Non-intrusive Water Flow Rate Measurement: A TEG-powered Ultrasonic Sensing Approach

This paper proposes a thermoelectric generator (TEG)-powered ultrasonic sensing system for non-intrusive water flow rate measurement. The limited power provided by the TEGs is handled by a dedicated energy management unit (EMU), allowing reliable sensing, computation, and transmission tasks. First, we introduce the delta time-of-flight (ΔToF)-based ultrasonic sensing and thermoelectric energy generation theory. Then, the design is given, followed by the system evaluation under different harvesting conditions to show their impact on average sensing and transmission times. The results revealed that our method could achieve high measurement accuracy (±1.4%), comparable to intrusive and battery-powered counterparts, thereby offering a "plug&play+deploy&forget" hybrid solution.