• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.5
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• pp.647-655
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• 2021

The IMO (International Maritime Organization) is discussing the improvement of energy ef iciency of ships in order to reduce greenhouse gas emissions from ships. Currently, by applying an ORC power generation system using waste heat generated from ships, high energy conversion efficiency can be expected from ships. This technology uses an organic medium based on Freon or hydrocarbons as the working fluid, which evaporates at a lower temperature range than water. Through this, it is possible to generate steam (gas) and generate power at a low and low temperature relatively. In this study, the analysis of heat flow between the refrigerant and waste heat in the ORC power generation system, which is an organic Rankine cycle, is analyzed using 3D simulation techniques to determine the temperature change, velocity change, pressure change, and mass change of the fluid flowing of the WHRU (Waste Heat Recovery Unit) inside and the outside the structure. The purpose of this study is to analyze how the mass change affects the structure, and this study analyzed the heat transfer of the heat exchanger from the refrigerant and the exhaust gas of the ship's main engine in the ORC power generation system using this technique.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.4
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• pp.383-390
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• 2010

In this study, a thermoelectric power generation system was constructed for a waste-heat recovery. Thermoelectric modules were attached to a stainless steel duct, and a hot air blower was set such that it faced the duct inlet. We found that to achieve the maximum power out of the system, the temperature in the hot side of the thermoelectric module should be uniform. The optimum compressive pressure exerted on the module was observed. Further, the thermoelectric power performance was evaluated using the heat sink attached to the cold side of the thermoelectric module. In particular, when using a natural-convection heat sink, the power output difference is approximately five times.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.1
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• pp.51-56
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• 2012

This paper reports the generation efficiency and the thermal performance of a thermoelectric generator (TEG) harvesting energy from the waste heat of high power electronic components. A thermoelectric (TE) model containing thermal boundary resistances is used to predict generation efficiency and junction temperature of a high power electronic component. The predicted results are verified with measured values, and the discrepancy between prediction and measurement is seen to be moderate. The verified TE model predicts generation efficiencies, junction temperatures of the component, and temperature differences across a TEG at various source heat flows associated with various electrical load resistances. This study explores effects of the load resistance on the generation efficiency, the temperature difference across a TEG, and the junction temperature.

• Journal of Power System Engineering
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• v.20 no.2
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• pp.17-25
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• 2016

In this paper, the feasibility study on a gerotor type expander as a power converting device in a small scale power generation ORC system was made by performance analysis of the gerotor expander. Design of a 1kW-class gerotor expander was carried out and its performance was numerically simulated. For a R134a Rankine system with about 20 kW solar heat source, the gerotor expander efficiency was calculated to be 35~75% for the operating conditions of $Te=80{\sim}100^{\circ}C$ and $Tc=30{\sim}60^{\circ}C$. Maximum expander efficiency was obtained at an expansion ratio somewhat higher than the design expansion ratio due to pre-expansion during suction process inside the outer and inner rotor mate. If the operating expansion ratio is not far from the design expansion ratio, the gerotor expander performance can be well compared to that of a scroll type.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.5
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• pp.595-602
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• 2012

In this study, for the purpose of reduction of $CO_2$ gas emission and to increase recovery of waste heat from ships, the ORC (Organic Rankine Cycle) is investigated and offered for the conversion of temperature heat to electricity from waste heat energy from ships. Simulation was performed with waste heat from the exhaust gasse which is relatively high temperature and cooling sea water which is relatively low temperature from ships. Various fluid is used for simulation of the ORC system with variable temperature and flow condition and efficiency of system and output power is compared. Finally, 2,400kW output power is obtained by system optimization of the preheater and reheater utilizing waste heat form sea water cooling system.

• Journal of Energy Engineering
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• v.27 no.4
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• pp.50-63
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• 2018

The issue of global warming and environmental pollutant has become an international concern due to the widespread use of fossil fuels, and thus waste heat recovery technologies has become important to improve energy utilization. The global market of power generation system using industrial waste heat is rapidly growing at an average rate of 5% due to its advantage of increasing energy efficiency. In order to design an optimal waste heat recovery system, it is necessary to develop a program that offers economic evaluation of each power generating technology according to the heat source conditions. In this paper, the economic analysis module to calculate LCOE is developed and verified the reliability against NETL economic analysis results. As a result of the verification, the error rate is about 6 ~ 7%, which satisfy the accuracy for business feasibility evaluation. In order to enhance the reliability, the module was improved by applying the levelization method used by NETL. As a result of the verification of reliability, the error rate is less than 1% and the accuracy is improved.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.776-781
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• 2001

To enhance thermal efficiency of thermal facility through recovery of low and medium temperature waste heat, 1MW organic Rankine cycle system was designed and developed. The exhaust gases of $175^{\circ}C$ at two 100MW power plants in pohang steel works were selected as the representative of low and medium temperature waste heat in industrial process for the heat source of the organic Rankine cycle system. HCFC-123, a kind of harmless refrigerant, was chosen as the working fluid for Rankine cycle. The organic Rankine cycle system with selected exhaust gases and working fluid was designed and constructed. From the operation, it was confirmed that the organic Rankine cycle system is available for low and medium temperature waste heat recovery in industrial process. The optimum operating manuals, such as heat-up of hot water, turbine start-up, and the process of electric power generation, were derived. However, electric power generated was not 1MW as designed but only 670kW. It is due to deficiency of pump capacity for supply of HCFC-123. So it is necessary to increase the pump capacity or to decrease the pressure loss in pipe for more improved HCFC-123 supply.

• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.372-378
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• 2012

This study was carried out in order to determine the optimum length of a roll type PE pipe heat exchanger employed in the water-to-water heat pump system using the waste heat of the heated effluent flowed out from thermal power generation plants as a heat source. And the heat pump system of 30 RT for an experimental test was designed and manufactured. And also PE pipes were employed to recover the waste heat from the heated effluent. The inside diameter of PE pipe heat exchanger was 20 mm, the thickness was 2 mm and the diameter of a roll was 1,000 mm. And from the results of this study, we found that the optimum length of PE pipe heat exchanger was 75 m per the heat pump capacity of 1.0 RT (3.51 kW) and then the heating COP of heat pump system was 3.8.

• Journal of Navigation and Port Research
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• v.36 no.5
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• pp.349-355
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• 2012

In this study, for the purpose of reduction of $CO_2$ gas emission and to increase recovery of waste heat from ships, the ORC(Organic Rankine Cycle) is investigated and offered for the conversion of temperature heat to electricity from waste heat energy from ships. Simulation is performed with waste heat from the exhaust gasse which is relatively high temperature and cooling sea water which is relatively low temperature from ships. The result shows that 1,000kW power generation is available from exhaust gas and 600kW power generation is available from sea water cooling system. Different fluid is used for simulation of the ORC system with variable temperature and flow condition and efficiency of system and output power is compared.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.626-629
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• 2008

In this study, a geothermal power generation system using the Kalina cycle was investigated by the simulation method. The Kalina cycle system can be used for the utilization of a low-temperature heat sources such as geothermal and industrial waste heat that are not hot enough to produce steam. The sea/river water can be considered as a cooling media. A steady-state simulation model was developed to analyze and optimize its performance. The model contains a turbine, a pump, an expansion valve and heat exchangers. The turbine and pump were modelled by an isentropic efficiency, while a condenser, an evaporator and a regenerative heat exchanger were modeled by UA-LMTD method with a counter-flow assumption. The effect of the ammonia fraction at the separator inlet on the cycle performance is investigated in detail.