AMME2262 Lecture Notes - Lecture 7: Thermal Efficiency, Waste Heat, Thermodynamic Temperature

• School: University of Sydney
• Department: Aeronautical Engineering (Mechanical)
• Course: AMME2262
• Professor: matthew dunn

Document Summary

Introduction to second law of thermodynamics (first law of thermodynamics: energy can neither be created nor destroyed) The first law provides no information on: the quality of energy, the direction of a process. Thermal energy reservoirs: bodies with relatively large thermal masses can be modelled as thermal energy reservoirs, temperature does not change no matter how much energy is being put into it. Steam power plant: a portion of the work output of a heat engine is consumed internally to maintain continuous operation. (cid:1857)(cid:1865)(cid:1864) (cid:1857)(cid:1858)(cid:1858)(cid:1857)(cid:1866)= (cid:1857)(cid:1872) (cid:1867)(cid:1863) (cid:1867)(cid:1873)(cid:1872)(cid:1868)(cid:1873)(cid:1872) (cid:1867)(cid:1872)(cid:1864) (cid:1857)(cid:1872) (cid:1866)(cid:1868)(cid:1873)(cid:1872) It is impossible for any device that operates on a cycle to receive heat from a single reservoir and produce a net amount of work: no heat engine can have a thermal efficiency of 100 percent. Heat transfer from a low to high temperature space requires a device called a refrigerator. Violation of the kelvin planck statement results in a violation of the calusius statement.