When is NTU method preferred over LMTD?

NTU method is preferred when outlet temperatures are unknown (sizing problems). LMTD is easier when all temperatures are known (rating problems). Both give the same results when converged.

What is the capacity ratio C*?

C* = C_min/C_max (ratio of heat capacity rates). C* = 0 for condensers/evaporators (one fluid at constant T). C* = 1 for balanced flow. For C* = 0: ε = 1 - e^(-NTU) for all configurations.

What NTU is typical for industrial heat exchangers?

NTU typically 1-5. Low NTU = low effectiveness but low pressure drop. NTU > 5 gives diminishing returns on effectiveness. Most cost-effective designs aim for NTU = 2-3 with ε = 70-85%.

NTU-Effectiveness Heat Exchanger Calculator

Calculate heat exchanger effectiveness ε = Q/Q_max using NTU method. NTU = U·A/C_min. Effectiveness-NTU relations for parallel flow, counterflow, shell-tube 1-2 pass, and cross-flow configurations.

2D stress state at a point. All stresses in MPa.

σx — Normal Stress X (MPa)

σy — Normal Stress Y (MPa)

τxy — Shear Stress (MPa)

⚙ Mechanical Note: Results are based on standard textbook formulas and ISO/AASHTO references. Always verify critical designs with applicable codes (ISO 898, AASHTO 1993, AISC, Eurocode 3) and a qualified engineer.

How It Works

Calculate heat exchanger effectiveness ε = Q/Q_max using NTU method. NTU = U·A/C_min. Effectiveness-NTU relations for parallel flow, counterflow, shell-tube 1-2 pass, and cross-flow configurations

Each component has a specific meaning:

NTU method — The ntu method recorded for the patient or scenario being assessed.

Note: Interpret the ntu-effectiveness result against the clinical thresholds and context described above.

How to Use

Enter the NTU method for the patient or scenario you are assessing. Calculate heat exchanger effectiveness ε = Q/Q_max using NTU method. NTU = U·A/C_min. Effectiveness-NTU relations for parallel flow, counterflow, shell-tube 1-2 pass, and cross-flow configurations. Use the ntu-effectiveness result to inform your clinical assessment.

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NTU-Effectiveness Heat Exchanger Calculator

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Frequently Asked Questions

When is NTU method preferred over LMTD?

What is the capacity ratio C*?

What NTU is typical for industrial heat exchangers?