The first step allowed you to acquire the basic concepts of Engineering thermodynamics and to learn using Thermoptim to model the basic cycles.

During this second step, you will start consolidating your knowledge by studying some additional theoretical bases (including exergy and heat exchangers), and analyzing variants of the basic cycles. In a second step you will address combined cycles and cogeneration (combined heat and power CHP).

Cycles studied becoming more complex, the models you will study require more work than the previous ones. Supplements concerning Thermoptim modeling will be presented, in particular when analyzing models of reciprocating internal combustion engines (diesel and gasoline).

The theory of exergy provides a quite rigorous thermodynamic framework to quantify the quality of any system, open or closed, in steady-state or not. Exergy balances are increasingly accepted as a preferred tool to compare and optimize thermodynamic cycles.

During this step, you will have the opportunity to become familiar with this concept and learn how to implement it for different cycle analyses.

Methodological explanations on the establishment of exergy balances are provided in Section Exergy analysis and in session S06En Exergy balances .

Heat exchangers are devices which transfer heat between two fluids at different temperatures. As such, they play a fundamental role in many energy technologies.

Although their mode of operation is usually simple, since they are fixed components without moving parts, experience shows that many difficulties arise when it comes to set them wisely.

During this step, you will learn about heat exchangers and learn how to model them. They are presented in specific thematic pages and in session S18En Thermodynamics of heat exchangers .

Thermoptim is a software package that allows much easier (and secure) modeling of energy systems. The fact remains that its use requires a number of precautions when you are interested in complex technologies, particularly if they involve different fluids, with mixtures and combustion, and if heat exchangers exist.

To make the best use of the potential of simulators as Thermoptim by performing reliable modeling of complex systems, you must adopt good methods of construction and verification of models, such as those presented in the section Modeling simple and complex systems . We suggest you to refer to a note specifically dealing with these issues .

Now that you have mastered the basic cycles, you will study their variants and more complex cycles. You will also learn how to build up exergy balances in order to quantitatively analyze the irreversibilities that take place in these cycles.

Although you have already calculated energy balances during the first step, it is time to further discuss issues related to cycle analyses, which is done in session S09En General issues on cycles .

Regenerative gas turbine

If necessary, go back to the thematic pages dedicated to gas turbines.

The gas turbine cycle studied in session S22En can be improved thanks to a regenerator, heat exchanger which allows one to preheat the compressed air before entering the combustion chamber.

Session S23En Gas turbine exercise (exergy balances, regeneration) explains how this can be done.

As practical exercise, you can make sensitivity studies of the influence of the regenerator effectiveness or the compression ratio on the performance of the machine.

Extraction and reheat steam power plants

If necessary, go back to the thematic pages dedicated to steam power plants.

Similarly, the simple steam poer plant cycle can be improved, as explained in sessions S27En 300 MW extraction and reheat steam cycle and S28En 300 MW steam cycle exergy balances .

As practical exercise, you can make sensitivity studies of the influence of the extraction rate on the performance of the machine.

Water chiller exergy balance, heat pumps

If necessary, go back to the thematic pages dedicated to vapor compression refrigeration machines.

Session S32En Water chiller exergy balance will allow you to analyze the exergy balance of the refrigeration machine studied during the first step. You will see that, athough its Coefficient Of Performance COP is high, its exergy efficiency is low.

As practical exercise, you can make sensitivity studies of the influence of the ambient temperature on the performance of the machine.

Session S33En Heat pump evaporator design exercise will allow you to compare thermodynamic heating to conventional or electric heating, and to size a heat exchanger.

Diesel and gasoline engines

If necessary, go back to the thematic pages dedicated to reciprocating internal combustion engines.

Sessions S38En Diesel engine exercise and S39En Gasoline engine exercise will show you how to model reciprocating engines whose combustion may be considered as taking place in three different phases, all in closed system: constant volume, constant pressure and constant temperature.

Combined cycles

You should start by studying the combined cycle thematic pages which will present you basic technological aspects.

Session S41En Single pressure combined cycle exercise will then show you how to determine the steam cycle flow-rate allowing one to maximize the capacity and efficiency of a single pressure combined cycle.

Cogeneration plants

You should start by studying the the CHP thematic pages which will present you basic technological aspects.

Session S46En Micro-gas turbine cogeneration exercise will then show you how to model a CHP plant based on the gas turbine studied before.