Intelligent distributed heater used for industrial applications

An electrically conductive polymer heating material with "distributed intelligence" has found many applications in the industrial, commercial and consumer world. These applications include electrical heat tracing (heating of pipes with long line cable heaters) in process plants, snow melting in concrete, energy savings in hot water distribution systems, and frost heave prevention under refrigerated structures. The heater core displays an increasing electrical resistivity with increasing temperature. The material property is coupled with parallel circuitry to produce a distributed electrical heater with local intelligence, the self-regulating heater. This paper includes an explicit example of thermal and electrical parameters of such a heater used in frost heave prevention of large LNG tanks around the world. Finite element analysis (FEA) of these systems are shown to provide an analytical tool in projecting performance for large thermal masses with time constants of up to 60 days. The self-regulating heater provides both design and performance reliability not found in previous systems.