1. What is Humidity Ratio To Relative Calculator?

The Humidity Ratio To Relative calculator converts humidity ratio (w) to relative humidity (RH) using temperature (T) and pressure (P). It's essential for psychrometric calculations in HVAC, meteorology, and industrial processes.

2. How Does the Calculator Work?

The calculator uses the following formula:

Where:

• \( w \) — Humidity ratio (kg water/kg dry air)
• \( P \) — Total pressure (kPa)
• \( P_{ws}(T) \) — Saturation vapor pressure at temperature T (kPa)
• \( T \) — Temperature (°C)
• 0.62198 — Ratio of molecular weights of water and dry air

Explanation: The equation relates the actual water vapor content (humidity ratio) to the maximum possible water vapor content at a given temperature (saturation vapor pressure).

3. Importance of RH Calculation

Details: Relative humidity is crucial for comfort assessment, process control, and equipment design in various industries. It affects human comfort, material properties, and chemical reactions.

4. Using the Calculator

Tips: Enter humidity ratio in kg/kg, temperature in °C, and pressure in kPa. Standard atmospheric pressure is 101.325 kPa. All values must be valid (w > 0).

5. Frequently Asked Questions (FAQ)

Q1: What is humidity ratio?
A: Humidity ratio (or mixing ratio) is the mass of water vapor per unit mass of dry air (kg/kg).

Q2: What's the difference between humidity ratio and relative humidity?
A: Humidity ratio measures absolute moisture content, while RH measures moisture relative to maximum possible at current temperature.

Q3: What is saturation vapor pressure?
A: The maximum partial pressure of water vapor at a given temperature when air is saturated.

Q4: How accurate is this calculation?
A: The Magnus formula for Pws is accurate to within ±0.1% for -20°C to 50°C. Overall accuracy depends on input precision.

Q5: When is this conversion most useful?
A: When working with psychrometric charts or processes where humidity ratio is measured but RH is needed for control or analysis.