Study On Thermoelectric Conversion Device For Forest Soil Temperature Difference

The modern monitoring technology of the natural environment of the forest and the biological population cannot be separated from the wireless sensors.Wireless sensors have the advantages of convenient and rapid monitoring,low power consumption,which are suitable for working in forest areas.Due to the special nature of the forest environment,for example many trees,vegetation,and high crown density,it leads to difficulties in the supply and maintenance of wireless sensors.To solve the problem,this study designed a thermoelectric power generation device that can supply power to the forestry wireless sensor network in-situ,and test the power generation performance.This thermoelectric power generation device is characterized by using the temperature difference between the forest soil and the air to perform thermoelectric conversion.It generates electrical energy to power wireless sensors.The device is mainly composed of a gravity heat pipe and thermoelectric power generation sheets(TEG).A simulation experiment was conducted indoors to verify the feasibility of the thermoelectric generator.Based on this,optimization and improvement were performed.The application was performed under outdoor natural conditions in the later period and experimental analysis was performed.Manually controlling the temperature difference in the room,the power generation results show when the maximum temperature difference reaches 20?,the maximum instantaneous voltage with one TEG is 13.5mV.The maximum instantaneous power value is 0.3mW;the maximum instantaneous voltage with 4 TEG is 63.5mV.The instantaneous power value is 0.61mW.The maximum instantaneous voltage with 8 TEG is about 292.5mV,and the maximum instantaneous power value is 13.8mW.Therefore,the thermoelectric generation device selected 8 TEG.The device was placed in a nursery forest area and subjected to experiments.Affected by weather conditions such as wind,rain and snow,the maximum instantaneous voltage generated by the outdoor thermoelectric generator was 63mV.The instantaneous electric energy was about 0.82mW.After installing the cooling fins on this device,the maximum instantaneous voltage generated is 466mV.The instantaneous power is approximately 43.3mW.The power provided by the device satisfies the power requirements of the wireless sensor.