Skip to content
Open calculators

Cooling Flow and Channel Diameter Estimate

Estimate coolant flow and an equivalent channel diameter from heat load, fluid properties, and target velocity.

Example starting values are prefilled to demonstrate the calculation. Replace them with your measured, quoted, or job-specific inputs before relying on a result.

Inputs

Inputs

Range: at least 0.001 BTU/h

Enter the heat load assigned to the circuit being sized. For multiple parallel circuits, use the heat/flow allocation for one circuit or size each circuit separately.

Range: at least 0.001

Use a value for the actual coolant mixture and operating temperature; do not assume pure water for glycol blends.

Range: at least 0.001 F

Enter the expected coolant outlet minus inlet temperature for the circuit, in °F.

Range: at least 0.001 lb/US gal

Use coolant density at the relevant operating temperature in pounds per US gallon.

Range: at least 0.001 ft/s

Enter a design velocity selected for the coolant, channel, and circuit. The calculator does not recommend a universal velocity or check pressure loss/turbulence.

Result

Equivalent channel inside diameter (mm)
20.53
Required coolant mass flow (lb/h)
2,400.00
Equivalent channel inside diameter (in)
0.808
Required coolant volume flow (US gal/min)
4.80
Heat-balance assumptions and limits
Mass flow follows a steady heat balance using the entered coolant heat capacity and temperature rise. The diameter is an equivalent circular inside diameter for the entered total flow and selected velocity, assuming the flow passes through one circuit. It does not split heat/flow among parallel circuits, calculate pressure drop, pump capacity, Reynolds number, or chiller capacity; validate coolant properties and circuit design separately.

Related calculators