Techno-economic performance of two-stage series evaporation organic Rankine cycle with dual-level heat sources

Abstract With the increasing of fossil energy crisis and environmental pollution, the development and utilization of renewable energy has become a hot spot in recent years. Based on two-stage serial organic Rankine cycle system of single heat source, the two-stage series organic Rankine cycle system of double heat source is proposed in this paper to realize cascade utilization of heat sources with different temperatures. The composite heat source grade is correlated with the two-stage series evaporation temperature to improve the power generation power and economic benefit of the system. Taking R245fa as an example, the mass flow rate of heat source is 10 kg/s, and the effects of evaporation temperature and heat source temperature on the net output power, thermal efficiency, exergy efficiency, electricity production cost and investment payback period of organic Rankine cycle, two-stage serial organic Rankine cycle system of single heat source and two-stage series organic Rankine cycle system of double heat source are optimized and analyzed. It is found that the electricity production cost and investment payback period of two-stage series organic Rankine cycle system of double heat source are always the smallest, followed by two-stage serial organic Rankine cycle system of single heat source, and the largest is the electricity production cost and investment payback period of organic Rankine cycle system. At the same time, it is found that two-stage series organic Rankine cycle system of double heat source is more suitable for low-temperature heat source.