Collection Efficiency When Collector Efficiency Factor Is Present Calculator

Formula Used:

\[ \eta_i = (F' \times (A_p/A_c) \times \tau\alpha_{av}) - (F' \times A_p \times U_l \times (T_f - T_a) \times 1/I_T) \]

Collector Efficiency Factor (F'):

Area of Absorber Plate (A_p):

m²

Gross Collector Area (A_c):

m²

Average Transmissivity-Absorptivity Product (τα_av):

Overall Loss Coefficient (U_l):

W/m²K

Average Fluid Temperature (T_f):

Ambient Air Temperature (T_a):

Flux Incident on Top Cover (I_T):

W/m²

Instantaneous Collection Efficiency (η_i):

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1. What Is The Collection Efficiency When Collector Efficiency Factor Is Present?

The instantaneous collection efficiency when collector efficiency factor is present represents the ratio of useful heat gain to radiation incident on the collector, accounting for the collector efficiency factor which relates actual thermal collector power to ideal collector power.

2. How Does The Calculator Work?

The calculator uses the formula:

\[ \eta_i = (F' \times (A_p/A_c) \times \tau\alpha_{av}) - (F' \times A_p \times U_l \times (T_f - T_a) \times 1/I_T) \]

Where:

\( F' \) — Collector efficiency factor
\( A_p \) — Area of absorber plate (m²)
\( A_c \) — Gross collector area (m²)
\( \tau\alpha_{av} \) — Average transmissivity-absorptivity product
\( U_l \) — Overall loss coefficient (W/m²K)
\( T_f \) — Average of inlet and outlet temperature of fluid (K)
\( T_a \) — Ambient air temperature (K)
\( I_T \) — Flux incident on top cover (W/m²)

Explanation: The formula calculates instantaneous collection efficiency by considering both the useful energy gain component and the heat loss component of the solar collector system.

3. Importance Of Collection Efficiency Calculation

Details: Accurate collection efficiency calculation is crucial for evaluating solar collector performance, optimizing system design, and predicting energy output for solar thermal applications.

4. Using The Calculator

Tips: Enter all required parameters with appropriate units. Ensure temperature values are in Kelvin, areas in square meters, and flux in watts per square meter. All values must be positive and valid.

5. Frequently Asked Questions (FAQ)

Q1: What is the collector efficiency factor?
A: The collector efficiency factor (F') represents the ratio of actual thermal collector power to the power of an ideal collector whose absorber temperature equals the fluid temperature.

Q2: What are typical values for transmissivity-absorptivity product?
A: Typical values range from 0.6 to 0.9 for high-quality solar collectors, depending on the glazing and absorber materials used.

Q3: How does ambient temperature affect collection efficiency?
A: Higher ambient temperatures reduce the temperature difference (T_f - T_a), which decreases heat losses and generally improves collection efficiency.

Q4: What is the significance of flux incident on top cover?
A: This represents the total solar radiation reaching the collector surface, which is the primary energy input that determines the maximum possible energy collection.

Q5: When is this efficiency calculation most accurate?
A: This calculation provides accurate results for steady-state conditions and is widely used for performance evaluation and comparison of different solar collector designs.