1. What is a Water Heat Exchanger Calculator?

Definition: This calculator estimates the heat transfer rate in a water heat exchanger based on the overall heat transfer coefficient, heat transfer area, and log mean temperature difference.

Purpose: It helps engineers and technicians determine the thermal performance of heat exchangers in HVAC, industrial processes, and power generation systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

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

Explanation: The heat transfer rate is calculated by multiplying the overall heat transfer coefficient by the heat transfer area and the temperature driving force (LMTD).

3. Importance of Heat Exchanger Calculations

Details: Proper heat exchanger sizing ensures efficient energy transfer, optimal system performance, and cost-effective operation.

4. Using the Calculator

Tips: Enter the U-value (typical range 300-2500 W/m² K for water-to-water exchangers), heat transfer area, and LMTD. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is LMTD and how is it calculated?
A: LMTD (Log Mean Temperature Difference) is the logarithmic average of the temperature differences between the hot and cold streams at each end of the exchanger.

Q2: What's a typical U-value for water heat exchangers?
A: For water-to-water heat exchangers, U typically ranges from 300-2500 W/m² K depending on design and flow conditions.

Q3: Can this calculator be used for other fluids?
A: Yes, but you must use appropriate U-values for the specific fluid combination.

Q4: How do I find the heat transfer area?
A: For shell-and-tube exchangers, calculate the total surface area of all tubes. For plate exchangers, sum the area of all plates.

Q5: Does this include fouling factors?
A: No, fouling factors should be accounted for in the U-value you input.