• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.7
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• pp.1751-1758
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• 1994

A new set of governing equations is derived for the dynamic analysis of the Free-Piston Stirling Engines(EPSE). Equations from the ideal adiabatic model for the thermodynamic analysis of the working fluid are incoporated with the equations of motion for the moving masses of the system, resulting in a set of nonlinear differential equations. The coupled set of equations are numerically integrated with proper intial conditions to obtain a steady state response of the engine. The proposed method is compared with the conventional method of analyzing EPSE based mainly on the ideal isothermal model. The results clearly shows the limitationsl of the conventional methods and the relative advantages of the method proposed in the present study.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.2198-2204
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• 2003

In order to make a match of the insufficient direct solar radiation, in this study, the target output is lowered to 9 kW smaller than 25 kW in former studies. It is also necessary to match the collector/receiver with engine/generator systems to accomplish the power level of a system. The simulation analyses of a dish solar power system with stirling engine are totally carried out to predict the system performance with the designed values. In addition, an influence of direct solar radiation on system performance and operation control is discussed in simulation. It is found that the diameter of concentrator could be made small to 8 m regardless of slope errors with 2.5 and 5.0 mrad radiation, and the operation range of mean pressure control. is wide even if the direct solar radiation is a quit low.

• Journal of applied mathematics & informatics
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• v.36 no.5_6
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• pp.435-446
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• 2018

Using the theory of combinatoric convolution sums, we establish some arithmetic identities involving Liouville functions and restricted divisor functions. We also prove some relations involving restricted divisor functions and Stirling numbers of the first kind for divisor functions.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.02a
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• pp.156-159
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• 2003

A free piston and free displacer(FPFD) Stirling cryocooler for cooling infrared and cryo-sensors is currently under development at KIMM(Korea Institute of Machinery ＆ Materials). Our coolers are specifically designed to work in the thermal imaging device and to meet requirements such as cooling capacity, COP and high reliability. In this work, Stirling cryocooler is designed, manufactured and fabricated, and performance characteristics are investigated. This cooler delivers approximately 0.5W cooling at 77K for 30W ∼ 40W of input power from AC power supply. And, after the climate performance and reliability for the cryocooler is discussed, operating test without cooling load at the cold end is performed.

• Progress in Superconductivity and Cryogenics
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• v.4 no.2
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• pp.58-62
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• 2002

The purpose of this study is to analyze the charging gas effect on the resonance and performance characteristics of the linear compressor for small scale FPFD Stirling refrigerator. To ensure high performance of FPFD type Stirling refrigerator, the operating frequency of the refrigerator should be around the natural frequency of compressor. The gas spring effect which is induced from Pressure change in cylinder due to motion of pistons has significant effect on the natural frequency of the compressor. The numerical results show the linear compressor has high natural frequency when the charging pressure of working fluid is high and the stroke of compressor, current, input power and efficiency of compressor were shown with different operating conditions.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.10
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• pp.555-561
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• 2013

The effects of applying the micro CHP system to the domestic sector in Korea were investigated using annual cooling and heating demand data. Four prime movers, micro gas turbine, PEMFC, gas engine and Stirling engine, were compared for three operational modes. Two way buy-back was assumed for both electricity and heat. The Stirling engine gave the lowest $CO_2$ emission per energy for 300kWh monthly electricity production. However, PEMFC became more effective when considering PURPA criteria. PEMFC generated the least greenhouse gas with higher electrical efficiency for cooling. The Stirling engine, however, became competitive for heating with higher total efficiency.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.177-183
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• 2008

For 10 kW-class Stirling engine using scroll expander and scroll compressor, considerations on thermal expansion of the fixed and orbiting scroll members of the scroll expander due to high gas temperature at the expander inlet has resulted in adopting of the keys between the fixed scroll and main frame for the fixed scroll side and spring type insertion between the orbiting scroll base plate and supporting holders for orbiting scroll side. Dynamic analysis on the fixed and orbiting scroll members and the shafts of the scroll expander showed that using of these devices for complying thermal expansion caused large variations of the forces acting on the fixed scroll keys and on the power transmitting shafts and also on the shaft bearings.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.10a
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• pp.316-319
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• 2003

Cryogenic refrigerator system is necessary for cooling the superconducting rotor. Among the various cryogenic refrigerator systems, on-board hybrid pulse tube cryocooler is designed for cooling the superconducting rotor. Hybrid pulse tube cryocooler is composed of pulse tube cryocooler and Stirling cryocooler. This Stirling cryocooler precools the middle point of regenerator to obtain lower temperature at cold part of pulse tube cryocooler. In this paper, only Stirling cryocooler is on-boarded then rotated by motor for various rotating speeds and heat loads at cold part of Stilting cryocooler. Through this experiment the feasibility of the on-board cryocooler is investigated.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2001.05a
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• pp.122-128
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• 2001

The simulation analyses of a dish solar power system with stirling engine in this study are applied to system performance prediction if four different test sites; Seoul, Pusan and Cheju in Korea, and Naha in Japan. The effects of difference of concentrator type such as monolithic and stretched-membrane construction on system efficiency are also evaluated. The total amount of generated power for a year depends on the site. However the total maximum system efficiency in every site is approximately 16% and there isnt striking difference. It is also found that the maximum collector efficiency of stretched-membrane concentrator is about 3∼15% lower than that of the monolithic type.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1999.11a
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• pp.149-154
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• 1999

This paper describes a passive safety injection system with free piston Stirling pump working withabundant decay heat in the nuclear reactor during the hypothetical accident. The water column in the tube assembly connected from the hot chamber to the cold chamber in the pump oscillates periodically due to thermal volume changes of non-condensable gas in each chamber. The oscillating pressure in the water column is converted into the pumping power with a suction-and-bleed type valve assembly. In this paper a dynamic model describing the frequency of oscillation and pumping pressure is developed. It was found that the pumping pressure is a function of the temperature difference between the chambers. Also, the frequency oscillation depends on the length of the tube with water column.