TEG-Self-Powered System for Wireless Sensing Node Operating in Aqua-Greenhouse

This research focuses on harnessing excess heat energy in Aquaponic greenhouses-a system combining vegetable and fish cultivation with water circulation, where a perpetual temperature difference exists between the greenhouse air and the water in hydroponic vegetable tubes. Our objective is to convert this temperature difference into electric power for using in wireless IoT sensing systems. Nineteen thermoelectric generators (TEG-12708) were evaluated in a laboratory environment to determine their internal resistance and corresponding load resistance for experimental energy surveys in greenhouses. The maximum output power reached 699.38 µW when the temperature difference across the TEG was 3°C. Furthermore, we successfully demonstrated a sensing system driven by the realistic ambient temperature environment by integrating the TEG with other electronic components, including a DC-DC converter, power management circuit, supercapacitor, and sensors. Under aqua-greenhouse conditions, the harvested temperature difference across the TEG was 3.5°C, corresponding to the TEG's output power of 0.55 mW. The output of the DC-DC converter could reach over 8 V. This work opens up new opportunities for TEGs to harness ambient aqua-greenhouse energy and convert it into usable electricity for wireless IoT sensing systems.