热释电效应用于低温余热动力回收的研究

Experimental Study on Applying the Pyroelectric Effect to Low-Grade Waste-Heat Power Recovery

以热释电效应用于低温余热动力回收为背景,对采用40μm厚的热释电材料共聚物偏氟乙烯 三氟乙烯(P(VDF TrFE)(60/40))薄膜作工作介质的热释电转换循环进行了实验研究.实验结果表明:在避免失去自发极化的适宜工况条件下,可以直接实现连续的热释电转换循环;施加电压对热释电电流和热释电转换输出的电能密度都有较大的影响,在相同的温度范围和变化率下,随着施加电压的增加,热释电电流增大;提高低端电压和高低端压差有利于增加输出电能密度.在温度为40～70℃的范围内,当高端电压为900V(电场强度为225kV/cm)时,热释电转换净输出电能密度(单位体积热释电材料所生产的电能)可达40mJ/cm3.这种热释电转换将在低温余热动力回收领域具有可能的应用前景.

The pyroelectric conversion cycle of heat to electricity is conducted adopting a single copolymer P(VDF-TrFE) (60/40) film of 40 μm thickness for low-grade waste-heat power recovery. Experimental results show that the continuous pyroelectric conversion cycle can be directly realized under the proper conditions without the loss of spontaneous polarization. The external voltage strongly affects the pyroelectric current and electrical energy output. Within the same temperature range and at the same changing rate, the pyroelectric current is enhanced with increasing external voltages. Heightening lower voltage and the difference between upper voltage and lower voltage facilitates electrical energy output. The net output energy density of pyroelectric conversion cycle reaches 40 mJ/cm3 under the condition of the temperature 40-70°C, upper voltage 900 V (electric field intensity approaches to 225 kV/cm). This heat-to-electricity conversion can be applied to low-grade waste-heat power recovery.