Soil-Monitoring Sensor Powered by Temperature Difference between Air and Shallow Underground Soil
Soil-Monitoring Sensor Powered by Temperature Difference between Air and Shallow Underground Soil
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DOI：
10.1145/3380995
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发表时间：
2020-03-01
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影响因子：
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通讯作者：
Kawahara, Yoshihiro
中科院分区：
文献类型：
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作者：
Ikeda, Natsuki;Shigeta, Ryo;Kawahara, Yoshihiro
能量收集（EH）技术对于无线传感器网络的半永久操作是有用的，特别是对于农业监测，因为网络需要安装在电力供应不可用的大区域中。在本文中，我们提出了一种用于农业的无电池土壤监测传感器，该传感器利用近地表空气和浅层地下土壤之间的温差，使用热电发电机（TEG）。由TEG驱动的系统的性能主要取决于TEG的热侧和冷侧之间的平均温度（（T）over bar）和TEG两端的温差（Δ T）。如果（T）过bar较低且Delta T较小，则获得足够的功率来驱动无线微控制器单元具有挑战性;然而，通过我们的专用电路和热设计（包括热电路的阻抗匹配和抑制热损失），传感器可以从30 cm深度的空气和地下土壤之间的温差中平均收获超过100微瓦。能量采集器的性能进行了评估，使用从不同的农田收集的温度数据，并通过原型实现的数值分析。此外，原型被部署到日本和印度的农田。田间试验结果表明，该样机平均可收获100 -370亩W的电能，并驱动无线微控制器单元进行土壤监测。
Energy harvesting (EH) technologies are useful for the semi-permanent operation of wireless sensor networks, especially, for agricultural monitoring as the networks need to be installed in large areas where power supply is unavailable. In this paper, we propose a battery-free soil-monitoring sensor for agriculture, which leverages the temperature difference between near-surface air and shallow underground soil using a thermoelectric generator (TEG). The performance of systems driven by the TEG mainly depends on the average temperature between the hot and cold sides of the TEG ((T) over bar) and the temperature difference across the TEG (Delta T). If (T) over bar is low and Delta T is small, it is challenging to earn enough power to drive wireless microcontroller unit; however, with our dedicated electric circuit, and thermal designs including impedance matching of thermal circuit and suppression of heat loss, the sensor can harvest more than a hundred microwatt on average from the temperature difference between the air and underground soil at a depth of 30 cm. The performance of the energy harvester is evaluated both by numerical analysis using temperature data collected from various farm fields and by a prototype implementation. Moreover, the prototype was deployed to farm fields in Japan and India. Our field experiment results revealed that the prototype could harvest 100 mu W-370 mu W on average, and drive a wireless microcontroller unit to perform soil monitoring.