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Solar Water Heater Size Calculator

Solar Heater Size Formula:

\[ \text{Size} = \frac{\text{Daily Hot Water Use}}{\text{Insolation} \times \text{Efficiency}} \]

liters
kWh/m²
(0-1)

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1. What is a Solar Water Heater Size Calculator?

Definition: This calculator estimates the required size (area) of a solar water heating system based on daily hot water needs, solar insolation, and system efficiency.

Purpose: It helps homeowners and installers determine the appropriate solar collector area needed to meet hot water demands.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ \text{Size} = \frac{\text{Daily Hot Water Use}}{\text{Insolation} \times \text{Efficiency}} \]

Where:

Explanation: The daily hot water requirement is divided by the product of insolation and efficiency to determine the necessary collector area.

3. Importance of Proper Sizing

Details: Correct sizing ensures adequate hot water supply while avoiding excessive costs from oversized systems or insufficient hot water from undersized systems.

4. Using the Calculator

Tips: Enter your daily hot water use in liters, local solar insolation (default 4.5 kWh/m²), and system efficiency (default 0.5). Efficiency must be between 0 and 1.

5. Frequently Asked Questions (FAQ)

Q1: How do I determine my daily hot water use?
A: Estimate based on household size (50-80L per person) or measure actual usage from your water heater.

Q2: Where can I find local insolation values?
A: Check solar maps from government agencies or use 4.5 kWh/m² as a general average.

Q3: What affects system efficiency?
A: Collector type (flat plate vs evacuated tube), installation angle, shading, and heat loss factors.

Q4: Should I round up the calculated size?
A: Yes, it's recommended to round up to the nearest standard collector size available.

Q5: Does this account for seasonal variations?
A: No, size for your highest demand or lowest insolation period if you need year-round performance.

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