Sensible Cooling Load due to infiltrating air Calculator

Sensible Cooling Load Formula:

\[ Q_{ph} = 1.1 \times CFM \times \Delta T \]

Sensible Cooling Load (BTU/hr):

1. What is Sensible Cooling Load due to infiltrating air?

Definition: This is the heat added to a conditioned space by means of air infiltration through cracks, openings, or ventilation.

Purpose: It helps HVAC professionals determine the cooling capacity needed to maintain comfortable indoor temperatures.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ Q_{ph} = 1.1 \times CFM \times \Delta T \]

Where:

\( Q_{ph} \) — Sensible cooling load (BTU/hr)
\( CFM \) — Air infiltration rate (cubic feet per minute)
\( \Delta T \) — Temperature difference between outdoor and indoor air (°F)
1.1 — Constant combining air density and specific heat

Explanation: The formula calculates the heat energy that must be removed to maintain the desired indoor temperature.

3. Importance of Sensible Cooling Load Calculation

Details: Proper calculation ensures HVAC systems are properly sized for energy efficiency and comfort.

4. Using the Calculator

Tips: Enter the air infiltration rate in CFM and temperature difference in °F. Both values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical CFM value for infiltration?
A: It varies by building tightness, but 0.5-1.5 CFM per square foot is common for older buildings.

Q2: Why is there a ±5% tolerance?
A: Air infiltration rates are estimates and can vary based on wind, building pressure, and other factors.

Q3: How do I measure air infiltration rate?
A: Professional blower door tests provide the most accurate measurements.

Q4: What's included in sensible cooling load?
A: Only temperature-related heat transfer, not latent (moisture) loads.

Q5: How does this differ from ventilation load?
A: Infiltration is uncontrolled air leakage, while ventilation is intentional outdoor air introduction.