基于相变蓄热和热电转换的低品位热能热/电联合回收实验研究

EXPERIMENTAL STUDY ON LOW-GRADE HEAT RECOVERY METHOD USING LHTES AND TEG FOR COMBINATION GENERATION OF THERMAL AND ELECTRICAL ENERGIES

针对低品位热能回收，提出一种采用相变蓄热及热电转换技术以实现热能，电能联合回收利用的新方法，回收的热能用于加热连续供给的冷媒水并同时发电。搭建实验系统对其热／电回收性能进行实验研究，结果表明：综合相变材料（PCM）温度及温差变化曲线可较好地反映出系统的相变蓄热规律，冷媒水温升及热电转换量明显且存在由PCM相变效应引起的平稳变化段，占PCM主要相变阶段的16．7％。增加冷媒水流量及热电转换单元（TEM）数量会降低冷媒水温升、提高热电转换量。冷媒水流量、热源输入功率和TEM数量为影响热／电回收性能及蓄、放热时间比的主要因素。间歇性蓄、放热循环实验中冷媒水温升和热电回收功率分别稳定在6—13℃和0.020-0．085W，显示该文提出的热回收方法对间歇性热能回收具有较好的稳定性。

A hybrid low-grade heat recovery method using latent heat thermal energy storage （LHTES） and thermoelectric generation （TEG） for combination generation of thermal and electrical energies was studied, in which the recovered heat was purposely absorbed by continuously supplied cooling water and converted into electrical energy at the same time. The experiments were done to study the thermal and electrical output characteristics and the related influencing factors. The experimental results show that combination of temperature and temperature difference variations of phase change material （PCM） can reveal the phase change heat storage phenomena well. The temperature rise of cooling water and converted thermoelectric power are significant, and there exist moderate sections caused by the phase change effect of PCM, which take 16.7% of the main phase change period of PCM. Increasing the flow rate of cooling water and thermoelectric module （TEM） quantity can decrease the temperature rise of cooling water and enhance thermoelectric power. The flow rate of cooling water, input power of heat source and TEM quantity are main factors influencing thermal and electrical output performances, ratio of heat storage duration to heat release duration. The results of intermittent heat storage and release experiments show that the temperature rise of cooling water and thermoelectric power vary within 6 -13 ℃ and 0.02 -0.085 W, respectively during six-cycle periods, which demonstrates the stability of the hybrid waste heat recovery method for intermittent heat source.