Water to Air Heat Exchanger Calculator

Heat Transfer Formula:

\[ Q = \min (m_{water} \cdot c \cdot \Delta T_{water}, m_{air} \cdot c \cdot \Delta T_{air}) \]

Water Mass Flow Rate:

kg/s

Water Temperature Change:

Air Mass Flow Rate:

kg/s

Air Temperature Change:

Specific Heat Capacity:

J/kgK

Heat Transfer Rate (W):

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1. What is a Water to Air Heat Exchanger Calculator?

Definition: This calculator determines the heat transfer rate between water and air in a heat exchanger system.

Purpose: It helps engineers and HVAC professionals design and analyze heat exchanger systems for optimal performance.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ Q = \min (m_{water} \cdot c \cdot \Delta T_{water}, m_{air} \cdot c \cdot \Delta T_{air}) \]

Where:

\( Q \) — Heat transfer rate (Watts)
\( m_{water} \) — Water mass flow rate (kg/s)
\( \Delta T_{water} \) — Water temperature change (K)
\( m_{air} \) — Air mass flow rate (kg/s)
\( \Delta T_{air} \) — Air temperature change (K)
\( c \) — Specific heat capacity (J/kgK, default 4186 for water)

Explanation: The calculator determines the limiting heat transfer rate based on both the water and air sides of the exchanger.

3. Importance of Heat Exchanger Calculation

Details: Accurate heat transfer calculations ensure proper system sizing, energy efficiency, and thermal performance in HVAC and industrial applications.

4. Using the Calculator

Tips: Enter the mass flow rates and temperature changes for both water and air, along with the specific heat capacity (default 4186 J/kgK for water). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why do we take the minimum of the two calculations?
A: The heat exchanger is limited by whichever fluid (water or air) can absorb or release less heat, determining the system's maximum possible heat transfer.

Q2: What's a typical specific heat capacity for air?
A: Air has a specific heat of about 1005 J/kgK, but this calculator uses water's value (4186 J/kgK) as default for both fluids.

Q3: How do I find mass flow rates?
A: Mass flow rate = volumetric flow rate × density. For water at 20°C: 1 kg/s ≈ 0.001 m³/s. For air at 20°C: 1 kg/s ≈ 0.833 m³/s.

Q4: What temperature change should I use?
A: Use the temperature difference between inlet and outlet for each fluid in the heat exchanger.

Q5: Does this account for heat exchanger efficiency?
A: No, this calculates the theoretical maximum. For practical applications, multiply by the heat exchanger's effectiveness (typically 0.6-0.9).