When considering a new electric heating project, engineers must look at three components: the heater, the power control, and the installation. The installation will require transformers, wiring, terminations, conduit runs, hangers, wire pulls, and inspections. For a typical 2400 kW (8.2 MMBtu/hr) 24-circuit project operating at 480V, Table 1 shows the costs including installation. As indicated, installation cost easily exceeds that of the equipment and start up service, significantly boosting project cost.
DirectConnect medium voltage technology operates process heat equipment directly off an existing 4160V up to 7200v distribution system. This reduces or minimizes the need for dedicated voltage step-down transformers. When operating multi-megawatt systems, this cost avoidance can be substantial, in this instance, medium voltage offers a savings of over $250,000.
Chromalox medium voltage systems Eliminate or Reduce Transformers,
Require Fewer and Smaller Gauge Wires, and Save Installation Labor.
Additionally, medium voltage technology for electric process heating drastically reduces the amperage draw for the same heat output. Operating process heating equipment at an industry standard 4160V reduces amperage by a factor of nine. Reduced amperage permits fewer wires with smaller diameters compared to the 480V source.
Converting from 480V to 4160V for the same heating value drops the number of circuits required from 24 to 2, greatly reducing wire, contactors, fusing, and installation labor. Table 2 shows the project cost for an equivalent 2400 kW (8.2 MMBtu/hr) system operating at 4160V. In this case the installation costs are less that 10 percent of the equipment and startup service costs. Project costs are about a quarter of a million dollars less than the low voltage alternative. Installation time would be reduced by an estimated 80%.