Closed System

Definition

A closed system is a physical system that does not exchange matter with its surroundings but can exchange energy in the form of heat or work. This concept allows for the analysis of energy transfers while keeping the mass constant, making it essential for understanding various thermodynamic processes and principles.

5 Must Know Facts For Your Next Test

1. In a closed system, the total mass remains constant as no mass enters or leaves the system boundaries.
2. Energy can be transferred into or out of a closed system, influencing its internal energy, temperature, and pressure.
3. The First Law of Thermodynamics applies to closed systems, indicating that the change in internal energy equals the heat added minus the work done by the system.
4. Closed systems are commonly used in thermodynamic models to simplify calculations related to energy transformations and efficiencies.
5. Processes such as heating and cooling can occur in closed systems without altering their mass, making them vital for analyzing thermal behaviors.

Review Questions

• How does the concept of a closed system facilitate understanding energy exchanges in thermodynamics?
  • The concept of a closed system simplifies the analysis of energy exchanges by allowing focus on how energy is transferred without changes in mass. By defining clear boundaries where only energy can enter or exit, we can apply principles such as the First Law of Thermodynamics more effectively. This makes it easier to calculate changes in internal energy, temperature, and pressure during various processes.
• Discuss the significance of applying exergy balance principles in a closed system and how it differs from open systems.
  • Applying exergy balance principles in a closed system allows for precise evaluation of available work potential from energy transfers while ignoring mass flow. In contrast to open systems, where mass and energy exchanges complicate calculations, closed systems enable clearer assessments of efficiency and irreversibilities. This focus on energy transformation provides insight into optimizing processes and minimizing losses within the defined boundaries.
• Evaluate how understanding closed systems contributes to minimizing exergy destruction in practical applications.
  • Understanding closed systems is crucial for minimizing exergy destruction since it helps identify how energy is utilized and lost during processes. By analyzing how energy enters and exits these systems, we can pinpoint inefficiencies and optimize designs for thermal devices, engines, or reactors. This approach promotes better resource management and sustainability by maximizing useful work output while minimizing waste and irreversibilities.

Related terms

Isolated System: An isolated system is a type of closed system that does not exchange either matter or energy with its surroundings, making it completely self-contained.

Heat Transfer: Heat transfer refers to the movement of thermal energy between a closed system and its surroundings, typically through conduction, convection, or radiation.

Work: Work is the energy transfer that occurs when a force acts over a distance, which can happen in a closed system when energy is transferred through mechanical means.