Thermal Energy Released During Steam Condensation

Understanding the application of latent heat of vaporization in thermodynamic processes is crucial for a variety of industries, including power generation, chemical processing, and HVAC systems. This article aims to delve into the specific example of condensing steam at 100°C into water, providing a thorough explanation of the involved calculations and concepts.

Concept of Latent Heat and Condensation

Condensation is a phase transition where a substance changes from a gaseous state to a liquid state, releasing thermal energy in the process. In the context of steam, this process is significant as it involves converting high-temperature water vapor back into a liquid state.

Thermal Energy Calculation

The calculation of thermal energy released during condensation can be approached through the use of the latent heat of vaporization (Lv). The formula for determining the thermal energy (Q) released is given by:

Q m · Lv

Q: Thermal energy released in joules (J) m: Mass of the steam in kilograms (kg) Lv: Latent heat of vaporization in joules per kilogram (J/kg)

For this example, we are given:

Mass of the steam, m 1.2 kg Latent heat of vaporization, Lv 2.25 × 10^6 J/kg

Substituting these values into the formula:

Q 1.2 kg · 2.25 × 10^6 J/kg

Q 2.7 × 10^6 J

Thus, the thermal energy released when 1.2 kg of steam at 100°C is condensed to water at the same temperature is 2.7 million joules (2.7 MJ).

Alternative Approach Using Enthalpy of Water and Steam

Another method to calculate the energy released involves considering the enthalpy changes. Enthalpy is a measure of the total heat content of a system. The enthalpy of saturated steam at 100°C and 0.1014 MPa (1 atm) is given as 2675.61 kJ/kg, while the enthalpy of water at the same conditions is 419.1 kJ/kg. The energy released by condensing 1 kg of steam to water can be calculated as follows:

Energy released per kg of steam:

2675.61 kJ - 419.1 kJ 2256.51 kJ

For 1.2 kg of steam, the total energy released is:

2256.51 kJ/kg · 1.2 kg 2707.812 kJ

This alternative method also confirms that approximately 2707.812 kJ or 2.708 MJ of thermal energy is released during the process.

Conclusion

The condensation process of steam into water at 100°C is a fundamental thermodynamic process with significant practical applications. Understanding and calculating the thermal energy released during this phase change can help in optimizing energy systems and processes in various industrial settings. Whether employing the direct latent heat approach or the enthalpy method, both provide consistent and valuable insights into the energy dynamics involved.