Analysis Of Power Generation System Based On Organic Rankine Cycles Driven By Low-grade Heat

Due to the low cycle efficiency,complicated system and limited economic benefits, recycling the wide range and huge quantities of low-temperature heat in traditional way based on Rankine cycles with water as working fluid, is not appropriate. While utilize organic fluids which have lower boiling point as working fluid in Rankine cycles, will convert low-grade heat source into high-grade energy (electricity) with higher efficiency. This system not only achieves the goal of recycling, but also reduces the emission of carbon dioxide and other pollutants. So Organic Rankine Cycle (ORC) is considered to be an effective power generation technology driven by low-grade waste heat due to its higher thermal efficiency, lower evaporation and condensation temperatures, relatively simple system and environmentally friendly action.Low-grade heat which can be used by organic Rankine cycle power generation system mainly include industrial waste heat, solar energy, geothermal heat, biomass energy, ocean thermal energy and cold energy of LNG (liquid natural gas). With the purpose of reducing energy consumption, pollutants emission and achieving higher efficiency, this subject analyzed power generation system based on organic Rankine cycle driven by low-grade heat. There are following parts of assignments in this paper:First, based on a lot of research work, this paper made an analysis on structures and operation principle of organic Rankine cycle power generation system, also described the main features and key technical points of ORC system.Secondly, analyzed and optimized usual organic working fluids, then selected three kinds of environmental friendly organics as working fluid, utilized NIST software, programmed under Matlab, made a thermodynamic calculation and analyzed the affecting factors on ORC power generation system.With the purpose of improving system thermal efficiency and work capacity, this paper made a research on properties of improved power generation systems like regenerative and regenerative extraction organic Rankine cycles.Finally, simulated low-grade heat source with hot water, this subject made an experimentally study on organic Rankine cycle power generation system with scroll expander. Through experimental data analysis and conclusion, it is believed that the scroll expander has greater advantages in small and medium style ORC systems driven by low-grade heat. While the design of organic Rankine cycle system needs to be fully considered with working fluid flow, match with evaporation pressure and heat flow rate to have the maximum output power.This research provides theoretical guidance and basic experimental data to further study of power generation system based on organic Rankine cycle, also have a certain theoretical value and practical significance to low temperature heat recovery and utilization technology, as well as energy-saving and emission reduction career. ?...