Heat Exchanger Size Calculator

Heat Exchanger Area Formula:

\[ A = \frac{Q}{U \times \Delta T_{lm}} \]

Heat Transfer Rate (Q):

Overall Heat Transfer Coefficient (U):

W/m²K

Log Mean Temperature Difference (ΔT_lm):

Heat Exchanger Area (A):

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1. What is Heat Exchanger Area Calculation?

The heat exchanger area calculation determines the required surface area for efficient heat transfer between two fluids. It is a critical parameter in heat exchanger design and selection for various industrial applications.

2. How Does the Calculator Work?

The calculator uses the fundamental heat exchanger equation:

\[ A = \frac{Q}{U \times \Delta T_{lm}} \]

Where:

\( A \) — Heat exchanger area (m²)
\( Q \) — Heat transfer rate (W)
\( U \) — Overall heat transfer coefficient (W/m²K)
\( \Delta T_{lm} \) — Log mean temperature difference (K)

Explanation: This equation relates the required heat transfer area to the thermal load, overall heat transfer coefficient, and the driving temperature difference.

3. Importance of Heat Exchanger Sizing

Details: Proper heat exchanger sizing is crucial for efficient heat transfer, energy conservation, cost optimization, and ensuring the system meets process requirements without being oversized or undersized.

4. Using the Calculator

Tips: Enter heat transfer rate in watts, overall heat transfer coefficient in W/m²K, and log mean temperature difference in Kelvin. All values must be positive and non-zero.

5. Frequently Asked Questions (FAQ)

Q1: What is log mean temperature difference (LMTD)?
A: LMTD is the logarithmic average of the temperature difference between the hot and cold fluids at each end of the heat exchanger, representing the effective driving force for heat transfer.

Q2: How do I determine the overall heat transfer coefficient?
A: The U-value depends on the heat exchanger type, materials, fluid properties, and flow arrangements. It can be calculated from individual heat transfer coefficients and fouling factors.

Q3: What are typical U-values for different heat exchangers?
A: U-values range from 25-250 W/m²K for gas-gas, 250-1000 W/m²K for liquid-gas, and 800-2500 W/m²K for liquid-liquid heat exchangers, depending on the specific application.

Q4: When is this calculation method applicable?
A: This method is suitable for preliminary sizing of various heat exchanger types including shell-and-tube, plate, and double-pipe heat exchangers with counter-current or co-current flow.

Q5: What factors affect heat exchanger performance?
A: Key factors include fouling, flow rates, fluid properties, temperature approach, pressure drop limitations, and heat exchanger geometry.