1. What is Relative Heat Gain (RHG)?

Definition: Relative Heat Gain measures the amount of heat energy gained per unit area of a surface.

Purpose: It helps engineers and architects evaluate thermal performance of building materials and systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( RHG \) — Relative heat gain (Watts per square meter, W/m²)
• \( Q \) — Total heat gain (Watts, W)
• \( A \) — Surface area (square meters, m²)

Explanation: The total heat gain is divided by the surface area to determine the heat gain intensity per unit area.

3. Importance of Relative Heat Gain Calculation

Details: Calculating RHG helps in designing energy-efficient buildings, selecting appropriate insulation materials, and optimizing HVAC systems.

4. Using the Calculator

Tips: Enter the total heat gain in Watts and the surface area in square meters. Both values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical RHG value for windows?
A: Standard double-glazed windows typically have RHG values between 100-300 W/m² depending on glass type and coatings.

Q2: How does RHG differ from U-factor?
A: U-factor measures heat transfer rate, while RHG measures actual heat gain per unit area including solar effects.

Q3: When would I need to calculate RHG?
A: When designing building envelopes, selecting window systems, or evaluating thermal performance of materials.

Q4: How do I find total heat gain (Q)?
A: Q can be calculated using heat transfer equations or measured with thermal sensors in real-world applications.

Q5: Does RHG account for time?
A: No, RHG is an instantaneous measurement. For time-based analysis, you would calculate total heat gain over time.