Question

What are power cycles?

Answer 1

Power cycles:

Where $W$ is the work done.
$P$ is the pressure.
$V$ is the volume.
$∆V$ is the change in the volume.

1. Power cycles are used to transform some heat input into mechanical work output, whereas heat pump cycles use mechanical work as the input to transfer heat from low to high temperatures.
2. By managing the process direction, cycles made completely of quasi-static processes can function as power or heat pump cycles.
3. The clockwise and counterclockwise directions on a pressure-volume (PV) diagram or temperature-entropy diagram represent power and heat pump cycles, respectively.
4. An example of a power cycle is the Otto cycle.

Otto cycle:

1. An Otto cycle is an idealized thermodynamic cycle that describes the functioning of a typical spark ignition piston engine.
2. It is the thermodynamic cycle most commonly found in automobile engines.
3. Heat is transferred during the constant volume process $2-3.$
4. During the isentropic expansion process $3-4,$ this heat is converted into useful work by means of a piston.
5. As we know, pressure is directly proportional to temperature, Due to heat addition, temperature increases hence pressure also.
6. This increased pressure makes the piston move and hence gives useful work.

Thus, power cycles are those which are used to transform some heat input into mechanical work output.