• /
• 2006.07b
• /
• pp.905-906
• /
• 2006

This paper deals with the dynamic simulations and experiments of moving-coil linear actuator with/without spring. Dynamic simulation algorithm is established from the voltage and motion equation. Finally, for various values of frequency, dynamic simulation results for characteristics of current and displacement of moving-coil linear actuator with and without spring are presented and confirmed through the experiments.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.50 no.6
• /
• pp.273-281
• /
• 2001

In order to overcome the demerit and to improve the operation characteristics of Moving Coil type Linear Oscillatory Actuator(MC-LOA) with single-pole permanent magnet, this paper presents two models having the balanced magnetic circuit by multi-pole permanent magnet. They are short coil type with two-pole single-sided and two-ple double-sided permanent magnet. The characteristics between single-pole and multi-pole permanent magnet type MC-LOA are compared. As a result, multi-pole type MC-LOA has more merits than single-pole type about operation characteristics improvement and machine volume. The characteristics analysis is performed by their dynamic analysis composed of kinetic and electric equations and Finite Element Method(FEM). The propriety of multi-pole type MC-LOA model is verified with analysis results.

• Journal of Industrial Technology
• /
• v.20 no.B
• /
• pp.125-130
• /
• 2000

Heat dissipation technology using flow resonant phenomenon is a kind of new concept in heat transfer area. A vibration exciter is needed to generate air turbulence which has the natural shedding frequency of heat system. A mechanical vibrating device for the air flow oscillation is introduced, which is driven by a moving coil actuator. An analytical dynamic model for this mechanical vibration exciter is presented and its validity is verified by the comparison with experimental data. Values of some unknown system parameters in the analytic model are estimated through the system identification approach. Based on this mathematical model, a high bandwidth vibration phase, it turns out the high modal resonant characteristics of vibrating plate are the major barrier against obtaining a high bandwidth vibration exciter.