Gpm Per Ton Calculator

A GPM per Ton calculator is a tool used in HVAC and cooling system design. It helps engineers, technicians, and system designers determine the required water flow rate for a given cooling capacity. Since water is used as a medium to absorb and transfer heat, calculating the correct gallons per minute (GPM) ensures the system operates efficiently. This calculator is especially important for chillers, cooling towers, and hydronic systems.

This calculator belongs to the HVAC and mechanical engineering calculators category. It simplifies system design by providing quick conversions between flow rate, cooling load, and temperature difference.

formula

Primary Formula: Calculating Total GPM

This formula finds the total water flow rate needed for a given tonnage and temperature difference.

Formula:
GPM = (Tons * 24) / ΔT

Variable Definitions:
GPM: Total required water flow in Gallons Per Minute
Tons: Cooling load in Tons of Refrigeration
ΔT: Temperature difference (in °F) between water entering and leaving the chiller
24: Constant derived from water properties and refrigeration definition

Formula for GPM per Ton Ratio

This formula calculates the required gallons per minute for each ton of cooling.

Formula:
GPM per Ton = 24 / ΔT

Variable Definitions:
GPM per Ton: Flow per ton of cooling capacity
ΔT: Temperature difference in °F
24: Constant

Example: For ΔT = 10°F, GPM per Ton = 24 / 10 = 2.4 GPM per Ton.

Supporting Formulas

Calculating Tons of Refrigeration

Tons = (GPM * ΔT) / 24

Calculating Temperature Difference (ΔT)

ΔT = (Tons * 24) / GPM

These supporting formulas allow you to solve for tonnage or temperature difference when GPM is known.

General Reference Table

This table shows common values of GPM per Ton based on different temperature differences.

This table helps quickly estimate flow requirements during HVAC design and troubleshooting.

Example

Suppose you are designing a cooling system with a load of 150 tons and a temperature difference of 12°F.

Formula:

GPM = (Tons * 24) / ΔT

GPM = (150 * 24) / 12
GPM = 3600 / 12
GPM = 300

So, the required flow rate is 300 gallons per minute.

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