AHU Condensate Water Calculation Formula

AHU Condensate Formula:

\[ Condensate = CFM \times (Grains_{in} - Grains_{out}) \div 7000 \]

Condensate (pints/hr):

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1. What is the AHU Condensate Water Calculation Formula?

The AHU (Air Handling Unit) Condensate Water Calculation Formula estimates the amount of condensate water produced by an air handling unit during the dehumidification process. This calculation is essential for proper drainage system design and moisture management in HVAC systems.

2. How Does the Calculator Work?

The calculator uses the AHU condensate formula:

\[ Condensate = CFM \times (Grains_{in} - Grains_{out}) \div 7000 \]

Where:

\( CFM \) — Cubic Feet per Minute (airflow rate)
\( Grains_{in} \) — Moisture content of incoming air (grains per pound)
\( Grains_{out} \) — Moisture content of outgoing air (grains per pound)
\( 7000 \) — Conversion factor (grains per pound to pints)

Explanation: The formula calculates the amount of moisture removed from the air as it passes through the cooling coil, converting it to pints per hour for practical drainage design.

3. Importance of Condensate Calculation

Details: Accurate condensate calculation is crucial for proper drainage system sizing, preventing water damage, maintaining indoor air quality, and ensuring efficient HVAC system operation.

4. Using the Calculator

Tips: Enter CFM (airflow rate), Grains In (incoming air moisture content), and Grains Out (outgoing air moisture content). All values must be valid positive numbers, with Grains In typically greater than Grains Out for condensation to occur.

5. Frequently Asked Questions (FAQ)

Q1: What are typical grains values for indoor and outdoor air?
A: Outdoor air can range from 30-150+ grains/lb depending on climate, while supply air is typically 25-45 grains/lb after cooling.

Q2: Why is the conversion factor 7000?
A: There are 7000 grains in one pound of water, and one pound of water equals approximately one pint.

Q3: How does this affect drainage system design?
A: The calculated condensate rate determines the size of drain pipes, traps, and drainage systems needed to handle the moisture removal.

Q4: What factors can affect condensate production?
A: Air temperature, relative humidity, coil temperature, airflow rate, and system runtime all impact condensate production.

Q5: When is condensate calculation most important?
A: Critical for high-humidity environments, hospitals, laboratories, and any application where moisture control is essential.