Effective Heat Transfer Coefficient For Variation Calculator

Effective Heat Transfer Coefficient Formula:

\[ h_e = h_{fp} \times \left(1 + \frac{2 \times L_f \times \Phi_f \times h_{ff}}{W \times h_{fp}}\right) + \frac{h_r \times h_{fb}}{h_r + h_{fb}} \]

Convective Heat Transfer Coeff of Solar (hfp):

W/m²K

Fin Height (Lf):

Fin Effectiveness (Φf):

Convective Heat Transfer Coeff of Solar Fin (hff):

W/m²K

Distance Between Fins (W):

Equivalent Radiative Heat Transfer Coefficient (hr):

W/m²K

Convective Heat Transfer Coeff of Solar Bottom (hfb):

W/m²K

Effective Heat Transfer Coefficient (he):

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1. What is the Effective Heat Transfer Coefficient Formula?

The effective heat transfer coefficient formula calculates the overall heat transfer coefficient between the absorber plate and the air stream, accounting for fin effects and radiative heat transfer. It provides a comprehensive assessment of heat transfer performance in solar thermal systems.

2. How Does the Calculator Work?

The calculator uses the effective heat transfer coefficient formula:

\[ h_e = h_{fp} \times \left(1 + \frac{2 \times L_f \times \Phi_f \times h_{ff}}{W \times h_{fp}}\right) + \frac{h_r \times h_{fb}}{h_r + h_{fb}} \]

Where:

\( h_{fp} \) — Convective heat transfer coefficient of solar (W/m²K)
\( L_f \) — Fin height (m)
\( \Phi_f \) — Fin effectiveness (-)
\( h_{ff} \) — Convective heat transfer coefficient of solar fin (W/m²K)
\( W \) — Distance between fins (m)
\( h_r \) — Equivalent radiative heat transfer coefficient (W/m²K)
\( h_{fb} \) — Convective heat transfer coefficient of solar bottom (W/m²K)

Explanation: The equation accounts for both convective heat transfer through fins and radiative heat transfer at the bottom surface, providing a comprehensive effective heat transfer coefficient.

3. Importance of Effective Heat Transfer Coefficient Calculation

Details: Accurate calculation of effective heat transfer coefficient is crucial for designing efficient solar thermal systems, optimizing heat exchanger performance, and predicting thermal behavior in various engineering applications.

4. Using the Calculator

Tips: Enter all required parameters with appropriate units. All values must be positive numbers. The calculator will compute the effective heat transfer coefficient based on the provided inputs.

5. Frequently Asked Questions (FAQ)

Q1: What is fin effectiveness?
A: Fin effectiveness is the ratio of the rate of heat transfer by use of fin to the rate of heat transfer without fin, indicating how effectively the fin enhances heat transfer.

Q2: Why is radiative heat transfer coefficient included?
A: Radiative heat transfer becomes significant at higher temperatures and must be considered for accurate thermal analysis in solar applications.

Q3: What are typical values for these parameters?
A: Typical values vary based on system design, but hfp and hff typically range 5-50 W/m²K, Lf 0.01-0.1 m, Φf 0.5-0.95, W 0.02-0.1 m, hr 5-20 W/m²K, hfb 5-30 W/m²K.

Q4: How does fin spacing affect the result?
A: Closer fin spacing (smaller W) generally increases the effective heat transfer coefficient by providing more surface area for heat transfer.

Q5: Can this formula be used for other applications?
A: While developed for solar thermal systems, this approach can be adapted for other finned heat exchanger applications with appropriate parameter adjustments.