Cycles  A series of processes which return a system to its initial state  Heat engine: receives heat; does work  Reversed cycle: cool or heat when work done on system

Limitations  > 100% thermal efficiency  Heat → cold?

Performance  Thermal efficiency  Coefficient of performance Cooling Heating

Carnot cycle  Ideal cycle  Four reversible processes 1 → 2 reversible, adiabatic compression 2→ 3 reversible, isothermal expansion 3→ 4 reversible, adiabatic expansion 4 → 1 reversible, isothermal compression

Carnot cycle  Thermal efficiency  Cooling & heating

Industrial cycles  Models compared to real cycles  Models compared to Carnot cycles  Heat engines Otto: SIIC Diesel: CIIC Brayton: gas turbine, jet engine Rankine: steam turbine  Reversed cycle Air conditioning-refrigeration Heat pump

Rankine Cycle

 Generate electricity  Drive major equipment  Vapor power cycle

Rankine cycle  Fossil fuel  Wood  Garbage  Nuclear reaction

Rankine Cycle  Water Cheap Available Stable Nontoxic High heat capacity High heat transfer rate

Chapter 8: Vapor Power Systems / F8-1 To save, right click on the image and choose "Save As" from the pop-up menu.

Rankine cycle  Water pump  Steam generator  Turbine  Condenser

Rankine cycle  Performance Thermal efficiency bwr Steam rate Heat rate