针对钢铁工业中烧结烟气余热资源丰富但回收利用率低的现状,建立了烧结烟气余热驱动圆筒式两级热电发电装置的有限时间热力学模型.以最大功率输出为目标函数,应用Matlab优化工具箱优化了热电单元尺寸和工作电流,分析了烟气换热通道几何尺寸和多边形边数对优化变量和最优性能的影响,并从经济性角度计算了投资回收周期.结果表明:对于正方形截面管道,烧结烟气为350℃时,优化前功率为5.59 k W,优化后功率为7.97 k W,提高42.39%.热电模块价格为40元/块时,设备回收周期为6年左右.
A thermodynamic model of a thermoelectric generator(TEG)-driven thermoelectric cooler(TEC) device considering Thomson effect and external heat transfer(HT) is established based on the combination of non-equilibrium and finite time thermodynamic theories. The expressions of cooling capacity and coefficient of performance(COP) are obtained. Performances are compared with and without considering Thomson effect using numerical optimization method. The influences of Thomson effect on the optimal performances, optimum allocations of thermoelectric(TE) element number and HT surface area are discussed. The results indicate that Thomson effect decreases the maximum cooling capacity and COP. More TE elements should be allocated to TEG, and more HT area should be allocated to the heat exchanger(HEX) of TEG, the hot-side HEX of TEG and the cold-side HEX of TEC in the design of the device considering Thomson effect. The results obtained can be used to help design TEG-TEC devices.
