Chapter 12.2, Problem 29SSC

To determine

The energy transformations and transfers in a heat engine and the reason for the increased entropy.

Explanation of Solution

Introduction:

A heat engine is a machine used to convert heat from a source to mechanical work. It is limited by the law of conservation of energy which says that energy can neither be formed nor destroyed; it can only be changed from one form to another. Entropy is the measure of disorder in a system.

A heat engine converts the chemical potential energy stored in fuel to the thermal energy in the gases which in turn is converted into kinetic energy in moving the piston or turbines. Some amount of energy is also wasted which is released into the environment called thermal exhaust. Entropy is the measure of disorder in the system. It either increases or remains constant in any process. The chemical energy stored in fuel has lower entropy than the kinetic energy stored in gases after combustion. The thermal exhaust also increases the entropy of the environment.