1. What is Heat Exchanger Capacity?

Definition: Heat exchanger capacity (Q) represents the actual heat transfer rate between two fluids in a heat exchanger.

Purpose: This calculation helps engineers determine the performance and sizing requirements for heat exchangers in various applications.

2. How Does the Calculator Work?

The calculator uses the effectiveness-NTU method formula:

Where:

• \( Q \) — Heat exchanger capacity (Watts)
• \( \epsilon \) — Effectiveness (dimensionless, 0-1)
• \( C_{min} \) — Minimum capacity rate (W/K)
• \( T_{h,in} \) — Hot fluid inlet temperature (K)
• \( T_{c,in} \) — Cold fluid inlet temperature (K)

Explanation: The effectiveness represents how close the heat exchanger approaches the maximum possible heat transfer, while \( C_{min} \) is the smaller of the two fluid capacity rates.

3. Importance of Heat Exchanger Capacity

Details: Accurate capacity calculation ensures proper heat exchanger selection, energy efficiency, and system performance in HVAC, power plants, and industrial processes.

4. Using the Calculator

Tips:

• Effectiveness (ε) typically ranges from 0.6 to 0.9 for most heat exchangers
• \( C_{min} \) is the product of mass flow rate and specific heat of the fluid with smaller capacity rate
• Temperatures must be in absolute units (Kelvin)

5. Frequently Asked Questions (FAQ)

Q1: What is effectiveness in heat exchangers?
A: Effectiveness is the ratio of actual heat transfer to the maximum possible heat transfer.

Q2: How do I determine C_min?
A: Calculate \( C = \dot{m} \times c_p \) for both fluids and use the smaller value.

Q3: Can I use Celsius instead of Kelvin?
A: Yes, for temperature differences (ΔT), since the degree size is the same in both scales.

Q4: What affects heat exchanger effectiveness?
A: Flow arrangement, heat exchanger type, surface area, and fluid properties.

Q5: How does capacity relate to heat exchanger size?
A: Higher capacity requirements generally need larger heat exchangers with more surface area.