Calculator Inputs
Performance Graph
The chart compares key design outputs after each calculation.
Example Data Table
| Case | Hot In / Out (°C) | Cold In / Out (°C) | Hot Flow (kg/h) | Cold Flow (kg/h) | U Clean (W/m²·K) | Tube OD / ID (mm) | Tube Length (m) |
|---|---|---|---|---|---|---|---|
| Base Example | 160 / 110 | 30 / 75 | 18,000 | 22,000 | 650 | 19.05 / 16.0 | 4.88 |
| Higher Duty | 190 / 120 | 35 / 95 | 24,500 | 26,800 | 720 | 25.4 / 21.2 | 6.10 |
| Compact Case | 135 / 92 | 25 / 62 | 11,500 | 14,000 | 540 | 15.88 / 12.7 | 3.66 |
Formula Used
Hot side duty: Qhot = ṁhot × Cp,hot × (Th,in − Th,out)
Cold side duty: Qcold = ṁcold × Cp,cold × (Tc,out − Tc,in)
Adopted duty: Qavg = (Qhot + Qcold) / 2
Log mean temperature difference: LMTD = (ΔT1 − ΔT2) / ln(ΔT1/ΔT2)
Corrected temperature difference: ΔTcorrected = F × LMTD
Effective overall coefficient: Ueffective = 1 / (1/Uclean + Rf)
Required area: A = Qdesign / (Ueffective × ΔTcorrected)
Tube area per tube: Atube = π × do × L
Estimated tube count: N = A / Atube
Tube-side velocity: v = volumetric flow / available flow area
Tube-side Reynolds number: Re = ρ × v × di / μ
This page gives a practical first-pass design estimate. Final mechanical design should still be checked against project codes, allowable pressure drop, vibration limits, and detailed rating software.
How to Use This Calculator
- Choose the flow arrangement and select which fluid runs through the tubes.
- Enter hot-side and cold-side mass flow, Cp, density, viscosity, and inlet and outlet temperatures.
- Enter the clean overall coefficient, fouling factor, correction factor, and design margin.
- Provide tube geometry, tube passes, shell passes, and tube pitch.
- Click Calculate Exchanger to show the results above the form.
- Review duty balance, area, tube count, velocity, Reynolds number, and bundle diameter estimate.
- Use the graph for quick comparison and export the result summary to CSV or PDF.
- Adjust inputs until your trial design reaches a realistic thermal and hydraulic range.
Frequently Asked Questions
1. What does this calculator estimate?
It estimates heat duty, LMTD, corrected driving force, required heat transfer area, approximate tube count, tube-side velocity, Reynolds number, bundle diameter, and oversurface.
2. Why are both hot-side and cold-side duties shown?
Real input data often contains rounding or measurement differences. Showing both duties helps you spot imbalance and decide whether temperatures, flows, or Cp values need review.
3. What is the correction factor F used for?
Shell-and-tube exchangers rarely behave like perfect counterflow units. F corrects the ideal LMTD to reflect the actual pass arrangement and thermal mixing pattern.
4. Does this replace detailed exchanger rating software?
No. It is best for preliminary sizing and engineering checks. Final design still needs pressure-drop review, mechanical verification, allowable stress checks, and code compliance.
5. Why is fouling factor included?
Fouling adds thermal resistance. Including it lowers the effective overall coefficient, which usually increases required area and gives a more realistic service estimate.
6. How is tube-side velocity determined?
The calculator uses the selected tube-side fluid, its density, flow rate, inner tube diameter, and the number of tubes active per pass to estimate average velocity.
7. What Reynolds number range is acceptable?
That depends on fluid properties, fouling risk, erosion limits, and pressure-drop allowance. In many liquid services, designers often prefer turbulent flow for better heat transfer.
8. Can I use this for condensers or reboilers?
Only as a rough screening tool. Phase-change services need dedicated correlations and more detailed treatment than this single-phase preliminary calculator provides.