• 유공압시스템학회:학술대회논문집
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• 유공압시스템학회 2010년도 춘계학술대회
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• pp.116-125
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• 2010

In this study, a novel hydraulic energy-regenerative system was presented from its proposal through its modeling to its control. The system was based on a closed-loop hydrostatic transmission and used a hydraulic accumulator as the energy storage system in a novel configuration to recover the kinetic energy without any reversion of the fluid flow. The displacement variation in the secondary unit was reduced, which widened the uses of several types of hydraulic pump/motors for the secondary unit. The proposed system was modeled based on its physical attributes. Simulation and experiments were performed to evaluate the validity of the employed mathematical model and the energy recovery potential of the system. The experimental results indicated that the round trip recovery efficiency varied from 22% to 59% for the test bench.

• Journal of Advanced Marine Engineering and Technology
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• 제38권1호
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• pp.8-14
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• 2014

본 연구에서는 R-245fa를 작동유체로 하는 250kW급의 선박폐열회수 발전 시스템을 설계하고 과열기의 구성에 따른 사이클 특성을 연구 하였다. 과열기와 증발기의 직렬연결과 병렬연결의 2가지 조건을 시뮬레이션 하였다. 과열기와 증발기의 직렬연결 시뮬레이션에서는 작동유체 과열에 따른 엔탈피 증가로 4.7%의 출력상승을 얻을 수 있었고, 목표출력을 250kW로 정하였을 경우에는 사이클유량을 4.1% 감소시킬 수 있었다. 과열기와 증발기의 병렬연결 시뮬레이션에서는 사이클의 목표출력을 250kW로 정하였을 경우에 과열기로 가는 열원유체의 유량이 증가함에 따라 사이클 유량이 감소하여 작동유체펌프의 소요동력이 최대 7.9% 감소 하였으며, 유량비율에 따른 사이클효율과 정미효율은 큰 변화가 없었다.

• 설비공학논문집
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• 제24권12호
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• pp.875-880
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• 2012

The field of the large volume heat exchanger for wasted heat recovery ventilation system is being expanded enormously seeing as the fact that the quantity of reducing energies are huge due to the large volume heat exchanger for wasted heat recovery system at large buildings and factories, which consume large amount of energies while it has been arising huge amount of losses in Korea because of the lack of technology. To develop large volume waste heat recovery heat exchanger, rotor type heat exchanger was simulated for the surface corrugation. Based on the simulation results produced $30,000m^3/h$ grade waste heat recovery, heat exchanger was performed for the actual experiment. In addition, performance tests exceed the capacity of a large waste heat recovery heat exchanger performance test methods proposed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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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.

• 신재생에너지
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• 제18권2호
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• pp.82-89
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• 2022

In this study, the exergy characteristics were analyzed, according to the mass flow rate of the propane working fluid and the pressure change in the turbine inlet, for the efficient recovery of cold energy and exhaust heat by the waste energy recovery system applied to the LNG FSRU regasification process. When the turbine inlet pressure and mass flow rate of the Primary Rankine Cycle were kept constant, the exergy efficiency and the net power increased. This occurred as the turbine inlet pressure and the mass flow rate of the working fluid increased in the Secondary Rankine Cycle, respectively, and the maximum values were confirmed. In this regard, the fluctuations in the exergy rate flowing into and out of the system and the exergy rate destroyed by pumps, evaporators, turbines, and LNG heat exchangers (condensers) were examined in detail.

• 한국수소및신에너지학회논문집
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• 제21권6호
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• pp.570-579
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• 2010

Since the temperature of waste heat source is relatively low, it is difficult to maintain high level of efficiency in power generation when the waste heat recovery is employed in the system. In an effort to improve the thermal efficiency and power output, use of ammonia-water mixture as a working fluid in the power cycle becomes a viable option. In this work, the performance of ammonia-water mixture based Rankine cycle is thoroughly investigated in order to maximize the power generation from the low temperature waste heat. In analyzing the power cycle, several key system parameters such as mass fraction of ammonia in the mixture and turbine inlet pressure are studied to examine their effects on the system performance. The results of the cycle analysis find a substantial increase both in power output and thermal efficiency if the fraction of ammonia increases in the working fluid.

• 한국산업융합학회 논문집
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• 제5권3호
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• pp.165-171
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• 2002

The thermosyphon has been used as a heat transmission device in the heat recovery of low level energy and cooling for heat generating equipments. Many studies on the working fluids and wicks have been reported to improve the heat transfer efficiency of the thermosyphon. A low temperature heat pipe with acetone is chosen in the present study to compare the heat transfer characteristics due to pouring amount of working fluid, magnitude of power supplied and tilt angles. The thermosyphon made ⵁ$15.88{\times}0.8t{\times}600mm$ of copper, evaporation section 200mm, insulation section 25mm, condensation 375mm. Heat transfer rate of the thermosyphon increase as magnitude of power supplied increase and observe dry out phenomenon at 5~10% of pouring amount of working fluid. So thermosyphon at the 150kJ/s judged to need 12% or more. Heat transfer rate of the thermosyphon have nothing to do with tilt angles. Dry out phenomenon of the thermo syphon makes it possible that a low temperature thermosyphon may be used to control temperature and heat transfer of a system when the critical quantity of a working fluid is supplied in the thermosyphon.

• 한국유체기계학회 논문집
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• 제15권3호
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• pp.57-63
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• 2012

Effects of coolant pre-cooling and fuel pre-heating on the performance of a combined cycle using a F-class gas turbine were investigated. Coolant pre-cooling results in an increase of power output but a decrease in efficiency. Performance variation due to the fuel pre-heating depends on the location of the heat source for the pre-heating in the bottoming cycle (heat recovery steam generator). It was demonstrated that a careful selection of the heat source location would enhance efficiency with a minimal power penalty. The effect of combining the coolant pre-cooling and fuel pre-heating was also investigated. It was found that a favorable combination would yield power augmentation, while efficiency remains close to the reference value.

• 청정기술
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• 제11권1호
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• pp.13-19
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• 2005

에너지 회수를 위한 변형 흡수 열펌프 연구를 메탄올-글리세린을 이용하여 수행하였다. 이 물질의 열역학 데이터를 이용하여 변형 흡수 열펌프의 이론적 열효율 값을 각 기관의 조업 조건에 따라서 계산하였다. $70-80^{\circ}C$의 산업 폐열 온도를 가지고 $40-50^{\circ}C$ 승온 시킬 때 열효율 값 0.4이상을 얻을 수 있었다.

• 한국유체기계학회 논문집
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• 제12권1호
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• pp.43-50
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• 2009

Waste heat recovery process designs and performance analyses are conducted on the IGCC(Integrated Gasification Combined Cycle) power plants integrated with two different coal gasification and gas cleanup processes by Shell and GE/Texaco. Through the analysis results, the present study provides the steam integration concept between the HRSG and the chemical processes of IGCC power plant, and investigates the effect of steam integration on the power generation of IGCC power plant. The present simulation results show less steam power output and higher overall IGCC efficiency of the Shell-based power plant than the GE/Texaco.