Use this engineering calculation for a transparent preliminary estimate or independent arithmetic check when geometry, materials, loads, operating conditions, and units are defined consistently.

Number Of Transfer Units

Required number input.

Capacity Rate Ratio

Required number input.

Parallel-flow heat-exchanger effectiveness ε=[1−exp(−NTU(1+Cr))]/(1+Cr) for capacity-rate ratio Cr in [0,1]. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Effectiveness

The resulting effectiveness returned as a number.

• Heat-transfer estimates depend on geometry, contact resistances, radiation, convection regime, temperature-dependent properties, fouling, phase change, and boundary conditions. Tabulated coefficients and COP values are operating-condition specific.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check assumptions against drawings, measurements, current material data, and the applicable design code. Apply required load combinations and safety factors, then obtain qualified review and testing for consequential designs.

• Convective Heat Transfer

  Newton-law convection heat-transfer rate hAΔT with a supplied convection coefficient at the stated flow condition.

• Otto Cycle Efficiency

  Ideal air-standard Otto-cycle thermal efficiency 1−1/r^(γ−1) from compression ratio and constant heat-capacity ratio.

• Thermal Resistance Series

  Total thermal resistance of two one-dimensional heat-flow layers connected in series at the same heat rate.