1. What is a Steam Boiler Sizing Calculator?

Definition: This calculator estimates the capacity of a steam boiler in pounds per hour based on the heat load and latent heat of vaporization.

Purpose: It helps engineers and HVAC professionals properly size steam boilers for heating systems and industrial processes.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• Capacity — Boiler capacity (pounds per hour)
• Load BTU/h — Heat load (British Thermal Units per hour)
• \( h_{fg} \) — Latent heat of vaporization (BTU per pound)

Explanation: The heat load is divided by the latent heat to determine how much steam the boiler needs to produce to meet the demand.

3. Importance of Proper Boiler Sizing

Details: Correct boiler sizing ensures efficient operation, prevents energy waste, and maintains system reliability. Oversized boilers cycle too frequently, while undersized ones can't meet demand.

4. Using the Calculator

Tips: Enter the heat load in BTU/h and latent heat (default 970.3 BTU/lb for water at atmospheric pressure). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is h_fg (latent heat of vaporization)?
A: The energy required to convert 1 pound of water to steam at the same temperature, typically 970.3 BTU/lb at atmospheric pressure.

Q2: How do I determine the heat load?
A: Calculate from building heat loss, process requirements, or equipment specifications. For buildings, use Manual J calculations.

Q3: Does this account for system losses?
A: No, consider adding 10-20% to the calculated capacity for piping losses, startup loads, and safety factors.

Q4: What pressure does the default h_fg value represent?
A: The default 970.3 BTU/lb is for atmospheric pressure (0 psig). Higher pressures reduce this value.

Q5: Can this be used for hot water boilers?
A: No, this calculator is specific to steam systems. Hot water boilers use different sizing methods.