• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.6
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• pp.716-724
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• 1999

In co-orbiting scroll compressor, the two scroll members are to orbit with independent radii, producing a relative orbit motion between them. One scroll member is driven by the crank mechanism while the motion of the other member is determined by geometrical constraints and reacting forces. This paper presents an analytical study on the performance of a co-orbiting scroll compressor. The following results have been obtained: Radial contact force between the scroll wraps is virtually free from the centrifugal force of the orbiting scroll member. The frictional losses are somewhat increased due to the complicated drive mechanism, yielding to a little lower EER compared to conventional radially compliant scroll compressors .

• Bulletin of the Korean Mathematical Society
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• v.53 no.6
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• pp.1707-1714
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• 2016

Let $C{\subset}{\mathbb{P}}^r$ be a nondegenerate projective curve of degree d > r + 1 and of maximal regularity. Such curves are always contained in the threefold scroll S(0, 0, r - 2). Also some of such curves are even contained in a rational normal surface scroll. In this paper we study the minimal free resolution of the homogeneous coordinate ring of C in the case where $d{\leq}2r-2$ and C is contained in a rational normal surface scroll. Our main result provides all the graded Betti numbers of C explicitly.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.5 no.4
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• pp.306-317
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• 1993

In this study, a performance comparison of scroll compressor for various refrigerants(CFC-12, HCFC-22 and HFC-134a) has been numerically carried out. The thermodynamic properties have been calculated by using the recent experimental equations and the performance has been investigated qualitatively at the same geometric specifications and operating conditions of scroll compressor. The results are as follows; HFC-134a has the highest compression ratio of 5.40. The mass flow rate of HCFC-22, which affects the cooling capacity of refrigerant system, is higher than that of other refrigerants. HFC-134a has the highest adiabatic efficiency in comparison with CFC-12 and HCFC-22.

• Proceedings of the Korean Vacuum Society Conference
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• 2002.02a
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• pp.32-32
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• 2002

• Journal of Korean Vacuum Science & Technology
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• v.6 no.4
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• pp.158-161
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• 2002

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.242-247
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• 2000

In this study, the Rayleigh's energy method and the Rayleigh-Ritz method on the basis of Flugge's shell theory was used to analyze the dynamic characteristics of the scroll compressor housing with clamped boundary condition. The frequencies and mode shapes from theoretical calculation were compared with those of commercial finite element code, ANSYS. In order to validate the theory, modal test was also performed by impact test and FFT analysis.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.12
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• pp.776-781
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• 2011

The rapid increases in global energy demand and global warming need renewable energy sources such as solar thermal energy, biomass energy and waste heat. A ORC-based micro-CHP system(< 10 kWe) is one of the effective means to use renewable energy and solve energy problems because of its compactness, flexibilities and lower cost compared to other systems. The most important core components of the ORC is the expander which has a strong effect on the cycle efficiency. In the range of power output from 1 to 10 kW, the scroll expander is a good choice due to its performance and reliability. In this study, we have carried out an experimental study on an ORC equipped with oil-free scroll expander working with refrigerant R134a. We have measured power output and thermal efficiencies of the ORC and analyzed correlation between volumetric efficiencies of the expander and thermal efficiencies of the ORC.

• Journal of the Korean Institute of Gas
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• v.20 no.5
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• pp.50-56
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• 2016

In this work, the open-drive oil free air compressor is modified to activate an organic Rankine cycle system as an expanding machine. The shape of the modified scroll expander case is a rectangular parallelepiped and the size of the case is $0.0394m^3$. The scroll expander is operated in an ORC using R245fa as working fluid with various working conditions for the performance test. The test data points are used to calculate the parameters of the scroll expander semi-empirical simulation model. The simulation results are compared with the experimental results to validate the simulation model.

• East Asian mathematical journal
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• v.40 no.3
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• pp.287-293
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• 2024

For a nondegenerate irreducible projective variety, it is a classical problem to describe its defining equations and the syzygies among them. In this paper, we precisely determine a minimal generating set and the minimal free resolution of defining ideals of some rational curves of maximal genus in ℙ³.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.10
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• pp.919-926
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• 2013

Experiments were conducted to determine the operating characteristics of a small-scale ORC (organic Rankine cycle) system for various low-temperature heat sources. A small-scale ORC power generation system adopting R-245fa as a working fluid was designed and manufactured. Hot water was used as the heat source, and the temperature was controlled using 110-kW electric resistance heaters that provided temperatures of up to $150^{\circ}C$. An open-drive oil-free scroll expander directly connected to a synchronous generator was installed in the ORC unit. Experiments were conducted by varying the rotational speed of the expander under the same heat source temperature conditions. The factors that influence the performance of the small-scale ORC system were analyzed and discussed.