Study and optimization of a solar subcritical organic Rankine cycle

Marion, Michaël; Voicu, Ionuț; Tiffonnet, Anne-Lise

doi:10.1016/j.renene.2012.04.047

Cited by 57 publications

(16 citation statements)

References 14 publications

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“…Although there have been many studies concerning the effect of a number of system parameters on the ORC system performance [2,5,9,[13][14][15][16][17][18], a detailed analysis of the effect of the heat source conditions on the heat transfer characteristics and system performance has rarely been performed. In this work, an analysis study of the heat transfer characteristics and system performance of a 250 kW ORC system at off-design heat source flow rates was conducted by the pressure control approach, i.e., changing the evaporating pressure to meet the particular system requirements when the heat source flow rate varies from the design value.…”

Section: Introductionmentioning

confidence: 99%

Performance of a 250 kW Organic Rankine Cycle System for Off-Design Heat Source Conditions

Liu

2014

Proceedings of 1st International E-Conference on Energies

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An organic Rankine cycle system with a preheater, evaporator, condenser, turbine, generator, and pump was used to study its off-design performance and operational control strategy. R245fa was used as a working fluid. The net power output is 243 kW and the system thermal efficiency is 9.5% under the design conditions. For an off-design heat source flow rate (m W ), the operating pressure was controlled to meet the condition that the R245fa reached the saturation liquid and vapor states at the outlet of the preheater and evaporator, respectively. The analytical results demonstrated that the operating pressure increased with increasing m W ; a higher m W yielded better heat transfer performance of the preheater and required a smaller evaporator heat capacity; and the net power output and system thermal efficiency increased with increasing m W . The net power output increased by 64.0% while the total heat transfer rate increased by only 9.2% for the studied range of m W . To conclude, an off-design operation is studied for a heat source flow rate which varied from -39.0% to +78.0% from the designed rate, resulting in -29.2% to +16.0% and -25.3% to +12.6% variations in the net power output and system thermal efficiency, respectively.

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Section: Introductionmentioning

confidence: 99%

Performance of a 250 kW Organic Rankine Cycle System for Off-Design Heat Source Conditions

Liu

2014

Proceedings of 1st International E-Conference on Energies

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“…The authors found that the low temperature evacuated tube collectors using cyclohexane, isopentane, benzene, and R245ca as the working fluid provided the lowest solar collector areas necessary. Marion et al [33] developed a theoretical model based on heat balance equations for a flat plate solar collector in line with an ORC and validated their proposed model with experimental results. They also performed a parametric study to optimize the system configuration and showed that the optimized configuration can produce net mechanical power with an efficiency up to 11%.…”

Section: Introductionmentioning

confidence: 99%

Performance Evaluation of a Solar-Powered Regenerative Organic Rankine Cycle in Different Climate Conditions

2017

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Abstract:A model to evaluate the performance of a solar powered regenerative Organic Rankine Cycle (R-ORC) using five dry organic fluids: RC318, R227ea, R236ea, R236fa, and R218, is presented in this paper. The system is evaluated in two locations in the U.S.: Jackson, MS and Tucson, AZ. The weather data for each location is used to determine the heat available from the solar collector that could be used by the R-ORC to generate power. Results from the R-ORC performance are compared with a basic ORC using first and second law criteria as well as primary energy consumption (PEC) and carbon dioxide emission (CDE) savings for both locations. An economic analysis to determine the maximum capital cost for a desired payback period is presented in this paper. A parametric analysis is also performed to study the effect of the turbine efficiency as well as the open feed organic fluid heater intermediate pressure on the system performance. Results indicate that the R-ORC is able to generate more power than the basic ORC for some of the selected working fluids. For the R-ORC, R236ea is the working fluid that show the best performance among the evaluated fluids under the modeled conditions. On the other hand, the basic ORC with R236ea as the working fluid outperformed three of the fluids in the R-ORC. Also, the R-ORC evaluated in Tucson, AZ is able to generate more power, to provide more PEC and CDE savings, and had a higher available capital cost than the R-ORC evaluated in in Jackson, MS.

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“…In their study, twelve thermofluids including hydrocarbons (HCs), Hydrofluorocarbons (HFCs) and ammonia were analyzed. A theoretical and experimental analysis of a solar ORC with FPC using HFC-134a, HFC-227ea and HFC-365mfc was performed by [19]. The results showed that HFC-365mfc was the most efficient fluid.…”

Section: Introductionmentioning

confidence: 99%

A Theoretical and Experimental Study of HFE-7000 in a Small Scale Solar Organic Rankine Cycle As a Thermofluid

Helvaci

Khan

2017

Volume 2: I&C, Digital Controls, and Influence of Human Factors; Plant Construction Issues and Supply Chain Management; Pla

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Renewable energy technologies and sources have been playing a key role in reducing reliance on fossil fuels and significantly reducing CO 2 emissions and its footprint. EU initiative of generating 50% of the energy needs through sustainable sources by 2050 needs a direct response in terms of providing applied solutions to realize this target on time. Solar energy is one of the major and abundantly renewable energy sources which are free and clean. Solar energy can be utilized by means of solar Photovoltaic (PV) or solar collectors. Concentrating solar collectors supply thermal energy from medium to high grade where as non-concentrating collectors (flat plate) delivers low-grade thermal energy. The use of thermofluids with boiling temperatures lower than the water, allows the operation of low grade solar thermal systems on an Organic Rankine Cycle (ORC) to generate both mechanical and heat energy. At the same time, the selection of appropriate thermofluid is an important process and has a significant effect both on the system performance and the environment. Conventional thermofluids such as Chlorofluorocarbons (CFCs) and Hydrochlorofluorocarbons (HCFCs) have high ozone depletion (ODP) and high global warming (GWP) potential. It is therefore important to investigate novel and environmentally friendly thermofluids to address environmental impacts as global warming and ozone layer depletion. Hydrofluoroethers (HFEs) are non-ozone depleting substances and they have relatively low GWP. Therefore, HFEs can be used as a replacement for CFCs and HCFCs. In this study, a solar ORC is designed and commissioned to use HFE 7000 as a thermofluid. The proposed system consists of a flat-plate solar collector, a vane expander, a condenser and a pump where the collector and the expander are used as the heat source and prime mover of the cycle respectively. The performance of the system is determined through energy analysis. Then, a mathematical model of the cycle is developed to perform the simulations using HFE-7000 at various expander pressure. Experimental data indicated that the efficiency and the net mechanical work output of the cycle was found to be 3.81% and 135.96 W respectively. The simulation results showed that increasing the pressure ratio of the cycle decreased the amount of the heat that is transferred to HFE 7000 in the collector due to the increased heat loss from the collector to the environment. Furthermore, net output of the system followed a linear augmentation as the pressure ratio of the system increased. In conclusion, both the experimental and theoretical research indicates that HFE 7000 offers a viable alternative to be used efficiently in small scale solar ORCs to generate mechanical and heat energy.

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Study and optimization of a solar subcritical organic Rankine cycle

Cited by 57 publications

References 14 publications

Performance of a 250 kW Organic Rankine Cycle System for Off-Design Heat Source Conditions

Performance of a 250 kW Organic Rankine Cycle System for Off-Design Heat Source Conditions

Performance Evaluation of a Solar-Powered Regenerative Organic Rankine Cycle in Different Climate Conditions

A Theoretical and Experimental Study of HFE-7000 in a Small Scale Solar Organic Rankine Cycle As a Thermofluid

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