Partial Pressure Of Water Vapour When Temperature Effects Are Considered Calculator

Formula Used:

\[ e = e_w - 0.7 \times \Delta T \]

Partial Pressure of Water Vapour (e):

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1. What is Partial Pressure of Water Vapour?

Partial pressure of water vapour is the vapour pressure in any gas mixture in equilibrium with solid or liquid water. It represents the contribution of water vapor to the total pressure of the gas mixture.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ e = e_w - 0.7 \times \Delta T \]

Where:

\( e \) — Partial pressure of water vapour (Millibar)
\( e_w \) — Saturated vapor pressure of water (Millibar)
\( \Delta T \) — Temperature change (°C)

Explanation: This formula accounts for the effect of temperature changes on the partial pressure of water vapor, with a coefficient of 0.7 representing the rate of change per degree Celsius.

3. Importance of Partial Pressure Calculation

Details: Calculating partial pressure of water vapor is crucial in meteorology, HVAC systems, industrial processes, and environmental studies where humidity and temperature effects need to be accurately determined.

4. Using the Calculator

Tips: Enter saturated vapor pressure of water in Millibar and temperature change in °C. Ensure values are valid (e_w ≥ 0).

5. Frequently Asked Questions (FAQ)

Q1: Why is the coefficient 0.7 used in the formula?
A: The coefficient 0.7 represents the empirical relationship between temperature change and vapor pressure reduction, derived from experimental data.

Q2: What are typical values for saturated vapor pressure?
A: Saturated vapor pressure varies with temperature. At 0°C it's about 6.11 mbar, at 20°C about 23.4 mbar, and at 100°C it's 1013 mbar.

Q3: When is this calculation most useful?
A: This calculation is particularly useful in atmospheric sciences, HVAC design, and industrial processes where temperature changes affect humidity levels.

Q4: Are there limitations to this formula?
A: This is an empirical formula and may have limited accuracy under extreme conditions or for very large temperature changes.

Q5: How does temperature affect water vapor pressure?
A: As temperature increases, the saturated vapor pressure increases exponentially. Temperature changes directly affect the equilibrium between water vapor and liquid water.