Design of hydro electromagnetic and piezoelectric energy harvesters for a smart water meter system

Abstract We designed hydro electromagnetic and piezoelectric energy harvesters to power a smart water meter system. Usually, in water pipes, a water meter is necessary for checking water flow conditions within the pipe. However, supplying electrical energy to the water meter is a critical problem. The use of batteries or a direct connection to a power socket for this purpose causes other problems such as requiring regular replacement of the batteries and potential electric shock caused by water leakages. Furthermore, flow rate is checked at a specific location, typically the basement of the building. By constructing a smart water meter system which is self-powered by the energy harvesters and can transmit flow rate data wirelessly, time and effort could be saved. In addition, the proposed smart water meter system can detect water leakages in the pipes. In this paper, a turn-buckle type stainless steel waterwheel with a diameter of 90 mm and two pole magnets was proposed, as turn-buckle type waterwheels do not require any hole in the pipe unlike other self-powered water meters that use DC motor-based energy generation. In addition, by designing non-contact energy harvesters using magnets, the proposed energy harvesters are semi-permanent. The performance of the manufactured energy harvesters was analyzed under experimental conditions in a flowing water setup composed of a PVC pipe and a water pump. The electrical output power of the energy harvesters was measured under various load resistance conditions. The maximum root mean square (RMS) output power of the electromagnetic and the piezoelectric energy harvesters were 648 mW at 200 Ω and 0.196 mW at 10 kΩ, respectively. The generated electrical energy works differently. The energy harvested by the electromagnetic energy harvester is used to be a power source for the smart water meter system while the energy harvested by the piezoelectric energy harvester is used to be a water leakage detector for the water leakage warning system.