• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1709-1716
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• 2003

Stirling engine is a heat engine with a high potential efficiency, multi-fuel capability, its low emission, quiet operation, very low maintenance requirement and long life. The Stirling cycle can ideally achieve optimum thermodynamic efficiency of the Carnot cycle. But the actual efficiency of practical reciprocating Stirling engine is much less than that of ideal Stirling cycle due to several mechanical limits. This paper presents a new-type Stirling engine employing the scroll mechanism superior to the reciprocating Stirling engine. The new-type Stirling engine is characterized as traits of continuous and wholly seperated compression and expansion, one-way flow, direct cooling and heating through the extensive surfaces of scroll wraps. By means of this traits, the new-type Stirling engine can achieve thermodynamic cycle closer to the ideal Stirling cycle and have many mechanical merits. Also, the new-type Stirling cycle can be applied as Stirling refrigerator and Duplex Stirling machine.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.5
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• pp.76-85
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• 2000

Stirling cycle was actualized as so called ‘hot air engine’. It has been focused again lately as one of measures for exhaust gas emission problem, but as small power engine because of its method of heat addition. Recently marine power plants commenced to meet a stringent environmental restrictions by international convention, Marpol so that diesel engines as main and auxiliarly power plants are urged to be reformed to reduce NOx emission. Author devised a compression ignition engine as a large marine power plants combined with turbo charger based on stirling cycle, and analyzed the performance by means of basic thermodynamic calculation. Analyzed in this paper, were theoretical efficiency, mean effective pressure, required equivalence ratio, gas turbine power ratio, maximum pressure, states of turbo-charger inlet gas and exhaust gas, manifesting that the engine could be proposed as one of the future power plants of marine use.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.169-173
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• 2008

Stirling engine is a promising heat engine with a high efficiency, muti-fuel capability, low emission, quiet operation, very low maintenance and long life. As one of the promising applications, solar power system based on the Stirling dish, providing net solar-to-electric conversion efficiencies reaching 30%, can operate as stand-alone units in remote locations or can be linked together in groups to provide utility-scale power. This paper introduced a new Scroll-type Stirling engine, being developed for solar power, superior to conventional Stirling engines. The Scroll-type Stirling engine is characterized as traits of continuous and wholly separated compression and expansion; one-way flow system; direct cooling and heating the fluid in the working spaces through the extensive inner surfaces of scroll wraps. All theses traits contribute to achieving thermodynamic cycle closer to the ideal Stirling cycle (exactly speaking, Ericsson cycle).

• Progress in Superconductivity and Cryogenics
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• v.19 no.4
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• pp.12-17
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• 2017

Design of Reverse Stirling Cycle based refrigerator can be predicted by Schmidt theory as a useful tool and by experiment it is found that for practical purposes the power and efficiency predicted by this analysis are about 35% of the actual values. Therefore, appropriate provision is to be made for getting the realistic result with the minimum deviation. The present paper first investigates the suitability of application of Schmidt design analysis for standard ZIF-1002 and PLN-106 Single cylinder Cryogenerator model. As the result is found to be optimistic, the same design procedure is applied for the design of a separate Cryogenerator for generating a cooling effect which is sufficient to produce 7 kg per hour liquid nitrogen using an indigenous condenser of 80% effectiveness. The paper describes all the details of the design methodologies and relevant results are found to be satisfactory.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.6
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• pp.648-655
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• 2014

This paper describes the continuing effort to develope a single acting free-piston Stirling engine/alternator combination for use of the household cogeneration. Free piston Stirling engines(FPSE) use variations of working gas pressure to drive mechanically unconstrained reciprocating elements. Stirling cycle free-piston engines are driven by the Stirling thermodynamic cycle which is characterized by an externally heated device containing working gas that is continuously re-used in a regenerative, reversible cycle. The ideal cycle is described by two isothermal process connected by two constant volume processes. Heat removed during the constant volume cooling process is internally transferred to the constant volume heating process by mutual use of a thermal storage medium called the regenerator. Since the ideal cycle is reversible, the ideal efficiency is that of Carnot. Free-piston Stirling engine is have no crank and rotating parts to generate lateral forces and require lubrication. The FPSE is typically comprised of two oscillating pistons contained in a common cylinder. The temperature difference across the displacer maintains the oscillations, and the FPSE operate at natural frequency of the mass-spring system. The power is generated from a linear alternator. The purpose of this paper is to describe the design process of the single acting free-piston Stirling engine/alternator. Electrical output of the single acting free-piston Stirling engine/alternator is about 0.95 kW.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.6
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• pp.1547-1555
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• 1993

An experimental study on convection heat transfer characteristics from a heated tube to an oscillating flow has been carried out, . This problem is of particular interest in the design of heat exchangers in Stirling cycle machines. Experimental system has been developed to measure temporal variations of temperature inside a heater tube during oscillating modes in a Stirling cycle machine. The dependence of temperature distributions and heat transfer rates on the oscillating frequency as well as the swept volume ratio and the mean pressure of a Stirling cycle machine is investigated in detail. The experimental results indicate that the measured temporal variations of temperature become nearly sinusoidal. The amplitude of temperature variation in the core of the tube is much more substantial than that near the tube wall, whereas the reverse is true for pulsating flows. It is also found that the heat transfer rate is increased significantly as the oscillating frequency or oscillating amplitude or the mean pressure in a tube is increased.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2000.02a
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• pp.81-84
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• 2000

This paper presents operating process and design method on the linear compressor Stirling cryocooler for cooling infrared detector. The free piston-type Stirling cryocooler, which applies 1) the Stirling cycle for refrigeration, 2) linear motors for driving, 3) flexure bearings for support systems, and 4) fine gap for clearance seals, is the most suitable design for a mechanical cryocooler utilized in a night vision environment.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.4
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• pp.1426-1436
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• 1996

The effectiveness of the regenerator pertaining to Stirling cycle machines is studied by analyzing the heat transfer characteristics of the oscillating flow in a tube, and a new consistent definition of the regenerator effectiveness can be expressed by the ratio of the heat transfer in axial direction (Q$\_$axial/) to that in transverse direction (Q/su w/), and its approximate form is obtained as a function of Nusselt number for practical utility. Since an approximate value of the ratio Q$\_$axial//Qsub w/ can be expressed in terms of the time-averaged rather than transient temperatures, this expression is useful to estimate the heat transfer coefficient in the Stirling machine regenerator experimentally.

• 연구논문집
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• s.30
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• pp.25-32
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• 2000

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). A Stirling cryocooler is relatively compact, reliable, commercially available, and uses helium as a working fluid. The FPFD stirling cryocooler consists of two compressor pistons driven by linear motors which makes pressure waves and a pneumatically driven displacer piston with regenerator. The FPFD Stirling cryocooler employs 1) the Stirling cycle for refrigeration, 2) linear for driving the cryocooler, 3) spring and gas support systems, and 4) fine gap for clearance seals. It is the most suitable design for a mechanical cryocooler utilized in night vision environment. In order to get optimum operating frequency, natural frequency of piston and displacer, optimum phase angle between piston and displacer, cooling capacity, performance tests of the Stirling cryocooler by the frequency characteristics were performed.

• The KSFM Journal of Fluid Machinery
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• v.18 no.1
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• pp.37-43
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• 2015

A Beta-type Stirling engine is developed and tested on the operation stability and cycle performance. The flow rate for cooling water ranges from 300 to 1500 ml/min, while the temperature of heat source changes from 300 to $500^{\circ}C$. The internal pressure, working temperatures, and operation speed are measured and the engine performance is estimated from them. In the experiment, the rise in the temperature of heat source reduces internal pressure but increases operation speed, and overall, enhances the power output. The faster coolant flow rate contributes to the high temperature limit for stable operation, the cycle efficiency due to the alleviated thermal expansion of power piston, and the heat input to the engine, respectively. The experimental Stirling engine showed the maximum power output of 12.1 W and the cycle efficiency of 3.0 % when the cooling flow is 900 ml/min and the heat source temperature is $500^{\circ}C$.