23-2 인천댿� 기계공학실험 냉동사이클 레포트

1. Introduction and Theory
(1) Thermodynamics Laws
(1-1)Zeroth Law of Thermodynamics (Thermal Equilibrium)
If two systems are each in thermal equilibrium with a third system, then they are in thermal equilibrium with each other. This law defines the concept of temperature.
(1-2)First Law of Thermodynamics (Law of Energy Conservation)
Energy cannot be created or destroyed; it can only be transformed from one form to another. The total energy of a system remains constant, though its form may change.
(1-3) Second Law of Thermodynamics (Entropy Increase Law)
Entropy, or the degree of disorder, always increases or at least remains constant in an isolated system. This implies that heat naturally flows from a higher temperature to a lower temperature.
(1-4) Third Law of Thermodynamics
As the temperature approaches absolute zero (0K, -273.15°C), the entropy of a pure crystal approaches zero. At absolute zero, all molecular motion stops, and the system is expected to be in a state of perfect order, but in reality, reaching this state is impossible.