• The KSFM Journal of Fluid Machinery
• /
• v.19 no.2
• /
• pp.43-48
• /
• 2016

This study proves successes of Energy Service Company (ESCO) business by heat pump performance test. The purpose of ESCO business is recover investment costs through saving energy from installation of energy reduction facility. The most important technology assessment items are heat recovery and generator output. Experimental result shows that increase quality of heat recovery (11.52Gcal/h), while decrease generator output (0.234kw). In its final analysis, the ESCO business is successful according to our data.

• Solar Energy
• /
• v.12 no.3
• /
• pp.126-136
• /
• 1992

In this paper an EGD generator of small capacity with the operating gases of $O_2,\;N_2$ and air is made and the electric characteristics in relation to energy conversion range length, corona current and gas pressure are investigated. The results are as follows: 1. There is a critical value in conversion range length for maximum open voltage and the critical value increases with fluid velocity. 2. The open voltage increases approximately linearly with corona current. 3. There is a critical value in the gas pressure for maximum open voltage and this pressure of gas decreases with fluid velocity in constant conversion range length.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.51 no.8
• /
• pp.391-397
• /
• 2002

This paper presents a modeling and simulation of a PI controller for maximum power extraction of a grid-connected wind energy conversion system with a link of a rectifier and an inverter. It discusses the maximum power control algorithm fnr a wind turbine and proposes, in a graphical form, the relationships of wind turbine output, rotor speed, power coefficient, tip-speed ratio with wind speed when the wind turbine is operated under the maximum power control. The control objective is to always extract maximum power from wind and transfer the power to the utility by controlling both the Pitch angle of the wind turbine blades and the inverter firing angle. Pitch control method is mechanically complicated, but the control performance is better than that of the stall regulation method. The simulation results performed on MATLAB will show the variation of generator's rotor angle and rotor speed, pitch angle, and generator output.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.52 no.8
• /
• pp.413-419
• /
• 2003

The paper presents a simulation model and analysis of a grid-connected variable speed wind energy conversion scheme (VSWECS) using the PSCAD/EMTDC software. The modeled system uses a variable speed drive, a fixed pitch angle, a synchronous generator as a wind generator and an AC-DC-AC conversion scheme, which facilitates the wind generation to efficiently operate under varying wind speed while connected to the distribution network. The power output of the WECS is controlled by the AC-DC-AC conversion scheme, the objective of which is to capture the maximum active power under varying wind conditions and to keep the voltage magnitude of the terminal bus at a specific level. Aerodynamic models are applied for a wind turbine model. An simulation analysis of the scheme in terms of its responding to wind variations is also presented.

• Journal of Sensor Science and Technology
• /
• v.20 no.2
• /
• pp.102-106
• /
• 2011

This paper presents a design and analysis of an electromagnetic micro generator which can convert low frequency vibration energy to electrical power. The design aspects of the micro generator comprised planar spring, Cu coil and a permanent magnet(NdFeB). Threetype spring designs and four materials(Parylene, FR-4, Cu and Si) were compared to find resonance frequency. It was found that the resonance frequency will be changed according to the spring shape and material. Mechanical and magnetic parameters had been adjusted to optimize the output power through a comprehensive theoretical study.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2006.09a
• /
• pp.585-586
• /
• 2006

Several chemicals were studied to suppress the damage due to stress corrosion cracking (SCC) of steam generator (SG) tubes in nuclear power plants. The effects on the SCC of the compounds, $TiO_2$, TyzorLA and $CeB_6$, were tested for several types of SG tubing materials. The test with the addition of $TiO_2$ and $CeB_6$ showed an effect in decreasing the SCC for the SG tubing material. However, $CeB_6$ caused some more SCC for Alloy 800. The penetration property into a crevice of the inhibitors was investigated by using Alloy 600 specimens with different gap.

• Proceedings of the KIEE Conference
• /
• 2005.07b
• /
• pp.1047-1049
• /
• 2005

Hydraulic power plant is operated for peak load and frequently start-stop because of no continuous operation. So the fault can happen due to field voltage swing in the middle of starting or reactive power swing on the line. On this research, we want to analyze that this status influence on line and generator. we hope this research can contribute to the power quality improvement.

• Nuclear Engineering and Technology
• /
• v.30 no.6
• /
• pp.555-567
• /
• 1998

Alloy 600 and 690 steam generator tubes fabricated in Korea were evaluated by flare tests according to ASTM standards. The stress acting in the tube elements during the tests was predicted. All the tubes, including alleys 600 and 690, satisfied the requirement of a 30% or 35% O.D expansion. Flow curves obtained from the flare test were found to be higher in alloy 690 tubes than in alloy 600 ones. The difference between alloy 600 and 690 tubes increased gradually with flaring percentage (F.P,%). An effective stress corresponding to mean yield stress was introduced and calculated. It showed that the prediction values were in good agreement with the measured ones for all the 690 and 600 alloy tubes. It became possible to predict the amount of acting stresses within tubes during expansion process.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
• /
• 2007.11a
• /
• pp.226-231
• /
• 2007

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.16 no.2
• /
• pp.7-15
• /
• 2017

Recently, an electricity sensor system has been installed and operated to prevent failures and accidents by identifying whether a transformer is normal in advance of failure. This electricity sensor system is able to both measure and monitor the transformer's power and voltage remotely and send information to a manager when unusual operation is discovered. However, a battery is required to operate power detection devices, and battery systems need ongoing management such as regular replacement. In addition, at a maintenance cost, occasional human resources and worker safety problems arise. Accordingly, we apply a linear electromagnetic generator using vibration energy from a transformer for an electric sensor system's drive in this research and we conduct optimal design to maximize the linear electromagnetic generator's power. We consider design variables using the provided design method from Process Integration, Automation, and Optimization (PIAnO), which is common tool from process integration and design optimization (PIDO). In addition, we analyze the experiment point from the design of the experiments using "MAXWELL," which is a common electromagnet analysis program. We then create an approximate model and conduct accuracy verification. Finally, we determine the optimal model that generates the maximum power using the proven approximate kriging model and evolutionary optimization algorithm, which we then confirm via simulation.