1. What is a Heat Exchanger Size Calculator?

Definition: This calculator estimates the required heat transfer area (size) of a heat exchanger based on thermal performance parameters.

Purpose: It helps engineers and technicians determine the appropriate size of heat exchangers for various applications.

2. How Does the Calculator Work?

The calculator uses the fundamental heat exchanger equation:

Where:

• \( A \) — Heat exchanger area/size (m²)
• \( Q \) — Heat transfer rate (kW)
• \( U \) — Overall heat transfer coefficient (kW/m²·°C)
• \( \Delta T_m \) — Log mean temperature difference (°C)

Explanation: The heat transfer rate is divided by the product of the heat transfer coefficient and temperature difference to determine the required surface area.

3. Importance of Heat Exchanger Sizing

Details: Proper sizing ensures efficient heat transfer, optimal energy use, and cost-effective equipment selection for industrial processes.

4. Using the Calculator

Tips: Enter the heat transfer rate in kW, overall heat transfer coefficient (default 0.85 kW/m²·°C), and log mean temperature difference (default 20°C). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical U value for heat exchangers?
A: U values vary widely (0.1-2.5 kW/m²·°C) depending on fluids and exchanger type. Water-to-water is typically 0.8-1.5 kW/m²·°C.

Q2: How do I determine ΔT_m?
A: Calculate using hot and cold fluid inlet/outlet temperatures: ΔT_m = (ΔT₁ - ΔT₂) / ln(ΔT₁/ΔT₂).

Q3: Does this work for all exchanger types?
A: Yes, but U values differ significantly between shell-and-tube, plate, and other exchanger types.

Q4: Should I include a safety factor?
A: Yes, typically add 10-20% to the calculated area for fouling and design margins.

Q5: How do I find the heat transfer rate (Q)?
A: Q = m × c_p × ΔT, where m is mass flow rate and c_p is specific heat capacity.