PHYS 123 Chapter Notes - Chapter 21: Brayton Cycle, Carnot Cycle, Heat Pump
Document Summary
Diagrams that show the energy inputs and energy outputs of a system are called energy input-output diagrams. A device can never convert all of its thermal energy to useful energy. A device that converts energy over to remain the same or to return to the same state over some repeating time interval is called a steady device. A cycle is when the device from its initial state undergoes some processes and comes back to its initial state. Steady devices e= 0, all energy inputs = all energy outputs, s= s dev+ senv. Because there is no entropy change for a quasistatic adiabatic process both ws do not contribute any entropy change to the environment. For a steady device to operate the energy input must equal the energy output and the entropy of the environment must increase. Entropy gradient ds/de is the measure of change in entropy caused by a given change in energy.
