Study On The Coupling Performance Of Two-stage Serial Organic Rankine Cycle Integrated With Absorption Refrigeration Cycle

With the rapid development of the global economy,the demand for energy increases speedily,and the imbalance between supply and requirement is deepened.So,the full-scale exploitation of renewable energy has become increasingly important.Among them,low-temperature heat sources are widely distributed and have huge reserves,which have extremely high value of utilization.The organic Rankine cycle(ORC)can be effectively combined with low-temperature thermal energy to improve the effective utilization of low-temperature heat sources.In this paper,based on the system of two-stage serial organic Rankine cycle with heating(TSORC-H),the coupling system of two-stage serial organic Rankine cycle integrated with absorption refrigeration(TSORC-AR)is proposed.While the numerical optimization model of the TSORC-AR is established,the differences of the numerical optimization models between the TSORC-AR,the TSORC-H and the system of organic Rankine cycle with heating(ORC-H)are compared.The performances of the TSORC-AR and the TSORC-H are compared and analyzed from the three aspects which are the two stage evaporation temperature,the heat source temperature and the heat rejection temperature,meanwhile the reliability of simulation results is verified by experiments in this paper,then the main conclusions are obtained as follows:(1)In order to measure the comprehensive power generation performance of the TSORC-AR and achieve the goal of low cost and high yield,a new objective function is proposed.The results show that the optimized TSORC-AR improves the comprehensive power generation performance of the organic Rankine cycle and enlarges the two stage evaporation temperature range under the optimal operating condition of the system,which gets more reasonable cascade utilization of the heat in system,more stable operation and wider application range.(2)As the heat source temperature changes from 90? to 150?,the utilization ratio of the heat rejection of absorption refrigeration for the TSORC-AR is getting lower and lower.When the heat source temperature is raised to a certain value,this heat rejection has a hindrance to the performance of the TSORC-AR.According to the variation of the available difference in temperature of the system heat source with the heat source temperature,the cascade utilization of the heat source is much better andthe stability of the heat source exit temperature is better in the TSORC-AR compared to the TSORC-H.This is beneficial to the low-temperature heating of the lower level system as well as the comprehensive utilization of power generation and heating.(3)It is selected that the absorption refrigeration temperatures are 75?,80?and 85?.Comparing the TSORC-AR to the TSORC-H,it is known that the increase of the heat rejection temperature is beneficial to the power generation performance of the TSORC-AR at a higher heat source temperature.At the same time,according to the demand of the actual load,the heat rejection temperature in the TSORC-AR and the mass flow rate of heat source fluid can be adjusted to get the appropriate ratio of cooling and heating.(4)The experimental value of the power generation of the experimental system is close to the simulated value,and the relative error is 12.4%,which verifies the reliability of the simulated data.