Study Of Improving Power Generation Performance Of Thermoelectric Module Based On Phase Change Materials

At present,in the face of dual pressures of energy shortage and environmental pollution,an important green energy conversion technology--thermoelectric power generation is increasingly favored.The thermoelectric module(TEM)has various advantages such as no pollution,quiet,stable,and reliable in the energy conversion process and it has been widely used in many fields.However,due to the low conversion efficiency of TEM,there is still a large amount of thermal energy that has not been recovered and used in time in the application of waste heat recovery.In addition,there is a clear mismatch between the temperature variation of heat source caused by unstable waste heat emissions and the demand for stable output electric power from TEMs.There is still much room for improvement in the efficient recycling of waste heat.The thermal storage technology based on phase change material(PCM),with its technical advantages of being able to store and release thermal energy near a relatively stable temperature,it provides a viable solution to the problem mentioned above.Based on the basic principles of thermal storage and thermoelectric power generation,a TEM combined with thermal storage units which containing PCM was suggested in this paper,and a thermal storage-TEM interconnection performance test system was also designed and built.Through adjusting the thermal properties and the heat storage amounts of PCMs,a series of tests were conducted on the TEM embedded with PCM.The effect of thermal storage on the power generation performance of TEM was studied.Through comparing and analyzing the experimental results,the following conclusions are obtained:(1)After the heat source stops heating,the PCM stored in the thermal storage unit can be used as assistant supplying a large amount of thermal energy and directly act on the hot side of TEM.Meanwhile,the TEM embedded with PCM with higher latent heat is more easily to generate stable electric energy in a short time relatively.(2)It is beneficial to improve the power generation performance of TEM through increasing the heat storage amounts of PCMs from longitudinal and lateral geometrical dimensions.(3)When the heat source stops heating,the PCM with high thermal conductivity rely on its advantage of short thermal response time,it can supply the thermal energy to the hot side of TEM in time.So that the TEM can generates relative stable output voltage for longer time and gets more electric power.In addition,the growth of electric energy obtained by TEM will gradually slow down if continuing to increase the thermal conductivity of PCM.