Rotational Molding worked example

Energy Per Cycle with oven and machine connected load of 30 kW: a worked example

What does the result look like when oven and machine connected load reaches 30 kW? The full calculation is worked below with real intermediate numbers. Use it when energy per cycle in rotational molding is up for an upgrade and you want a defensible savings story.

The inputs for this scenario

  • Oven and machine connected load: 30 kW (raised for this scenario; the documented default is 12)
  • Cycle runtime (heat plus cool): 8 hr (unchanged)
  • Electricity or gas rate: 0.12 $ / kWh (unchanged)
  • Parts produced in the cycle: 1,000 units (unchanged)

Working through the calculation

  • Applying the documented formula (Energy cost = connected load × runtime × energy rate) to the inputs above produces each figure below.
  • At this operating point the engine returns 28.8 $ / unit for energy cost, the number this scenario is built around.
  • At this operating point the engine returns 240 kWh for energy used.
  • At this operating point the engine returns 0.03 $ / piece for cost per piece.
  • At this operating point the engine returns 3.6 $ / hr for hourly cost.

How this compares with the baseline

  • Against the tool's baseline example, where oven and machine connected load sits at 12 kW and the headline result is 11.52 $ / unit, this scenario comes in 150% above the baseline at 28.8 $ / unit.
  • A figure at this level is achievable when oven and machine connected load is genuinely sustained, not just peaked for a shift. It treats connected load as constant across the cycle; real ovens modulate between heat-up and hold, so measured kWh from a meter may differ from the nameplate-load estimate.

Results at a glance

  • Energy cost: 28.8 $ / unit (headline result)
  • Energy used: 240 kWh
  • Cost per piece: 0.03 $ / piece
  • Hourly cost: 3.6 $ / hr

Run it with your numbers

  • Every input above is editable in the live Energy Per Cycle calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.