Cooling Coil Size Calculator

Cooling Coil Capacity Formula:

\[ Capacity (tons) = \frac{CFM \times \Delta T \times 1.08}{12,000} \]

Capacity (tons):

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1. What is Cooling Coil Sizing?

Cooling coil sizing is the process of determining the appropriate capacity of a cooling coil based on airflow and temperature difference. Proper sizing ensures efficient operation and optimal performance of HVAC systems.

2. How Does the Calculator Work?

The calculator uses the cooling capacity formula:

\[ Capacity (tons) = \frac{CFM \times \Delta T \times 1.08}{12,000} \]

Where:

\( CFM \) — Airflow rate in cubic feet per minute
\( \Delta T \) — Temperature difference across the coil in °F
\( 1.08 \) — Constant for air at standard conditions
\( 12,000 \) — Conversion factor (BTU/hr to tons)

Explanation: This formula calculates the cooling capacity in tons based on the sensible heat removal from the air stream.

3. Importance of Proper Coil Sizing

Details: Proper coil sizing is critical for energy efficiency, comfort control, and system longevity. Undersized coils cannot meet cooling demands, while oversized coils cause short cycling and humidity issues.

4. Using the Calculator

Tips: Enter CFM (airflow rate) and ΔT (temperature drop across the coil). Both values must be positive numbers for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is the 1.08 constant in the formula?
A: The 1.08 constant represents the product of air density (0.075 lb/ft³) and specific heat (0.24 BTU/lb·°F) multiplied by 60 minutes/hour.

Q2: What is a typical ΔT for cooling coils?
A: Typical ΔT values range from 15°F to 25°F for standard comfort cooling applications, depending on system design and humidity requirements.

Q3: How does humidity affect coil sizing?
A: This formula calculates sensible cooling only. For total cooling capacity (sensible + latent), additional calculations for latent heat removal are needed.

Q4: What are common CFM ranges for different applications?
A: Residential systems: 400-2000 CFM, Commercial systems: 2000-20,000+ CFM, depending on building size and occupancy.

Q5: When should professional engineering be consulted?
A: For complex systems, critical environments, or when latent load calculations are required, consult with a professional mechanical engineer.