Mechanism And Experimental Study On Solar-electric Solid State Engine

A solar-electric solid state engine system is designed and constructed based on solid state energy conversion technology and pyroelectric effect in this work.The solid working medium of the engine is a thermoelectric conversion cell made up of silver film,PZT ceramic film and brass film.It can realize solar,thermal,micro mechanical deformation and electric energy conversion and electricity output.The energy conversion is enhanced by constructing a non-equilibrium thermal field.The effects of non-equilibrium thermal field on the performance characteristics of the engine are explored and analyzed.The PZT ceramic thin film of the thermoelectric conversion cell has pyroelectricity and can create charges owing to temperature change.To guarantee continuous electric energy output,the frequency of energy input requires to be regulated and controlled,so the temperature will vary with time constantly.To enhance the energy conversion,the absorptivity distribution of the thermoelectric conversion cell is designed to be non-equilibrium based on the third pyroelectric effect.Therefore the thermal field constructed is non-equilibrium and the stress gradient inside the material enhances the energy conversion.The response of the engine to non-equilibrium thermal fields is investigated with its output voltage in the experiment.The experimental results show that:In the state that the absorptivity distribution of the thermoelectric conversion cell is not modified,the temperature distribution is nearly equilibrium.In the state that the absorptivity is modified,the temperature distribution is non-equilibrium.A great temperature gradient exists and non-equilibrium thermal field is constructed.The temperature of both states increases or decreases alternately with time,but the average temperature and amplitude after modifying the absorptivity are higher than these not.In the same input power condition,the high absorptivity patterns have the same areas,but the non-equilibrium thermal fields constructed by different absorptivity distributions have different structural features,so they have different effects on voltage response.The voltage of the state that absorptivity distribution is modified is larger than the voltage of the state that absorptivity distribution is not modified.In these states that absorptivity distribution is modified,the voltage of the state whose high absorptivity pattern is eccentric circular is largest.The amplitudes of output voltages increase 82% and 158% respectively,when focal temperature are 130℃ and 200℃.