Plant Utilities worked example

Boiler Blowdown Loss at 72% unrecovered heat share: a worked example

Here is what the math looks like when conditions slip. We hold every other input steady and drop unrecovered heat share to 72%, then walk the calculation through step by step. Estimate boiler blowdown loss from hot water, chemicals, heat, and makeup water that leave the boiler system.

The inputs for this scenario

  • Boiler blowdown volume: 420 klb (held at the documented default)
  • Fuel and water value per klb: 5.6 $ / klb (held at the documented default)
  • Unrecovered heat share: 72 % (the input this scenario stresses; the baseline uses 100)
  • Testing and treatment adder: 150 $ (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Total boiler blowdown loss cost = boiler blowdown volume × fuel and water value lost × unrecovered heat share + testing and treatment adder.
  • Total boiler blowdown loss cost works out to 1,843 $ at these inputs, and this is the headline figure for the scenario.
  • Cost per item or period works out to 4.39 $ / item at these inputs.
  • Variable boiler blowdown loss cost works out to 1,693 $ at these inputs.
  • Fixed utility adder works out to 150 $ at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where unrecovered heat share sits at 100% and the headline result is 2,502 $, this scenario comes in 26.32% below the baseline at 1,843 $.
  • The practical read: the gap between this scenario and the baseline is entirely attributable to unrecovered heat share, so recovering it is worth quantifying in dollars before considering equipment or staffing changes. It uses a single blended value per klb; actual fuel and makeup-water costs vary with load and season, so recompute when energy prices or cycles of concentration change.

Results at a glance

  • Total boiler blowdown loss cost: 1,843 $ (headline result)
  • Cost per item or period: 4.39 $ / item
  • Variable boiler blowdown loss cost: 1,693 $
  • Fixed utility adder: 150 $

Run it with your numbers

  • To rerun this with your own numbers, open the live Boiler Blowdown Loss calculator, set unrecovered heat share to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.