Wet Bulb Temperature Of Humidification Calculator

Wet Bulb Temperature Formula:

\[ T_w = T_{\infty} - \left( \frac{0.622 \cdot h_{fg}}{c_p \cdot Le^{0.67}} \right) \cdot \left( \frac{P_w}{P_T} - \frac{P_{\infty}}{P_T} \right) \]

Air Temperature:

°C

Enthalpy of Evaporation:

J/kg·K

Specific Heat of Air:

J/kg·K

Lewis Number:

Partial Pressure:

Total Pressure:

Partial Pressure in Air:

Wet Bulb Temperature:

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1. What is Wet Bulb Temperature?

Wet Bulb Temperature is the lowest temperature that can be reached by the evaporation of water only. It represents the temperature read by a thermometer covered in water-soaked cloth over which air is passed.

2. How Does the Calculator Work?

The calculator uses the Wet Bulb Temperature formula:

\[ T_w = T_{\infty} - \left( \frac{0.622 \cdot h_{fg}}{c_p \cdot Le^{0.67}} \right) \cdot \left( \frac{P_w}{P_T} - \frac{P_{\infty}}{P_T} \right) \]

Where:

\( T_w \) — Wet Bulb Temperature (°C)
\( T_{\infty} \) — Air Temperature (°C)
\( h_{fg} \) — Enthalpy of Evaporation (J/kg·K)
\( c_p \) — Specific Heat of Air (J/kg·K)
\( Le \) — Lewis Number (dimensionless)
\( P_w \) — Partial Pressure at wet bulb temperature (Pa)
\( P_T \) — Total Pressure (Pa)
\( P_{\infty} \) — Partial Pressure in air (Pa)

Explanation: This formula calculates the wet bulb temperature based on thermodynamic properties and pressure differences in humid air.

3. Importance of Wet Bulb Temperature

Details: Wet bulb temperature is crucial for understanding human thermal comfort, designing HVAC systems, predicting weather patterns, and assessing industrial processes involving humidification and dehumidification.

4. Using the Calculator

Tips: Enter all required parameters with appropriate units. Ensure values are positive and within reasonable physical ranges for accurate results.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between dry bulb and wet bulb temperature?
A: Dry bulb temperature measures actual air temperature, while wet bulb temperature measures the cooling effect of evaporation and is always equal to or lower than dry bulb temperature.

Q2: Why is Lewis number important in this calculation?
A: The Lewis number represents the ratio of thermal diffusivity to mass diffusivity and accounts for simultaneous heat and mass transfer in the evaporation process.

Q3: What are typical values for enthalpy of evaporation?
A: For water at standard conditions, the enthalpy of evaporation is approximately 2257 kJ/kg or 2.257 × 10⁶ J/kg.

Q4: How does wet bulb temperature relate to humidity?
A: The difference between dry bulb and wet bulb temperatures indicates the humidity level - smaller differences indicate higher humidity, while larger differences indicate drier air.

Q5: What are the limitations of this calculation?
A: This calculation assumes ideal conditions and may not account for all real-world factors such as air velocity, radiation effects, or non-ideal gas behavior in extreme conditions.