Energy
Boiler Blowdown Heat Recovery Calculator
Estimate recoverable heat, avoided fuel energy and annual cost savings from boiler blowdown heat recovery.
Fraction of available blowdown sensible heat effectively transferred to useful service.
Recoverable Heat
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Estimated useful heat recoverable from boiler blowdown.
Available blowdown heat
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Recoverable heat
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Annual useful heat recovered
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Avoided fuel energy
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Annual cost savings
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Temperature difference
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Annual blowdown quantity
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Method:
Available sensible heat in blowdown is estimated as:
Qavailable =
ṁ × cp ×
(Tblowdown − Tmakeup)
using a water specific heat capacity of approximately 4.186 kJ/kg·K.
Recoverable heat is:
Qrecovered =
Qavailable × Heat Recovery Efficiency
Annual useful heat recovered is:
Energy Recovered =
Qrecovered × Operating Hours
Avoided boiler fuel energy is estimated as:
Avoided Fuel Energy =
Energy Recovered ÷ Boiler Efficiency
Annual cost savings are:
Cost Savings =
Avoided Fuel Energy × Fuel Energy Cost
This calculator uses a simplified sensible-heat approach. Actual high-pressure boiler blowdown may flash when pressure is reduced, so a flash tank and heat-recovery exchanger can involve both flash-steam recovery and remaining liquid sensible heat.
For detailed steam-system analysis, use pressure-specific steam and water enthalpy values rather than only temperature-based sensible heat.
