Abstract: The present invention involves calibrating a control system to enable resistance-based control of a heat tracing circuit, that includes characterizing a piece of heat trace to determine a relationship between resistance and temperature, allowing for more precise control. Also described are different methods for practical resistance-based control of a heat trace system. Further described are several methods to monitor heat trace: including methods to enhance monitoring capabilities using a system operating model; comparison to historical operating data; and inclusion of information from external sources. Also provided is a method by which a piece of heat trace of unknown length and power factor can be controlled using the resistance-based method when other system information is available.

Abstract: A snow and ice melt system having one or more zones, each including one or more heaters, and having one or more controllers configured to use a power output of each heater and an average temperature of each zone to determine operational control of each heater to achieve a specified result. Hydronic or resistive heaters could be used. The controllers may be configured to use a system temperature response over time to determine if a phase change of the snow or ice is occurring. The phase change might indicate that snow or ice is present on a zone and is melting. Use of a first derivative of the system temperature response over time might determine a percentage of a zone covered by snow or ice. Use of a second derivative of the system temperature response over time might determine whether melting is complete.

Abstract: Ice mitigation for bridge cables is provided by a system having a plurality of heaters on one or more bridge cables, extending parallel to a longitudinal axis thereof, arranged in a plurality of heater sections, and configured to heat an outer surface of the bridge cables, and a control system including one or more controllers configured to individually activate and regulate heating output of the heater sections to prevent snow or ice from falling from the bridge cables. The heater sections can be arranged radially, about a circumference of the bridge cables, and/or axially, end to end along a length of the bridge cables, so that power can be individually directed to the heater sections to account for differing heating requirements at different radial and/or axial aspects of the bridge cables.

Abstract: A snow and ice melt system having one or more zones, each including one or more heaters, and having one or more controllers configured to use a power output of each heater and an average temperature of each zone to determine operational control of each heater to achieve a specified result. Hydronic or resistive heaters could be used. The controllers may be configured to use a system temperature response over time to determine if a phase change of the snow or ice is occurring. The phase change might indicate that snow or ice is present on a zone and is melting. Use of a first derivative of the system temperature response over time might determine a percentage of a zone covered by snow or ice. Use of a second derivative of the system temperature response over time might determine whether melting is complete.

Abstract: Ice mitigation for bridge cables is provided by a system having a plurality of heaters on one or more bridge cables, extending parallel to a longitudinal axis thereof, arranged in a plurality of heater sections, and configured to heat an outer surface of the bridge cables, and a control system including one or more controllers configured to individually activate and regulate heating output of the heater sections to prevent snow or ice from falling from the bridge cables. The heater sections can be arranged radially, about a circumference of the bridge cables, and/or axially, end to end along a length of the bridge cables, so that power can be individually directed to the heater sections to account for differing heating requirements at different radial and/or axial aspects of the bridge cables.