Self Check: Energy Conversion Devices

For each of the following examples, determine the types of useful energy and undesired energy for the given energy converter.

 

Example 1: Lawnmower with a chemical energy input. (Hint: How do you know when your neighbor is mowing the lawn?)

Example 2: Car with a chemical energy input. (Hint: Think about mufflers, tires and generator.)

Example 3: Television with an electrical energy input. (Hint: Have you ever felt the back of your TV after it has been on for a few hours?)

Example 4: Desktop computer with an electrical energy input. (Hint: What’s in your tower and why?)

 

Answers:

Example 1: The useful energy for a lawnmower is mechanical while the undesired energy is thermal (heat) and radiation (noise).

Example 2: The useful energy for a car is mechanical while the undesired energy is thermal or heat (tail pipe).

Example 3: The useful energy for a TV is radiation (light and sound) and the undesirable energy is heat (from circuits).

Example 4: The useful energy for a computer is radiation (light and sound) and the undesirable energy is heat (circuits – electrons moving through system) and mechanical (fan for cooling).