Heat Exchanger Sizing

mechanical

Sizes a heat exchanger using LMTD or NTU-effectiveness method. Pulls fluid properties (cp, density, viscosity) from reference tables at operating temperatures. Estimates overall U from Perry's Table 11-3 fluid-pair data and fouling factors from TEMA RGP-T-2.

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Method

Sizing method. LMTD is standard when all four terminal temperatures are known or can be determined. NTU-effectiveness is preferred when outlet temperatures are unknown and you are sizing for a target effectiveness. If omitted, defaults to LMTD.

Hot Fluid*

Hot-side fluid name matching the fluid-properties reference table (e.g. 'water', 'ethylene_glycol_50', 'therminol_vp1'). Used to look up cp, density, viscosity, and conductivity at the average hot-side temperature.

Hot Inlet C*

Hot fluid inlet temperature in degrees Celsius. Must be higher than hot_outlet_C. Typical: 80-150 C for process heat recovery, 30-50 C for HVAC.

Hot Outlet C*

Hot fluid outlet (target) temperature in degrees Celsius. Must be lower than hot_inlet_C. Must be > cold_inlet_C to maintain positive LMTD.

Hot Flow Rate Kg S*

Hot-side mass flow rate. Typical: 0.1-10 kg/s for process exchangers, 0.01-0.5 kg/s for HVAC coils.

Cold Fluid*

Cold-side fluid name matching the fluid-properties reference table (e.g. 'water', 'air'). Used to look up cp, density, viscosity, and conductivity at the average cold-side temperature.

Cold Inlet C*

Cold fluid inlet temperature in degrees Celsius. Typical: 5-15 C for chilled water, 15-25 C for cooling water.

Cold Outlet C

Cold fluid outlet temperature in degrees Celsius. Provide either this or cold_flow_rate_kg_s; the other will be calculated from energy balance.

Cold Flow Rate Kg S

Cold-side mass flow rate. Provide either this or cold_outlet_C; the other will be calculated from energy balance.

Flow Arrangement

Flow arrangement geometry. Counterflow gives highest LMTD for a given duty. Shell-and-tube applies an F correction factor per TEMA standards. Affects both LMTD correction and NTU-effectiveness relations. If omitted, defaults to counterflow.

U Override W M2K

Override for overall heat transfer coefficient. If omitted, U is estimated from Perry's Table 11-3 based on the hot/cold fluid pair. Typical: 300-1000 W/m2K for liquid-liquid, 20-70 W/m2K for gas-liquid.

Fouling Factor Override M2K W

Total fouling resistance override (hot + cold sides combined). If omitted, fouling factors are looked up per TEMA RGP-T-2 for each fluid. Typical: 0.0001-0.0005 m2K/W for clean services, 0.001+ for dirty or scaling fluids.

Reference data

This calculator pulls live values from the following engineering reference tables in the database.

fluid properties

About this calculator

Heat Exchanger Sizing is part of the Engineering Database calculator suite. Each tool runs deterministic calculations against authoritative reference data and code-compliant methods, so results are reproducible and traceable to source standards.

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Reference data

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