Heat Exchanger Sizing Calculator
Estimate heat duty, LMTD, and required area for sensible & latent heat
This calculator estimates heat duty, logarithmic mean temperature difference (LMTD), and required heat transfer area. Select whether the heating medium uses sensible heat (hot water/thermal oil) or latent heat (saturated steam condensation).
Ensure counter-current flow temperature constraints are respected (hot temperatures strictly higher than cold temperatures). Decimal values may be entered with either a dot or a comma.
Results
| Parameter | Value |
|---|
Heat duty from cold stream:
Logarithmic Mean Temperature Difference (LMTD):
Required heat transfer area:
This calculator provides a preliminary engineering estimate based on steady-state counter-current conditions and constant overall heat transfer coefficients.
Fluid Compatibility & Metallurgy: Always verify chemical and material compatibility (e.g., resistance of alloys against corrosive process fluids or chloride stress corrosion) prior to final specification.
Overpressure Protection (PSV): Ensure adequate safety valve (PSV) or thermal relief protection is installed on any isolated fluid volume or service line prone to liquid expansion or sudden vaporization (*blocked-in conditions*).
COI & HPAPI Handling: For critical streams, High Potent Active Pharmaceutical Ingredients (HPAPI), or cross-contamination risks (COI), evaluate double-wall tubes or specialized containment configurations. Vertical orientation is strongly recommended to ensure complete gravity drainage and prevent holdup, dead-legs, or cleaning/sanitization issues.
© ChemEngZone. All rights reserved. Unauthorized reproduction or distribution is prohibited.
Share your feedback
Comments and suggestions are always welcome.
Useful Engineering References
Heat Exchanger Design & Selection Guide (Alfa Laval)
Industrial overview of heat transfer fundamentals, plate and tubular heat exchanger sizing, and hygienic design standards.
Heat Exchanger Sizing – LMTD & Heat Transfer Coefficients
Technical explanation of thermal duty calculations, logarithmic mean temperature difference (LMTD), and typical U-values.
FAQ
How does this heat exchanger sizing calculator work?
This calculator estimates the heat duty, temperature driving force, and required heat transfer area in three simple steps:
Determines Thermal Duty: It calculates the total amount of thermal energy needed to heat your process fluid based on its flow rate and required temperature change. If using saturated steam, it also estimates the mass of steam required to supply that energy.
Evaluates Driving Force: It assesses the average temperature difference between the heating and cooling streams along the exchanger. For steam, it accounts for the constant condensation temperature.
Sizes the Transfer Area: Finally, by combining the required heat duty, temperature difference, and selected heat transfer efficiency coefficient, it calculates the minimum surface area needed for the equipment.
Why do I need a thermal pressure safety valve (PSV) on a heat exchanger?
If liquid gets trapped inside the shell or tube side while isolation valves are closed (a “blocked-in” scenario), continued heating from the opposite stream will cause thermal expansion or rapid vaporization. Installing a Thermal Relief Valve or Pressure Safety Valve (PSV) is mandatory to prevent dangerous overpressure and catastrophic equipment rupture.
How does fluid compatibility affect heat exchanger design?
Process fluids can cause severe corrosion, fouling, or chloride stress corrosion cracking depending on temperature and concentration. Verifying metallurgical compatibility early ensures proper selection of construction materials (such as 316L stainless steel, Hastelloy, or Titanium) to avoid premature tube failure and process contamination.
What design measures are required for HPAPI handling and Chain of Integrity (COI)?
When handling toxic chemicals, active pharmaceutical ingredients (HPAPI), or cross-contamination-sensitive streams (COI), a single-wall tube leak could contaminate the utility system. Evaluating double-wall tubes or double-tube-sheet designs provides a secondary containment barrier with early leak detection.