Condensate Return Calculator
Quantify condensate return rate, flash steam losses, and dollar savings from returning condensate to the boiler.
Inputs
Results
Formula
Condensate = Steam × return%; Flash% = (h_f,high − h_f,low)/h_fg,low; Savings = m·ΔT·cp·hours/η_boiler × fuel_cost.
Worked example
10,000 lb/hr steam load, 70% return, 100 → 0 psig trap: condensate ≈ 7,000 lb/hr, flash ≈ 6.5% (455 lb/hr), net return ≈ 6,545 lb/hr. Energy retained ≈ 916 kBtu/hr → about $53k/yr at $8/MMBtu.
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Frequently asked questions
Why does high-pressure condensate flash?
Condensate is saturated liquid at trap upstream pressure. When it enters a lower-pressure return line, some of it must instantly boil to reach the new saturation temperature — this is flash steam.
How can I recover flash steam?
Route the return header to a flash tank feeding a low-pressure header (space heating, deaerator sparge). It's typically one of the highest-ROI steam-side improvements.
Is 70% return realistic?
Process plants often see 40–70%; heating-only systems can exceed 90%. Below 50% usually means a trap survey is overdue.
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