1. What is Specific Internal Energy of Water?

The specific internal energy of water is the energy per unit mass associated with the molecular motion and interactions of water molecules. It's an important thermodynamic property used in heat transfer and energy balance calculations.

2. How Does the Calculator Work?

The calculator uses the simplified formula:

Where:

• \( u \) — Specific internal energy (J/kg)
• \( c \) — Specific heat capacity of water (J/kg°C)
• \( T \) — Temperature (°C)

Explanation: This linear approximation is valid for liquid water under normal conditions where the specific heat capacity is relatively constant.

3. Importance of Specific Internal Energy Calculation

Details: Calculating specific internal energy is essential for thermodynamic analysis, heat transfer calculations, and energy system design in engineering applications.

4. Using the Calculator

Tips: Enter the specific heat capacity (default is 4186 J/kg°C for water) and temperature in °C. The calculator will compute the specific internal energy.

5. Frequently Asked Questions (FAQ)

Q1: Is specific heat constant for all temperatures?
A: No, it varies slightly with temperature, but 4186 J/kg°C is a good approximation for liquid water between 0-100°C.

Q2: How does this differ from enthalpy?
A: Enthalpy includes flow work (pV term), while internal energy does not. For liquids, the difference is often small.

Q3: What's the reference state for zero energy?
A: This calculation gives energy relative to 0°C, where u=0 is assumed.

Q4: Can this be used for phase changes?
A: No, this simple formula doesn't account for latent heat during phase transitions.

Q5: What about high-pressure water?
A: At high pressures, more complex equations of state are needed for accurate calculations.