Study of zeotropic mixtures of ORC (organic Rankine cycle) under engine various operating conditions

Yang, Ke; Zhang, Hongguang; Wang, Zhen; Zhang, Jian; Yang, Fubin; Wang, Enhua; Yao, Baofeng

doi:10.1016/j.energy.2013.04.074

Cited by 83 publications

(36 citation statements)

References 35 publications

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“…Finally, the working fluid enters the evaporator (stream m′) to carry out the next cycle. For the working fluid in the ORC, R245fa is selected as the working fluids, due to its good thermodynamic performance and small negative impact on the environment [23,24].…”

Section: System Descriptionmentioning

confidence: 99%

Thermo-Economic Comparison and Parametric Optimizations among Two Compressed Air Energy Storage System Based on Kalina Cycle and ORC

Wang

Yao

et al. 2016

Energies

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Abstract:The compressed air energy storage (CAES) system, considered as one method for peaking shaving and load-levelling of the electricity system, has excellent characteristics of energy storage and utilization. However, due to the waste heat existing in compressed air during the charge stage and exhaust gas during the discharge stage, the efficient operation of the conventional CAES system has been greatly restricted. The Kalina cycle (KC) and organic Rankine cycle (ORC) have been proven to be two worthwhile technologies to fulfill the different residual heat recovery for energy systems. To capture and reuse the waste heat from the CAES system, two systems (the CAES system combined with KC and ORC, respectively) are proposed in this paper. The sensitivity analysis shows the effect of the compression ratio and the temperature of the exhaust on the system performance: the KC-CAES system can achieve more efficient operation than the ORC-CAES system under the same temperature of exhaust gas; meanwhile, the larger compression ratio can lead to the higher efficiency for the KC-CAES system than that of ORC-CAES with the constant temperature of the exhaust gas. In addition, the evolutionary multi-objective algorithm is conducted between the thermodynamic and economic performances to find the optimal parameters of the two systems. The optimum results indicate that the solutions with an exergy efficiency of around 59.74% and 53.56% are promising for KC-CAES and ORC-CAES system practical designs, respectively.

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Section: System Descriptionmentioning

confidence: 99%

Thermo-Economic Comparison and Parametric Optimizations among Two Compressed Air Energy Storage System Based on Kalina Cycle and ORC

Wang

Yao

et al. 2016

Energies

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“…ORC systems that use mixed working fluids may have better running performances than pure working fluids [24][25]. Mixed working fluids have drawn the attention of several scholars [26][27]. The change in the mass fraction of components in mixed working fluids can cause changes in the properties of mixed working fluids, such as critical temperature, critical pressure, and slip temperature.…”

Section: Introductionmentioning

confidence: 99%

Study on Mixed Working Fluids with Different Compositions in Organic Rankine Cycle (ORC) Systems for Vehicle Diesel Engines

Yang

Zhang

Wang

et al. 2014

Entropy

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Abstract:One way to increase the thermal efficiency of vehicle diesel engines is to recover waste heat by using an organic Rankine cycle (ORC) system. Tests were conducted to study the running performances of diesel engines in the whole operating range. The law of variation of the exhaust energy rate under various engine operating conditions was also analyzed. A diesel engine-ORC combined system was designed, and relevant evaluation indexes proposed. The variation of the running performances of the combined system under various engine operating conditions was investigated. R245fa and R152a were selected as the components of the mixed working fluid. Thereafter, six kinds of mixed working fluids with different compositions were presented. The effects of mixed working fluids with different compositions on the running performances of the combined system were revealed. Results show that the running performances of the combined system can be improved effectively when mass fraction R152a in the mixed working fluid is high and the engine operates with high power. For the mixed working fluid M1 (R245fa/R152a, 0.1/0.9, by mass fraction), the net power output of the combined system reaches the maximum of 34.61 kW. Output energy density of working fluid (OEDWF), waste heat recovery OPEN ACCESSEntropy 2014, 16 4770 efficiency (WHRE), and engine thermal efficiency increasing ratio (ETEIR) all reach their maximum values at 42.7 kJ/kg, 10.90%, and 11.29%, respectively.

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“…It's known that the Rankine cycle is a typical heat recovery system which is widely used in the industry, such as the cogeneration system [12][13][14]. For a low-temperature heat resource like PEMFC, the organic fluids are suitable to be applied [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Waste Heat Recovery of a PEMFC System by Using Organic Rankine Cycle

Shi

Peng

et al. 2016

Energies

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Abstract:In this study, two systems are brought forward to recover the waste heat of a proton exchange membrane fuel cell (PEMFC), which are named the organic Rankine cycle (ORC), and heat pump (HP) combined organic Rankine cycle (HPORC). The performances of both systems are simulated on the platform of MATLAB with R123, R245fa, R134a, water, and ethanol being selected as the working fluid, respectively. The results show that, for PEMFC where operating temperature is constantly kept at 60˝C, there exists an optimum working temperature for each fluid in ORC and HPORC. In ORC, the maximal net power can be achieved with R245fa being selected as the working fluid. The corresponding thermal efficiency of the recovery system is 4.03%. In HPORC, the maximal net power can be achieved with water being selected in HP and R123 in ORC. The thermal efficiency of the recovery system increases to 4.73%. Moreover, the possibility of using ORC as the cooling system of PEMFC is also studied. The heat released from PEMFC stack is assumed to be wholly recovered by the ORC or HPORC system. The results indicate that the HPORC system is much more feasible for the cooling system of a PEMFC stack, since the heat recovery ability can be promoted due to the presence of HP.

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Study of zeotropic mixtures of ORC (organic Rankine cycle) under engine various operating conditions

Cited by 83 publications

References 35 publications

Thermo-Economic Comparison and Parametric Optimizations among Two Compressed Air Energy Storage System Based on Kalina Cycle and ORC

Thermo-Economic Comparison and Parametric Optimizations among Two Compressed Air Energy Storage System Based on Kalina Cycle and ORC

Study on Mixed Working Fluids with Different Compositions in Organic Rankine Cycle (ORC) Systems for Vehicle Diesel Engines

Waste Heat Recovery of a PEMFC System by Using Organic Rankine Cycle

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