Papers by Keyword: Organic Rankine Cycle (ORC)

Abstract: The research intends to investigate the energetic performances of Organic Rankine Cycles (ORCs) for the exploitation of the biomass resulting from agricultural residues. To this purpose, a parametric analysis has been carried out. Saturated and superheated conditions at the turbine inlet have been imposed and the effect of the internal regeneration on plant performances has been studied. The results highlight that ORC plants represent an interesting and sustainable solution for small-scale and decentralised power production. Moreover, the analysis shows the significant impact of the temperature and internal regeneration technique on the performances of the biomass power plants.

Abstract: In the current paper, under the condition of different flue gas temperatures and constant flue gas thermal power, the influence of different organic working fluids on the efficiency of sub-critical organic Rankine cycle system were studied. The efficiency and other parameters of the simple system were calculated. The results show that the efficiency of sub-critical organic Rankine cycle system could reach maximum when the parameters of the working fluids in the expander inlet are dry-saturation. Flammability, toxicity, ozone depletion and other factors of the working fluids should be considered in the organic Rankine cycles. R245fa is considered a better choice for low-temperature heat source power generation, and the efficiency of the system is about 10.2%; for the high-temperature heat source, R601a can be considered; however, due to its high flammability, novel working fluids should be further discovered for power generation.

Abstract: Organic Rankine Cycle (ORC) has attracted much attention in recent years, since it has potential of reducing fossil fuel consumption and many favorable characteristics to exploit low-grade energy sources. This work carries out an exergetical performance assessment of ORC with superheating comparatively for various organic fluids. Special attention is paid to the effect of evaporating temperature on the exergy destructions (anergies) at various system components and the exergy efficiency of system. Results show that for a given source both the anergies at the components and exergy efficiency may have a peak value or monotonically increase with evaporating temperature.

Abstract: The evaporator is a critical component when using organic Rankine cycle (ORC) to recover waste heat from an internal combustion engine. Evaluating the amount of heat quantity that can be transferred in a designed evaporator is very important for a successful ORC system. In this paper, a finned tube evaporator used for recovering the exhaust waste heat of a diesel engine was presented. The mathematical model for the evaporator was set up according to the dimensions of the designed evaporator along with the specified working conditions of ORC. The evaporator performance was analyzed as the matched diesel engine operating at the rated power point. The results indicate that the heat transfer quantity of the designed evaporator can be reached at 76 kW, and the exhaust temperature at the evaporator exit can be reduced to 115°C.

Abstract: Rankine cycles using organic working fluids are widely believed feasible in recovering low enthalpy-containing heat. Through the analysis, the enthalpy difference, the dryness of inlet wet steam and evaporating and condensing temperature have significant influence on the energy conversion efficiency. The power output also relies on the specific volume and latent heat, which determine the mass flow rate. The results serve good guideline for experiments and systematic optimization.

Abstract: A Rankine cycle using organic fluids as working fluids, called organic Rankine cycle (ORC), is potentially feasible in recovering low enthalpy containing heat sources. The choices of fluids should meet the requirement of environment, safety, critical pressure and critical temperature etc. Under the proposed working conditions, R600a, R245fa, R236fa, R236ea, R227ea are chosen as the working fluids of the low-temperature Rankine cycle system, then those fluids are investigated and compared from cycle efficiency, work ratio, exergy efficiency, irreversible loss. The results show that R245fa is an available and effective working fluid for low-temperature Rankine cycle.

Abstract: Organic Rankine Cycle (ORC) is dramatically suitable for low temperature waste-heat generation. The small-scale radial inflow turbine is introduced to integrate into the ORC characterized by simple structure, low parts count, high efficiency, especially getting high efficiency under the condition of smaller flow. This turbine is comprised of four main parts named by the volute, the nozzle (stator), the impeller (rotor), and the diffuser respectively. This paper introduces how to design and model the parts in detail, discusses modeling skills and shares experience. The structure of the volute and impeller is so complicated that parts are not easy to model. These 3D models can directly import to both ANSYS and FLUENT to analysis the flow field in order to achieve the optimize parameters.

Abstract: As for the industrial exhaust heat with the temperature ranging from 120°C to 200°C, 5 working fluids commonly used in organic Rankine cycle, namely R113、R123、R134a、R245fa and R600a, have been analysed from the perspective of safety, environment and economical efficiency. The results show that: R123 is of great poison, but its thermal economical efficiency is the best, especially under the condition of high temperature. The suitable ambient temperature ranges from 20-35°C. R245fa belongs to a safe and environment friendly fluid. For its best comprehensive property and wide range of ambient temperature, R245fa is very beneficial to the ORC system.

Abstract: In this paper, a schematic of such installation is presented here with a description of its operation and the algorithm of calculations of a supercritical waste heat plant. An analysis of the influence of a kind of working fluid on the effectiveness of operation of a plant was carried out. The obtained results enabled the unanimous conclusion that the application of supercritical conditions in low-temperature organic Rankine cycle (ORC) installations of waste heat plants allows significantly higher values of both efficiency and power to be achieved.

Abstract: This study presents an energetic performance analysis for a waste heat produces electrical power system which is use organic Rankine cycle (ORC) from steelworks. In order to simulate the system under steady-state conditions, a mathematical model is developed. The developed model is used to determine the potential effects caused by the changes of the design parameters on the energetic performance of the system. As design parameters, turbine inlet pressure, condenser temperature, are taken into account. In this regard, the electrical power is estimated by parametrical analysis and discussed comprehensively.