Heat Engines and Cycles

Lab Day 6: Heat Engines and Cycles Experiments
Purpose:

The purpose of this lab was to analyze the different types of heat engines including the carnot engine cycle and determine how to maximize the efficiency of the engine based on how the engines work. We will use the pV diagram in order to consider its four main elements in a high efficiency heat engine cycle.

Experiment:

The first demonstration showed a hypno-disc that is attached to a conductor with two sides where one side is placed with a conductor in cold water consisting of ice and water while the other side is placed in heat. The result showed the disc spinning counter -clockwise. When switched, the results showed the disc spinning in the opposite direction. The question that is proposed is: which part would be cooled and which part will be heated?  As a result, the right side was heated and the left side was cooled, which is the thermoelectric effect in which the voltage itself allows one side to be extremely hotter than the other (confirmed through touching the two sides) without the help of the torch.


The predictions were correct and one side was hotter than the
other when the voltage itself was at work using the conductors

 

The red conductor is the cold while the black
conductor is the hot.
One side is definitely hotter than the other.

In this part, we have a heat engine connected to electricity due to a voltage and this is an example where work is done to produce a temperature difference. As the electricity is run through the conductor, there is work done on the the transfer of heat. As a result, one side is cold and one side is left hot. This is interesting because in reverse, we also have heat engines that produces work due to a temperature difference. A refrigerator is a type of heat engine that is ran in a similar fashion to this experiment where the inside is left cold and the outside is warm where we can use work(done by electricity) to create a temperature difference.

The Cv and Cp was derived where we were able to find the ratio of Cp/Cv.



Further calculations and substitutions

Calculations part 2

We then calculated the symbolic derivations of  work done in an adiabatic process. Below shows calculations to identify the work in functions of pressure and volume using gamma.

Calculations part 1

Calculations part 3

Calculations part 4

 

 

We can calculate the thermal efficiency by identifying this as an ideal gas. The internal energy depends on the

The 4 point cycle: Heat engines represent a parallelogram where it returns to its original

 

Next, we looked at a cylinder where there are different points where the cylinder first goes from a minimum to maximum volume where air is absorbed in which we have constant pressure in the intake of air stage. This is representative of a isobaric process. When we reach a high pressure at its maximum, which is sparked by the ignition of air and gas there is evidence of isochoric process where the volume remains constant. At the last point of the cycle, the air is released and therefore we have a cycle that repeats itself after. The idea of air being compressed in this engine show that it is going through an adiabatic process where the heat is constant.

Heat Engines and

How to increase power