Rainwater Harvesting Tank Size Calculator

Rainwater Harvesting Tank Size Formula:

\[ \text{Size} = \frac{\text{Demand}}{\text{Rainfall} \times \text{Area} \times \text{Coefficient}} \]

Demand (L):

Rainfall (mm):

Area (m²):

m²

Coefficient (dimensionless):

dimensionless

Tank Size:

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1. What is the Rainwater Harvesting Tank Size Calculation?

The Rainwater Harvesting Tank Size calculation determines the appropriate storage capacity needed for rainwater collection systems based on water demand, rainfall patterns, collection area, and system efficiency coefficient.

2. How Does the Calculator Work?

The calculator uses the rainwater harvesting formula:

\[ \text{Size} = \frac{\text{Demand}}{\text{Rainfall} \times \text{Area} \times \text{Coefficient}} \]

Where:

\( \text{Demand} \) — Water demand in liters (L)
\( \text{Rainfall} \) — Rainfall amount in millimeters (mm)
\( \text{Area} \) — Collection area in square meters (m²)
\( \text{Coefficient} \) — Runoff coefficient (dimensionless, 0-1)

Explanation: The equation calculates the required tank size based on the relationship between water demand and the amount of rainwater that can be collected from a given area with a specific efficiency.

3. Importance of Tank Size Calculation

Details: Proper tank sizing is crucial for efficient rainwater harvesting systems. An appropriately sized tank ensures adequate water storage while optimizing system cost and space requirements.

4. Using the Calculator

Tips: Enter water demand in liters, rainfall in millimeters, collection area in square meters, and runoff coefficient (typically 0.6-0.9 for roof surfaces). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical runoff coefficient for roofs?
A: For most roof surfaces, the runoff coefficient ranges from 0.6 to 0.9, depending on the material and slope.

Q2: How do I determine my water demand?
A: Calculate based on your intended usage - gardening, toilet flushing, laundry, etc. Average household usage can help estimate demand.

Q3: What rainfall data should I use?
A: Use average monthly or annual rainfall data for your location, preferably from reliable meteorological sources.

Q4: Can this calculator be used for large-scale systems?
A: While the basic principle applies, large-scale systems may require more complex calculations accounting for seasonal variations and multiple collection surfaces.

Q5: How accurate is this calculation?
A: It provides a good estimate for residential systems, but actual performance may vary based on rainfall patterns, system maintenance, and usage patterns.