Cooling Tower Commercial Building

Heat Rejection Formula:

\[ Q = m \times c \times \Delta T + Q_{latent} \]

Water Mass Flow Rate:

Specific Heat Capacity:

BTU/lb·°F

Temperature Difference:

°F

Latent Heat:

BTU

Total Heat Rejection (BTU):

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1. What is Cooling Tower Heat Rejection?

Definition: This calculator estimates the total heat rejection in a cooling tower system for commercial buildings, considering both sensible and latent heat components.

Purpose: It helps HVAC engineers and facility managers determine the cooling capacity required for commercial building cooling tower systems.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ Q = m \times c \times \Delta T + Q_{latent} \]

Where:

\( Q \) — Total heat rejection (BTU)
\( m \) — Water mass flow rate (lb)
\( c \) — Specific heat capacity of water (BTU/lb·°F)
\( \Delta T \) — Temperature difference (°F)
\( Q_{latent} \) — Latent heat from evaporation (BTU)

Explanation: The formula calculates sensible heat (from temperature change) plus latent heat (from phase change) to determine total heat rejection.

3. Importance of Heat Rejection Calculation

Details: Accurate heat rejection calculations ensure proper cooling tower sizing, energy efficiency, and reliable operation of HVAC systems in commercial buildings.

4. Using the Calculator

Tips: Enter water mass flow rate, specific heat capacity (default 1.0 BTU/lb·°F for water), temperature difference, and latent heat (if applicable). All values must be ≥ 0.

5. Frequently Asked Questions (FAQ)

Q1: What's the typical temperature difference in cooling towers?
A: Most commercial cooling towers operate with a 10-20°F temperature difference between incoming and outgoing water.

Q2: When is latent heat significant?
A: Latent heat becomes important in evaporative cooling towers where water evaporation contributes significantly to heat rejection.

Q3: How do I find the water mass flow rate?
A: Measure flow rate in GPM and multiply by 8.33 lb/gal (for water at 60°F) to get lb/min, then multiply by 60 for lb/hr.

Q4: What's the range for specific heat capacity?
A: For water, it's typically 1.0 BTU/lb·°F, but can vary slightly with temperature (0.998 at 68°F to 1.003 at 212°F).

Q5: How does this relate to cooling tower tonnage?
A: 1 cooling ton = 12,000 BTU/hr. Divide total heat rejection by 12,000 to estimate required cooling tower capacity in tons.