1. What is a Heat Exchanger Calculator?

Definition: This calculator determines the heat transfer rate in a heat exchanger using the fundamental equation Q = U × A × LMTD.

Purpose: It helps engineers and technicians estimate the thermal performance of heat exchangers in various applications.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Heat transfer rate (Watts)
• \( U \) — Overall heat transfer coefficient (W/m²K)
• \( A \) — Heat transfer area (m²)
• \( LMTD \) — Log mean temperature difference (K)

Explanation: The product of these three parameters gives the rate of heat transfer between the hot and cold fluids.

3. Importance of Heat Exchanger Calculations

Details: Accurate calculations ensure proper heat exchanger sizing, energy efficiency, and system performance in HVAC, refrigeration, and industrial processes.

4. Using the Calculator

Tips: Enter the U-value (typically 10-1000 W/m²K depending on type), heat transfer area, and LMTD. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical U-value range?
A: U-values vary widely: 10-40 for air-to-air, 100-250 for water-to-water, and up to 1000 for phase-change heat exchangers.

Q2: How is LMTD calculated?
A: LMTD = (ΔT1 - ΔT2)/ln(ΔT1/ΔT2), where ΔT1 and ΔT2 are temperature differences at each end.

Q3: What if my heat exchanger isn't counterflow?
A: Multiply LMTD by a correction factor (typically 0.7-1.0) for crossflow or parallel flow configurations.

Q4: Does this work for all heat exchanger types?
A: Yes, but U-values vary significantly between shell-and-tube, plate, and other heat exchanger types.

Q5: How accurate is this calculation?
A: It provides a theoretical maximum - actual performance may be 5-15% lower due to fouling and other factors.