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Changwon, South Korea

Park H.,STX Engine Co. | Kim J.,Korea Railroad Research Institute
International Journal of Precision Engineering and Manufacturing - Green Technology | Year: 2016

The objective was the development of an energy harvester for the hot-box detector of the HEMU-430 project high-speed train in Korea. In this study, we attempt the development of energy harvesters that incorporate a monitoring system in the train wheel bearing. We verified the use of electromagnetic induction as an effective method for harvesting energy from low-frequency vibration through the environmental test. We applied mechanical, electromagnetic, and electrical modeling processes to maximize the relative motion between core parts, and the optimization should be done using a mass spring damping model. We analyzed the wheel vibration sources at speeds between 300 and 400 km/h, fabricated a prototype of the energy harvester, and used a reinforced material for the practical application. Based on analyses of the static and fatigue properties of different materials, we decided the proper material as Invar 42. We also secured the structural stability by FEM. Our onboard measurement revealed that the generation characteristics of a narrow band resonance module capable of operating at a specific resonance frequency could be verified. The results of environmental tests confirmed that the Invar 42 cantilever beam-type electromagnetic induction energy harvester could be used as a model of a highly durable system. © 2016 Korean Society for Precision Engineering.

Lim K.B.,Hanbat National University | Lee S.H.,Hanbat National University | Lee C.H.,STX Engine Co.
Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering | Year: 2010

In this article, the operating stability and application of a water-heat storage system for detecting frost formation in an air-source heat pump were investigated, and the most efficient initiation point of the defrosting cycle was determined. This method of using the mechanism of frost formation and hot-gas and reverse-cycle defrosting was investigated in terms of the operating stability of a heat pump. In this study, when the air-source heat pump is in heating mode, an analogized interrelation for the temperature and humidity of the outside air for frost cognition is determined from a psychometric chart. In this study, an air-source heat pump was applied to a water heat storage system and evaluated the performance of its operation. The performance of the air-source heat pump presented in this study had energy production about 18.6 per cent greater than that of a heat pump for which a time step method of defrosting was employed.

Lee C.H.,STX Engine Co. | Lee K.H.,Hanyang University | Lim K.B.,Hanbat National University
International Journal of Automotive Technology | Year: 2010

We investigated the effects of injection parameters such as injection pressure, ambient pressure, and ambient temperature on spray characteristics. We calculated the turbulence occurring point (tc), defined as the time required to generate a vortex, and the deceleration point (tb), defined as the time when spray penetration begins to decelerate, to elucidate the breakup mechanism of the test injectors. The spray velocity coefficient (Cv) was obtained to evaluate the spray characteristics. As the ambient pressure increases in the case of a slit injector, Cv decreases. We investigated the effects of nozzle tip shape according to injection pressure, ambient pressure, and fuel properties on spray characteristics and provide a Cv value of 0.38 for the swirl injector with a spray angle of 60° and the slit injector under atmospheric conditions. The value of Cv in the case of a slit injector was reduced by increasing the ambient pressure. Our results suggest that Cv of a swirl injector is constant regardless of changes in ambient pressure, injection pressure, and fuel properties. On the other hand, Cv of a slit injector is altered by changes in ambient pressure. © 2010 The Korean Society of Automotive Engineers and Springer-Verlag Berlin Heidelberg.

Ka M.-H.,Yonsei University | Baskakov A.I.,Moscow Power Engineering Institute | Terechov V.A.,Moscow Power Engineering Institute | Kononov A.A.,STX Engine Co.
IEEE Geoscience and Remote Sensing Letters | Year: 2013

In this letter, we introduce the possibility of the sea-surface slope measurements using second-order statistics of return waveforms from sea surface in a continuous-wave radar scatterometer. It has been shown that the estimation of the variance of sea-surface slopes can be obtained by measuring the signal power or the power-spectrum width of return waveforms. We found that the power-spectrum-width-based estimation approach is more sensitive to the variance of the sea-surface slope for weak sea-surface disturbances in contrast to the power-based one. © 2004-2012 IEEE.

Lim K.B.,Hanbat National University | Lee S.H.,Hanbat National University | Lee C.H.,STX Engine Co.
Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering | Year: 2010

Ground-source heat pumps (GSHPs) are attractive alternatives to conventional heating and cooling systems owing to their higher energy utilization efficiency. GSHPs, also known as geothermal heat pumps, are a promising new technology that has been used for the last few years in the Korean market. A geothermal energy system has been developed over the last two years and a ground-heat-source water thermal-storage heat-pump cooling and heating system in Gu-mi city was built. Trial performance tests were conducted on the system. The actual proof examination was accomplished and the performance of the system was investigated. The coefficient of performance of the heat pump unit was 4.29 for cooling and 3.97 for heating. Thus, the presented system is expected to be used for energy savings and active alternative energy use.

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