The Study Of Low-temperature Power Generation Based On Solar Organic Rankine Cycle

Organic Rankine cycle (ORC) is a Rankine cycle, where an organic fluid is used instead of water as the working fluid. ORCs have been investigated for power production by promoting turbine work. Solar,geothermal resources,ocean thermal energy,industrial waste heat and biomass energy,are by far the most commonly available resource in organic Rankine cycle. In this paper, thermodynamic model of orginic Rankine cycle is established by using solar as heat sourse,and thermal performance of orginic Rankine cycle system is researched.It is shown that the character of the working fliud has a significant effect on the performance of solar organic Rankine cycle system, R600, R600a, R245fa, R236fa, R236ea, R601, R601a, RC318, R227ea are choosed as the working fluids by comprehensive consideration. the cycle performances of the low-temperature solar Rankine cycle system were studied based on the first law of thermodynamics and the second law of thermodynamics. The evaporating temperature, thermal efficiency, vapor consumption rate, work rate and exergy efficiency of the cycle system were shown. Form the first law of thermodynamics,it is known that the evaporating temperature and thermal efficiency increases as the evaporating temperature increases,and power output ratio and specific steam consumption is decreases as the evaporating temperature increases. Form the second law of thermodynamics,there is a maximum exergy efficiency and minimum irreversibility as the evaporating temperature increases,above all,R245fa was recommended as the proper fluid in solar organic Rankine cycle system. The turbine output temperature and pressure has a significant effect on the performance of solar organic Rankine cycle system, the impact of this two factors on the system performance is investigated and calculated. the thermodynamics analysis reveals the relationship between these two parameters and cycle performances,primarily covering system thermal effciency,net output power and system irreversibility.lt is shown that it exsists best input pressure and temperature when irreversibility of system is lowest. Based on matlab interface, the paper uses genetic algorithm to calculate parameter optimization in the system. By genetic operations,the proper input pressure and temperature anr obtained,and under the conditon of the lowest irreversibility, detail thermal performance parameters in the system are calculated.