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Plant Engineering Calculator

Boiler Economizer Savings Calculator — Flue Heat Recovery & Fuel Savings

Estimate recoverable economizer duty, equivalent fuel input reduction and annual fuel-cost savings from feedwater temperature rise.

Inputs

Results

Recovered duty 581.4 kW
Equivalent fuel input 684.0 kW
Annual fuel energy 4103.9 MWh
Annual fuel savings $143637

Formula

Q=mfw·Cp·ΔT/3600; fuel saved=Q/η.

Worked example

20,000 kg/h feedwater heated by 25 K at Cp=4.186 recovers about 581 kW before boiler-efficiency conversion.

Assumptions & limits

  • Uses sensible feedwater heating only.
  • Verify stack-temperature, corrosion/dew-point and economizer pressure-drop limits.

FAQs

What does this Boiler Economizer Savings Calculator calculate?

Estimate recoverable economizer duty, equivalent fuel input reduction and annual fuel-cost savings from feedwater temperature rise.

Which inputs matter most?

Use measured operating data where possible and keep pressure, temperature, flow, efficiency and tariff inputs on the stated basis. Intermediate outputs make the calculation auditable.

Can I use this for final equipment selection?

Use it for engineering screening and scenario comparison. Confirm final selections against OEM curves, steam/property tables, applicable codes and project design conditions.

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boiler feedwater heating dutyboiler stack lossboiler efficiency

Last updated: 2026-09-17