Batteryless Sensor Devices for Underground Infrastructure-A Long-Term Experiment on Urban Water Pipes

Drinking water is becoming increasingly scarce as the world's population grows and climate change continues. However, there is great potential to improve drinking water pipelines, as 30% of fresh water is lost between the supplier and consumer. While systematic process monitoring could play a crucial role in the early detection and repair of leaks, current practice requires manual inspection, which is both time-consuming and costly. This project envisages maintenance-free measurements at numerous locations within the underground infrastructure, a goal that is to be achieved through the use of a harvesting device mounted on the water pipe. This device extracts energy from the temperature difference between the water pipe and the soil using a TEG (thermoelectric generator), takes sensor measurements, processes the data and transmits it wirelessly via LoRaWAN. We built 16 harvesting devices, installed them in four locations and continuously evaluated their performance throughout the project. In this paper, we focus on two devices of a particular type. The data for a full year show that enough energy was available on 94% of the days, on average, to take measurements and transmit data. This study demonstrates that it is possible to power highly constrained sensing devices with energy harvesting in underground environments.

Automated summary

Drinking water scarcity is a growing concern due to population growth and climate change. Improving drinking water pipelines has significant potential, as 30% of fresh water is lost during distribution. Current manual inspection for leaks is time-consuming and expensive, but this project aims to achieve maintenance-free measurements through energy harvesting devices mounted on water pipes. The study demonstrates the success of powering sensing devices underground with energy harvesting, with enough energy available for measurements and data transmission on an average of 94% of days throughout the year.