An autonomous sensor with energy harvesting capability for airflow speed measurements

In several environments modest ambient airflows are present, for example, in air-conditioning ducts, in outdoor environment, or in moving vehicles. Furthermore, an airflow speed measurement is an important indicator, for the energy efficiency in the regulation of the conditioning implants. An autonomous sensor placed in a duct and powered by an electromechanical generator scavenging energy from the airflow has been designed and tested. The airflow speed is measured trough the rotor frequency of the electromechanical generator. When the external readout unit is active the electromagnetic field is used to power the autonomous sensor system and transmit the data. A set of tests on three airflow harvesters using resistive loads was conducted to demonstrate their energy conversion potentials. An experimental system has been designed and realized demonstrating that the airflow harvester can power the autonomous sensor permitting airflow speed measurements.