密闭空间串联式两级热电制冷器瞬态特性分析

Analysis on Transient Characteristics of Series Two-stage Thermoelectric Cooler in Confined Space

综合考虑包括汤姆孙效应在内的热电材料内部效应,建立工作在绝热表面空间内和非绝热表面空间内的串联式两级热电制冷器计算模型,通过分析冷热端温度、级间温差等参数的瞬态变化对两级热电制冷器性能的影响,得到了制冷空间温度、制冷量、制冷系数等性能参数随时间的变化规律.分别改变输入电流、热电偶数量和热电偶分配比,对比分析了2种模型的最低制冷温度、降至稳定温度耗时、制冷量和制冷系数的变化规律.结果表明,与相同条件的单级热电制冷器相比,两级热电制冷器降温所需时间较长但可达到更低的制冷温度;适当增大电流可以有效减少制冷耗时,且存在最佳电流、最佳热电偶数量和最佳热电偶分配比,分别使制冷空间温度最低,制冷器制冷系数最大.

Comprehensively considering the various thermoelectric effects including the Thomson effect,a computational model of a series two-stage thermoelectric cooler that works in adiabatic surface space and non-adiabatic surface space is established.The effects of transient changes of parameters such as cold and hot junction temperature,and interstage temperature difference on the performance of a two-stage thermoelectric cooler are analyzed.The variation law of performance parameters such as cooling capacity,cooling space temperature and coefficient of performance with time is obtained.When the input current,the number of thermoelectric couples and the distribution ratio of thermoelectric couples are changed,respectively,the minimum cooling temperature,the time-consuming to reach the stable temperature,the refrigerating output and the change of the cooling coefficient of the two models are compared.The results show that,compared with single-stage refrigerators under the same conditions,two-stage refrigerators take longer to cool down but can achieve lower cooling temperatures.Appropriately increasing the current can effectively reduce the cooling time.There exists the optimal current,the number of thermoelectric couples and the distribution ratio of thermoelectric couples,which make the temperature of the cooling space the lowest and the coefficient of performance of the cooler to be the largest,respectively.