1. What is Cooling Tower Sizing Rule of Thumb?

Definition: This calculator estimates the heat load capacity needed for a cooling tower based on water flow rate and temperature difference.

Purpose: It helps HVAC engineers and facility managers determine appropriate cooling tower sizing for heat rejection requirements.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Heat load (BTU/hour)
• \( GPM \) — Water flow rate (gallons per minute)
• \( \Delta T \) — Temperature difference (°F)
• 500 — Constant representing the weight of water (8.33 lb/gal) × 60 min/hour × specific heat (1 BTU/lb-°F)

Explanation: The formula calculates the heat removed from water as it passes through the cooling tower.

3. Importance of Proper Cooling Tower Sizing

Details: Correct sizing ensures efficient heat rejection, prevents system overload, and maintains optimal equipment performance.

4. Using the Calculator

Tips: Enter the water flow rate in GPM and temperature difference in °F between entering and leaving water. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why is the constant 500 used in the formula?
A: It combines the weight of water (8.33 lb/gal), time conversion (60 min/hour), and water's specific heat (1 BTU/lb-°F) into one constant.

Q2: What's a typical temperature difference (ΔT) for cooling towers?
A: Most cooling towers operate with ΔT between 10-30°F, depending on design and application.

Q3: How does this relate to cooling tower tonnage?
A: 1 cooling tower ton = 15,000 BTU/h. Divide the result by 15,000 to estimate required tonnage.

Q4: Does this account for approach temperature?
A: No, this is a basic rule of thumb. Actual sizing requires considering approach to wet bulb temperature.

Q5: What if I have the heat load in tons?
A: Multiply tons by 15,000 to get BTU/h, or use this calculator in reverse by entering known values.