Designing a thermoelectrically powered wireless sensor network for monitoring aluminium smelters

Abstract Aluminium production cells, Hall-Héroult ‘potlines’, are inefficient and inadequately outfitted with sensors, mostly due to safety concerns with sensor wires between pots, possible interference with existing hardware, high installation costs, and the lack of an easily accessible, maintenance-free, continuous power source for the sensors. A tested solution to accurately measure various process parameters via wireless sensing technology, using either the cell's exhaust heat or steel shell as a thermoelectric power source is presented. Early experiments at Eastalco indicated that the motes, with a few modifications, will be able to operate reliably under industrial conditions, successfully transmitting radio packets through the plants' strong magnetic fields at distances of over 30 m. This article describes the successful testing of wireless measurements of cell parameters, discusses the energy-scavenging thermoelectric power sources and their electronics, and describes the future plans. The authors work is being carried out in conjunction with Alcoa in hopes of improving cell efficiency through better instrumentation.