Thermoelectric water meter energy harvesting

Domestic electronic water meters are installed by water meter utility companies to accurately measure household water usage for billing purposes, progressing from simple electromechanical systems to state-of-the art volumetric electronic smart meters with RF radio transmission, remote reading, and automatic billing capability. The motivation for this work is to replace, or increase the lifetime of, the on-board lithium-ion battery installed in electronic water meters with a thermoelectric energy harvesting solution to create a business advantage. Practical field experiments at several different water meter installations in the UK, USA, and Australia have demonstrated a temperature difference can exist between the top-side and bottom-side of a water meter, and between several different areas of the meter and the surrounding air. This temperature difference can be harnessed to generate electrical power using thermoelectricity. A prototype thermoelectric water meter energy harvesting system has been designed, and experiments demonstrate the system will operate when a temperature difference is present across the thermoelectric module, giving an output voltage of 3.7V to power the water meter electronics directly or to provide a charge current for the existing lithium-ion battery to increase its lifetime. The work concludes it is feasible, although still challenging, to develop a solution for a novel thermoelectric powered water meter. Further work is required to address the commercial challenges that exist, develop and optimise the prototype solution into a production ready prototype, and conduct further tests using a standard UK domestic water profile at a UK water meter test site.