1. What Is Pressure Tank Capacity?

Pressure tank capacity refers to the volume of water a pressure tank can hold and deliver between pump cycles. It's a critical parameter in water supply systems that helps maintain consistent water pressure and reduces pump cycling frequency.

2. How Does The Calculator Work?

The calculator uses the pressure tank capacity formula:

Where:

• \( V \) — Pressure tank capacity (m³)
• Pump Output — Water flow rate from the pump (m³/s)
• Runtime — Duration of pump operation (seconds)
• Drawdown Fraction — Ratio of usable water to total tank capacity (dimensionless)

Explanation: This formula calculates the required tank capacity based on the pump's output, how long it runs, and what fraction of the tank's total volume is actually usable water.

3. Importance Of Pressure Tank Capacity Calculation

Details: Proper pressure tank sizing is essential for efficient water system operation. An appropriately sized tank reduces pump cycling, conserves energy, extends equipment life, and maintains consistent water pressure throughout the system.

4. Using The Calculator

Tips: Enter pump output in m³/s, runtime in seconds, and drawdown fraction as a dimensionless value. All values must be positive numbers greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical drawdown fraction value?
A: Drawdown fraction typically ranges from 0.2 to 0.4 (20-40%) for most pressure tanks, depending on the pre-charge pressure and cut-in/cut-out pressure settings.

Q2: How does pump output affect tank size?
A: Higher pump output requires a larger tank capacity to achieve the same runtime and reduce cycling frequency.

Q3: What happens if the tank is undersized?
A: An undersized tank causes frequent pump cycling, leading to increased energy consumption, reduced pump life, and potential pressure fluctuations.

Q4: Can this formula be used for all types of pressure tanks?
A: This formula provides a general calculation for pressure tank capacity. Specific tank types (bladder, diaphragm, conventional) may have additional considerations.

Q5: How often should pressure tank capacity be recalculated?
A: Recalculate when changing pump size, modifying water demand, or if experiencing pressure or cycling issues in the system.