Heat Exchanged NTU Method Calculator

Heat Exchanged Formula:

\[ Q = \epsilon \times C_{min} \times (T_1 - t_1) \]

Effectiveness of Heat Exchanger (ε):

(dimensionless)

Smaller Value (C_min):

W/K

Entry Temperature of Hot Fluid (T₁):

Entry Temperature of Cold Fluid (t₁):

Heat Exchanged (Q):

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1. What is the Heat Exchanged NTU Method?

The NTU (Number of Transfer Units) method is a technique used in heat exchanger analysis to determine the rate of heat transfer between two fluids at different temperatures. It provides an efficient way to calculate heat exchanged based on the effectiveness of the heat exchanger and the temperature difference.

2. How Does the Calculator Work?

The calculator uses the NTU method formula:

\[ Q = \epsilon \times C_{min} \times (T_1 - t_1) \]

Where:

\( Q \) — Heat exchanged (W)
\( \epsilon \) — Effectiveness of heat exchanger (dimensionless)
\( C_{min} \) — Smaller value of heat capacity rates (W/K)
\( T_1 \) — Entry temperature of hot fluid (K)
\( t_1 \) — Entry temperature of cold fluid (K)

Explanation: The formula calculates the actual heat transfer rate based on the heat exchanger's effectiveness and the maximum possible temperature difference.

3. Importance of Heat Exchanged Calculation

Details: Accurate heat exchange calculation is crucial for designing efficient heat exchangers, optimizing energy transfer in thermal systems, and ensuring proper sizing of heat exchange equipment in various industrial applications.

4. Using the Calculator

Tips: Enter effectiveness (0-1), C_min value (must be positive), and both entry temperatures in Kelvin. All values must be valid for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is the effectiveness of a heat exchanger?
A: Effectiveness is defined as the ratio of actual heat transfer to the maximum possible heat transfer, ranging from 0 to 1.

Q2: How is C_min determined?
A: C_min is the smaller of the two heat capacity rates (ṁ×c_p) for the hot and cold fluids flowing through the heat exchanger.

Q3: What are typical effectiveness values?
A: Effectiveness typically ranges from 0.6 to 0.9 for well-designed heat exchangers, depending on the type and configuration.

Q4: When is the NTU method preferred?
A: The NTU method is particularly useful when the outlet temperatures are unknown and the heat exchanger configuration is complex.

Q5: What are the limitations of this method?
A: The method assumes constant fluid properties, negligible heat loss to surroundings, and steady-state operation of the heat exchanger.