Specific Heat Of Air During Humidification Calculator

Specific Heat of Air Formula:

\[ c_p = \frac{(Y_w - Y_{\infty}) \times h_{fg}}{(T - T_{\infty}) \times Le^{0.67}} \]

Absolute Humidity of Air(tw):

kg/kg

Absolute Humidity of Air(atm):

kg/kg

Enthalpy of Evaporation:

J/kg·K

Temperature:

Air Temperature:

Lewis Number:

Specific Heat of Air (cₚ):

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1. What is Specific Heat of Air During Humidification?

The specific heat of air during humidification represents the amount of heat energy required to raise the temperature of a unit mass of air by one degree while accounting for the moisture content changes during the humidification process.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ c_p = \frac{(Y_w - Y_{\infty}) \times h_{fg}}{(T - T_{\infty}) \times Le^{0.67}} \]

Where:

\( Y_w \) — Absolute humidity at wet bulb temperature (kg/kg)
\( Y_{\infty} \) — Absolute humidity at atmospheric temperature (kg/kg)
\( h_{fg} \) — Enthalpy of evaporation (J/kg·K)
\( T \) — Temperature (K)
\( T_{\infty} \) — Air temperature (K)
\( Le \) — Lewis Number (dimensionless)

Explanation: This formula calculates the specific heat of air by considering the humidity difference, evaporation enthalpy, temperature gradient, and the Lewis number which relates thermal and mass diffusivity.

3. Importance of Specific Heat Calculation

Details: Accurate calculation of specific heat during humidification is crucial for HVAC system design, psychrometric calculations, energy efficiency analysis, and thermal comfort studies in various engineering applications.

4. Using the Calculator

Tips: Enter all values in appropriate units. Ensure temperature values are in Kelvin, humidity values in kg/kg, and enthalpy in J/kg·K. All values must be positive and non-zero.

5. Frequently Asked Questions (FAQ)

Q1: What is the Lewis Number and why is it important?
A: The Lewis Number is a dimensionless number that represents the ratio of thermal diffusivity to mass diffusivity. It's crucial for characterizing simultaneous heat and mass transfer processes.

Q2: How does humidification affect specific heat of air?
A: Humidification increases the moisture content of air, which affects its thermal properties since water vapor has different specific heat characteristics than dry air.

Q3: What are typical values for specific heat of humid air?
A: For dry air, specific heat is approximately 1005 J/kg·K. For humid air, it typically ranges between 1000-2000 J/kg·K depending on moisture content.

Q4: Why use Kelvin instead of Celsius for temperature?
A: Kelvin is used because it's an absolute temperature scale required for thermodynamic calculations involving temperature differences and ratios.

Q5: What applications use this specific heat calculation?
A: This calculation is used in HVAC design, drying processes, meteorological studies, industrial humidification systems, and environmental control systems.