Experimental Study On The Effects Of Multiple Nonuniform Thermal Fields On The Photothermal Electric Conversion Efficiency Of PZT Solid State Heat Engine

In this paper a PZT solid-state heat engine is designed based on the pyroelectric effect of PZT material.This kind of energy conversion device can collect solar energy and thermal energy in the natural environment and convert them into the electric power.The engine has significant advantages such as low carbon and environmental protection,low price,and also it can be used to effectively repair the damaged ecological environment.Firstly,based on the basic theory of pyroelectric effect,the working principle of PZT solid state heat engine is analyzed,and the theoretical temperature distribution and theoretical output voltage are derived.Secondly,by means of patterning the period absorptivity distribution on the surface of PZT solid state heat engine,different multiple non-uniform heat fields were constructed.Finally,the surface temperature distribution and output voltage of these engines are studied under the conditions of constant photothermal excitation and frequency-modulated photothermal excitation,and also the influence of multiple non-uniform thermal interactions on the efficiency of photothermal electrical conversion of solid heat engines are analyzed to determine the optimal thermal field distribution.The results show that:Under the constant photothermal excitation of 500 W,the temperature distribution in the engine without surface treatment is evenly distributed and the temperature is low.The temperature distribution in the engine modulated by absorptivity is not uniform,the value of temperature is high,and the rate of temperature change is large.The value and the rate of temperature change in 5-tripe distribution are the highest.Under the same input power condition,the voltage output of the engine without surface treatment is also lowest among others,the maximum voltage output is 760 m V,maximum voltage output of the 5-stripe heat engine is the largest,up to 2.96 V,the voltage increased by 290% compared with voltage output of the engine without surface treatment.Under 500 W FM photothermal excitation,the temperature and the rate of temperature change of the seven heat engines all changed periodically,but the amplitude of the change was different.The amplitude of temperature change of engine without surface treatment is the lowest,and the amplitude of the rate in temperature change is also the lowest.The amplitude of temperature change of 5-stripe heat engine is the highest,and the amplitude of temperature change rate is also the highest.Under the same input power condition,the voltage output value of the engine without surface treatment is also lowest,the voltage value fluctuates in the range of-328 ～ 384 m V,the voltage output value of the 5-stripes heat engine is the largest,and the voltage value fluctuates between-1.12 ～ 1.32 V,which is 240% higher than that of engine without surface treatment.Thus,it can be seen that the construction of multiple non-uniform heat fields can effectively improve the efficiency of photothermal electric conversion of PZT solid state heat engine.