Module for self-training to energy powered systems

Module for self-training to energy powered systems

This pedagogic set dedicated to self-training deals with the energy powered systems based on heat conversion. It stresses with particular emphasis the main types of compressible fluid machines (compressors, internal combustion engines, gas turbines, steam gas turbines, refrigeration machines or facilities, combined cycles, cogeneration).

It will help you:

• understand the design principles of these systems;
• have a global view of the various technologies used for their construction;
• and finally become acquainted with the classical and up-to-date analysis methods (diagrams, charts, software applications, etc.).

This pedagogic set is mainly based on the use of a simulation software package, Thermoptim, and on the Diapason e-learning modules.

The Diapason modules are educational animated slide shows, each provided with a soundtrack. This is Information and Communication Technology (ICT) applied to education. These modules allow students to work by themselves at their own pace, alone or in groups, and access online at any time:

• the oral explanations given by the teacher in addition to written materials available to them;
• practical exercises using the simulator, which gives them the opportunity to familiarize themselves with the various cycles and their analysis methods.

In this module, we consider that you are already familiar with basic thermodynamics concepts, and in particular with the notion of entropy. If this is not the case, we suggest that you start by studying a note entitled First steps in thermodynamics (absolute beginners) .

In this document we use a lightweight educational presentation as we seek to minimize the background in mathematics and physics necessary for understanding the basic energy conversion cycles, our goal being to make them accessible to readers unfamiliar with the language of specialists in thermodynamics. We show in particular that essential concepts can be presented without resorting to the entropy function, which is introduced only in the second part of the presentation.

This pedagogic set is divided into three main steps:

1) The acquisition of concepts and tools . This first step is dedicated to reminders on the thermodynamic concepts already seen, studies of the basic cycles, discovery of the technologies used and training in the use of Thermoptim. It lasts about 12 hours, the time for revisions and complements being excluded.

At the end of this step, you should have perfectly memorized the following knowledge :

• The vocabulary and the basic concepts of thermodynamics.
• The thermodynamic properties of fluids (in a qualitative way) and their correspondence in the various domains of the charts.
• The shape of the main isovalues in the thermodynamic charts.
• The first law, the functions h, Q, W, shaft work, energy balances calculation
• The architecture of the basic examples, their orders of magnitude for a design.
• The shape of the cycles of these examples, at least in the (T,s) and (h, log P) charts
• The differences (in a qualitative way) between the cycles of the examples and the Carnot's cycle, (i.e. The qualitative analysis of their irreversibilities)
• The main technological constraints encountered in these examples.

2) The reinforcement of the concepts seen during the first step , with theoretical complements on exergy and heat-exchangers, and the study of variants of the basic cycles, of combined cycles and cogeneration (about 8 hours of work, complements not included).

At the end of this step, you should have understood the following:

• The typology and the calculation principles of the Thermoptim core components (as well as their technological characteristics).
• For each example, the origin of irreversibilities and the general ideas for improvements.
• The calculation principles of heat-exchangers under the design conditions and in off-design operation.
• The shape of the basic cycles in the (h, s), (xh, h), (xh, s) charts.
• The influence of the design parameters on the performance of the main Energy Conversion Technologies (ECT).
• The influence of the external conditions on the performance of the main ECT.
• The environmental impact of the main ECT.
• The principles for calculating exergy balances.

At the end of this step, you should have acquired the following knowledge:

• configure a quite simple model with Thermoptim and to compute its performances.
• draw its thermodynamic cycle in the adequate thermodynamic charts and to check its consistency.
• design and give the main dimensions of a heat-exchanger.
• find in the technical documentation the technological characteristics of the simple components.
• recalculate from an already defined spreadsheet the exergy balance of one example cycle for a different set of numeric values.

3) The in-depth analyses and the personal applications

These analyses and personal applications will give rise to the study of innovative cycles more complex than the ones of steps one and two. You should also think about the perspective of these technologies during mini-projects that you may lead personally or within a group. (The duration of this step is very dependent on the personal activities selected.)

The first two steps are almost standard, even if their content can vary slightly depending on the profile and prior knowledge of students: they allow students to acquire the bases of the discipline. They consist mainly of Diapason sessions that guide students step by step through the first lessons.

Gradually, as their understanding of the discipline grows, the student gains autonomy and can use complementary digital resources, such as those of the Thermoptim-UNIT portal.

During the third step, students can customize their curriculum based on their interests and aspirations, and access methodology guides explaining how to tackle more difficult subjects. While previously they had very little interest in the internal functioning of components and in their behavioral equations, they can if they wish start developing their own models by customizing the basic components available, or creating others.