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Dubrovnik, Croatia

Cho S.-Y.,Gyeongsang National University | Cho C.-H.,Suntech Co. | Choi S.-K.,Korea Institute of Machinery and Materials
Energy | Year: 2015

The ORC (organic Rankine cycle) has been used to generate electrical or mechanical power from low-grade thermal energy. However, even though many kinds of such energy are available, this thermal energy is typically not available continuously at a constant level. In order to utilize fluctuating thermal energy optimally, an axial-type turbine was applied to the expander, and two nozzles were used to control the mass flow rate. The tip diameter of the rotor was 80mm and the nozzle was designed as a supersonic nozzle to increase the turbine output power. Experiments were conducted at various TIT (turbine inlet temperatures) with the partial admission rate of 16.7%. The experimental results were compared with the predicted results of the cycle analysis. In the cycle analysis, the output power of the ORC was predicted considering the load dissipating the output power produced by the ORC, as well as the turbine efficiency. The predicted results showed the same trend as the experimental results, and the experimental results showed that the system efficiency of 2% was obtained at the TIT of 100°C. Hence, this type of turbine can be applied to produce a wide range of power continuously where the available thermal energy varies. © 2015 Elsevier Ltd.

Cho S.-Y.,Gyeongsang National University | Cho C.-H.,Suntech Co. | Ahn K.-Y.,Korea Institute of Machinery and Materials | Lee Y.D.,Korea Institute of Machinery and Materials
Energy | Year: 2014

The organic Rankine cycle is widely used to obtain electric power from renewable energy sources, such as solar energy, geothermal energy, and waste thermal energy. In a typical ORC, a turbo-expander or volumetric expander is applied to convert the thermal energy to mechanical energy. The turbo-expander is widely used for large-scale output power because it has merits when used with large mass flowrates; the scroll expander is used for small-scale output power. In ORCs that produce small-scale output power, the available thermal energy as a renewable heat source usually cannot be supplied continuously. For fluctuating levels of available thermal energy, positive displacement machine has difficulty in adjusting the mass flowrate. In order to regulate the mass flowrate for varying thermal energies, a small-scale radial-type turbine and supersonic nozzles were designed specifically for this study. R245fa was used as the working fluid, and the thermodynamic properties of the working fluid in the cycle were predicted on the basis of the designed turbine blade and nozzle shape even though the mass flowrates were varied. The output powers at the off-design operations were predicted for the full range of 30kW according to the number of nozzles used. © 2013 Elsevier Ltd.

Suntech Co. | Date: 2015-02-19

Methods of manufacturing polymeric stents by forming a pattern on a polylactic acid tube using a second harmonic generator laser and polylactic acid polymeric stents having a pattern formed using a second harmonic generator laser.

Suntech Co. | Date: 2013-09-05

A sheath and cerclage thread for mitral cerclage annuloplasty, where the cerclage thread is inserted into a lumen created independently from the lumen through which the guide wire is passed.

A bioabsorbable blend comprising poly(L-lactide) (PLLA) and a phosphorylcholine group-containing copolymer (PPCP) capable of enduring the mechanical strength of blood vessel walls and applicable for fabricating cardiovascular devices was developed. The blend acts as a scaffold to support blood vessel walls during vascular healing and undergoes biodegradation in vivo after vascular healing is complete. Furthermore, the blend can prevent the formation and adsorption of thrombi.

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