采用菲涅耳透镜汇聚太阳辐射,提高半导体温差发电组件的热端温度,冷端利用散热片进行散热.从热流密度的角度建立了半导体温差发电片理论分析模型,实验基于稳态的条件下,忽略冷热端之间以及电臂间的空气对流和辐射,研究菲涅耳聚光下半导体温差发电组件的性能,推导出了半导体温差发电片的温度梯度dT/dx关系式,获得了输出电流、输出功率及热电转换效率的表达式.研究表明:随着电阻比率a(RL/R)的增大,半导体温差发电器件的输出电流I减小,输出功率P和转换效率ηhe先增大后减小,且在a=1时,其输出功率和转换效率最高.随着温差比率b(?△/TH2)的增大,无论a取何值,其输出功率P和转换效率ηhe均增大.实验研究中,半导体温差发电片应偏离菲涅耳透镜焦平面一定距离以获得较好输出特性.通过温差发电片的不同串并联组件可获得相应输出电压.
Using Fresnel concentration to collect solar irradiation, the hot-end temperature of the semiconductor thermoelectric generator is enhanced, and the cold end is cooled through a radiator in air. For studying the performance of thermoelectric module under solar Fresnel concentration, a theoretical model of thermoelectric generator under steady condition is built from the perspective of energy flux. The model neglects the convection and radiation heat transfer between the cold and hot end and between the arms, and simplifies the heat conduction only along the arm. Utilizing this model, the temperature gradient on thermoelectric generator(d T dx), the output current(I), the output voltage(V), and the output power(P) of thermoelectric generator are derived, and the influences of the resistance ratio a RL R) and the temperature difference ratio b T TH2) on generator output performance under a certain structure parameters of thermoelectric generator are discussed. The results show that with the increase of resistance ratio(a), the output current(I) decreases, however the output power(P) and the conversion efficiency(ηhe) first increase, then decreases. When the resistance ratioa, the output power(P) and the conversion efficiency(ηhe) reach their maximum values. When the resistance ratio(a) is smaller, the output power(P) increases rapidly with the increase of the resistance ratio(a). When the resistance ratio(a) is larger, the output power(P) decreases slowly with the increase of the resistance ratio(a). With the increase of temperature difference ratio(b), the output power(P) and the conversion efficiency(ηhe) increase, no matter what the value of the resistance ratio(a) is. It verifies the sensitivity of the output power(P) to the temperature difference. Therefore, with a certain figure of merit, the appropriate adjustment of temperature difference ratio(b) may improve the output power(P) and the conversion efficiency?