1. What is an Air Source Heat Pump Sizing Calculator?

Definition: This calculator determines the required size (in kW) of an air source heat pump based on building heat loss and the system's coefficient of performance.

Purpose: It helps HVAC professionals and homeowners properly size heat pumps for efficient heating system design.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( kW \) — Required heat pump size (kilowatts)
• \( \text{Heat Loss} \) — Building's heat loss (kilowatts)
• \( COP \) — Coefficient of Performance (dimensionless)

Explanation: The building's heat loss is divided by the heat pump's COP to determine the minimum size needed to maintain comfortable temperatures.

3. Importance of Proper Heat Pump Sizing

Details: Correct sizing ensures energy efficiency, prevents short cycling, maintains comfort, and extends equipment lifespan.

4. Using the Calculator

Tips: Enter the building's heat loss in kW and the heat pump's COP (default 3.0). Both values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: How do I determine my building's heat loss?
A: Conduct a professional heat loss calculation or use heat loss estimation tools based on building size, insulation, and location.

Q2: What's a typical COP value?
A: Modern air source heat pumps typically have COPs between 2.5-4.0 at design conditions (colder outside temperatures).

Q3: Should I size for peak heat loss conditions?
A: Yes, the heat pump should be sized to meet the building's heat loss at the design temperature for your location.

Q4: Does this account for defrost cycles?
A: No, consider adding 10-15% capacity in very cold climates where defrost cycles are frequent.

Q5: What if my heat pump has variable capacity?
A: Variable capacity units can be sized closer to the calculated value since they can modulate output.