Pipe Heat Loss Calculator

1. Installation & Environment

Environment

Ambient Temp

°C

Wind Speed (v)

m/s

Advanced Environment Settings (ε)

Outer Surface Emissivity (ε)

—

Typical: aluminum jacketing 0.05–0.2; painted steel 0.8–0.95.

2. Process Fluid

Fluid Preset

Inlet Pressure

kPag

Inlet Temp

°C

Mass Flow

kg/h

Fluid Properties (Density, Cp, k, µ)

Density (ρ)

kg/m³

Spec. Heat (Cp)

kJ/kgK

Therm. Cond (k)

W/mK

Viscosity (μ)

3. Pipe Geometry

Material

Size

Schedule

Pipe Length

4. Insulation System

Material

Thickness

Thermal Performance Results

        Total Heat Loss (Q):
        --
      

        Outlet Temperature:
        --
      

        Surface Temperature:
        --
      

Heat Transfer Analysis

Linear Heat Loss:--

Heat Flux (Surface):--

Overall U-Value (OD):--

Insulation Efficiency:--

Hydraulic Analysis

Flow Regime:--

Reynolds Number:--

Velocity:--

Pressure Drop:--

Temperature Profile

Inlet (0m) Length (L) Outlet

Technical Notes

Variable Definitions

T_in, T_out: inlet and outlet bulk fluid temperatures (°C).
T_amb: ambient air/soil temperature (°C).
Q: total heat loss over length L (W).
q′: linear heat loss (W/m).
q″: surface heat flux based on outer diameter (W/m²).
U_o: overall heat transfer coefficient based on pipe OD area (W/m²·K).
h_i: internal convection coefficient (W/m²·K).
h_conv, h_rad: external convection and radiation coefficients (W/m²·K).
R: thermal resistances per meter (K/W·m) combined in series.
Re, Pr: Reynolds and Prandtl numbers (dimensionless).
f: Darcy friction factor (dimensionless); ΔP: pressure drop (kPa).

Formulas / Logic

Overall resistance (per meter): R = R_i + R_wall + R_ins + R_o
Internal convection: Nu via laminar developing (Hausen-type) and Gnielinski for turbulent; h_i=Nu·k/D.
External forced convection (air): Churchill–Bernstein correlation for cylinder crossflow.
External natural convection (air): Churchill–Chu (horizontal cylinder) when wind is low.
Radiation (linearized): h_rad=εσ(T_s²+T_a²)(T_s+T_a).
Buried case (soil conduction): R_soil=ln(2H/r)/(2πk_soil) (depth to center H, radius r).
Outlet temperature (energy balance): T_out=T_amb+(T_in-T_amb)·exp(-UA/(ṁC_p)).
Pressure drop: ΔP=f(L/D)·(ρv²/2), with f from Churchill correlation (laminar 64/Re).

The tool iterates to find a consistent outer surface temperature because h_conv and h_rad depend on film and surface temperature.

Assumptions / Notes

Screening-level steady-state model with constant properties (use best-estimate properties at mean temperature for improved accuracy).
Gas density is estimated by ideal gas law using inlet P and T (compressibility not included).
Buried model uses a simplified conduction shape factor; does not include soil moisture change, groundwater, or thermal contact resistance.
For personnel protection, common practice limits surface temperature (e.g., 60°C touch-safe screening) — confirm project criteria.

Standards / References

ASTM C680 (thermal analysis for insulation systems) and common industrial practice.
Crane TP-410 and standard heat transfer correlations (Churchill–Bernstein; Churchill–Chu; Gnielinski).
Pipe dimensions are based on embedded subsets of ASME B36.10/B36.19 dimensional data.

Pipe Heat Loss Calculator | ASTM C680 & Crane TP-410