综合评价模型联合遗传算法的混合工质ORC系统性能研究

Comprehensive evaluation model combined with genetic algorithm for the study on the performance of ORC system with zeotropic mixture

采用R601a/R600作为工质回收工业余热,并以系统的热力学性能(输出功率Wnet、热效率ηth、?效率εex)、经济性能(投资成本回收周期ICPP、单位输出功率所需换热面积APR)、环境影响(CO_(2)当量排放ECE、环境?代价Exc)为评价指标,采用AHP-和积法确定不同评价指标的权重并结合遗传算法对系统进行综合分析。结果表明,综合评价指标F1的目标函数的权重大小依次为:环境影响>经济性能>热力学性能。当R601a/R600工质配比为0.33%/99.67%,蒸发温度为137.2℃时,W_(net)、η_(th)、ε_(ex)、APR、ICPP、ECE和E_(xc)分别为62.9 kW、15.8%、48.7%、4.3 m2/kW、6.6 a、25.0 t、4.0 W。得到的ECE和Exc与平衡权重的TOPSIS相比,分别降低了45.9%和57.0%。这说明F1对环境影响更为重视,能根据不同权重给予实际工程更多的参考方案,比传统TOPSIS更有指导意义。

The system uses R601a/R600 as the working fluid to recover industrial waste heat.It uses the thermodynamic performance(output power Wnet,thermal efficiencyη_(th)and exergy efficiencyε_(ex)),economic performance(investment cost payback period ICPP,heat exchanger area per unit power output APR),and environmental impact(emissions of CO_(2)equivalent ECE,environmental exergy cost E_(xc))as evaluation indicators,and the weights of different evaluation indicators are determined by the AHP-sum-product method and combined with the genetic algorithm to conduct comprehensive analysis and optimization of the system.The results show that when the weight of the objective functions of the comprehensive evaluation index F1 is in the following order:environmental impact>economic performance>thermodynamic performance.When the mass fraction ratio of R601a/R600 is 0.33%/99.67%and the evaporation temperature is 137.2℃,W_(net),η_(th),ε_(ex),APR,ICPP,ECE and E_(xc)are 62.9 kW,15.8%,48.7%,4.3 m^(2)/kW,6.6 a,25.0 t,and 4.0 W,respectively.The ECE and Exc obtained are reduced by 45.9%and 57.0%,respectively,compared with those obtained by TOPSIS based on balanced weight.This shows that F1 pays more attention to environmental impact,and can give more reference plans for actual projects according to different weights,which is more instructive than traditional TOPSIS.