Design and technoeconomic assessment of a self-powered thermoelectric steam trap monitoring system for energy efficiency and decarbonization in industrial steam networks

Abstract

Industrial steam systems are major energy consumers in manufacturing, and undetected steam-trap failures cause persistent steam losses, increased boiler fuel demand, and avoidable carbon emissions. This study evaluates a self-powered monitoring concept in which thermoelectric generators (TEGs) harvest heat at steam-trap locations to operate duty-cycled sensing and LoRaWAN communication nodes without routine battery replacement or dedicated field wiring. The steam network of a real textile facility was modeled in Engineering Equation Solver and assessed through integrated energy, exergy, economic, and environmental analyses. At the nominal conditions of 170 °C steam temperature and 25 °C ambient temperature, the calculated pipeline heat loss was 27.91 W/m; a single TEC1–12706 module generated 0.1722 W, corresponding to 6.887 W and 55.09 kWh/year for the 40-trap network. The resulting energy and exergy efficiencies were 1.02% and 5.86%, while a single module supplied approximately 129 times the assumed average monitoring-node demand. Sensitivity analyses of steam temperature, cold-side thermal resistance, and module number confirmed that performance is governed primarily by the available temperature difference and heat-rejection conditions. The complete installed network cost was estimated at 2890–9200 $, with 4800 $ adopted for the moderate scenario. Electricity generation alone yielded an impractical payback period of 580.8 years; assumed monitoring-enabled fuel-demand reductions of 2%, 5%, and 10% reduced it to 2.56, 0.98, and 0.48 years, with corresponding scenario-based total savings of 23.75, 59.35, and 118.7 t CO₂/year against only 0.0117 t CO₂/year from direct TEG output. These values are potential, scenario-based monitoring-enabled benefits rather than field-verified savings. The results indicate that TEGs are more appropriately regarded as autonomous power sources for intelligent steam-trap monitoring than as primary electricity-generation devices.