Chilled Water Flow Calculation Formula

Chilled Water Flow Formula:

\[ Flow (GPM) = \frac{Tons \times 24}{\Delta T} \]

Flow (GPM):

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1. What is the Chilled Water Flow Calculation Formula?

The Chilled Water Flow Calculation Formula is used to determine the flow rate of chilled water required in HVAC systems based on the cooling load in tons and the temperature difference across the system.

2. How Does the Calculator Work?

The calculator uses the chilled water flow formula:

\[ Flow (GPM) = \frac{Tons \times 24}{\Delta T} \]

Where:

\( Flow \) — Chilled water flow rate in gallons per minute (GPM)
\( Tons \) — Cooling load in refrigeration tons
\( \Delta T \) — Temperature difference across the system in degrees Fahrenheit (°F)

Explanation: The formula calculates the required water flow rate to achieve the desired cooling capacity, with 24 representing the constant conversion factor between tons and BTU/hour.

3. Importance of Flow Calculation

Details: Accurate flow calculation is essential for proper HVAC system design, pump selection, energy efficiency optimization, and ensuring adequate heat transfer in chilled water systems.

4. Using the Calculator

Tips: Enter the cooling load in tons and the temperature difference in °F. Both values must be positive numbers greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical ΔT for chilled water systems?
A: Typical ΔT values range from 10°F to 20°F, with 12°F being common in many commercial HVAC systems.

Q2: Why is 24 used in the formula?
A: 24 represents the conversion factor since 1 ton of refrigeration = 12,000 BTU/hour and 1 GPM of water with 1°F ΔT transfers 500 BTU/hour.

Q3: Can this formula be used for other fluids?
A: This specific formula is designed for water. For other fluids, additional factors like specific heat and density must be considered.

Q4: What affects the ΔT in a system?
A: ΔT is affected by heat exchanger efficiency, flow rate, cooling load, and system design parameters.

Q5: How does flow rate impact system performance?
A: Proper flow rate ensures efficient heat transfer, while insufficient flow can lead to poor cooling and excessive flow can increase pumping costs.