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Heat Transfer Calculator

Calculate process heat duty for sensible, latent, and combined phase change loads, per GPSA.

GPSAAPI
Heat Duty Calculator (GPSA/API)
Calculates sensible and latent heat duties per GPSA and API Technical Data Book correlations. Use for sizing heaters, coolers, reboilers, and condensers. Heat loss factor accounts for ambient losses (ASTM C680 basis).

Process Parameters

lb/hr

Temperature Conditions

°F
°F

Design Factors

Engineering Notes

Calculation Methods:

  • Sensible: Q = ṁ × Cp × ΔT
  • Latent: Q = ṁ × λ (Watson correlation)
  • Combined: Q₁ + Q₂ + Q₃

Design Guidelines:

  • Add 10-15% margin for exchanger fouling
  • Heat loss factor: 2-5% typical for insulated equipment
  • For fired heaters, add 15-20% for radiant/convection losses

References:

  • GPSA, Sec 23-24
  • API Technical Data Book - Petroleum Refining
  • Perry's Chemical Engineers' Handbook

Frequently Asked Questions

What does this heat duty calculator compute?

It computes process heat duty (BTU/hr): sensible heating or cooling (Q = m·Cp·ΔT), latent vaporization or condensation (Q = m·λ), and combined loads that include liquid heat-up, vaporization, and vapor superheat. It uses a temperature-corrected gas Cp and the Watson correlation for latent heat.

Does this calculator size a heat exchanger (U, area, LMTD)?

No — this tool computes the heat duty only. To size exchanger area from Q = U·A·LMTD (overall coefficient, LMTD, F-correction), use the heat exchanger sizing calculator; the duty computed here is the Q input to that step.