May 2023 Volume 5

ENERGY

Results Before proceeding into specific information about costs, it must first be noted that the survey results are specific to the IH studied. Any variation in EP billing rate, material, temperature, throughput rate, coil configuration, or power supply topology will directly impact the final utility cost. Calculating Electricity Costs As the client’s energy pricing is proprietary, the total energy cost was calculated from the rate provided by a selected municipal electric utility. The utility “Cleveland Public Power” (CPP) was chosen, and the CPP electricity rate schedule [1] is shown in Table 1.

The monitor was set to record measurements at close intervals and retain the data in the internal memory. From this data, values for kilowatts (kW), kilowatt-hours (kWhr), reactive power (kVAR), harmonics, and other characteristics were analyzed and categorized. Chart 1 is an example of the detail provided by the power monitoring.

Chart 1: Load power characteristics The operating parameters were also recorded, including billet size, composition, throughput rate, and IH power settings. All heated billets were counted, including those heated and rejected, along with any downtime. The survey lasted 5.65 hours, during which a consistent one-hour production run was attained, providing steady-state results to base calculations. Any changes to IH power and throughput rate are included in the analysis.

Table 1: Municipal utility industrial electricity rate schedule To estimate monthly cost the electrical energy use data was extrapolated over an 8-hour/day, 26-day month and calculated using the EP rates. The result shown in Table 2 is that the monthly operating cost for a single induction heater at the specified throughput is approximately $9,015/month.

Table 2: Electricity cost analysis

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