Educational method presentation
At first, we precise that our main educational target is to make our students competent for studying innovative energy powered systems. This implies the following capacities :
a clear mastering of the theoretical basis
a deep knowledge of the technological aspects (existing realizations, main requirements),
the ability to conceive and design innovative thermodynamic cycles.
Regarding the difficulties resulting of the classical approach in thermodynamics, we were led to introduce a new pedagogy.
This completely new approach is developed hereunder. Its main points are described in our communication paper for the TICE 2006 symposium (in French only), (which took place in Toulouse from 21th to 23th of October, 2006).
A new pedagogy looking at thermodynamics with three complementary dimensions
Today, it is very common to refer to a triangle when thinking to pedagogy. This particular educational triangle would have as vertices : the student, the teacher and the knowledge.
This analysis underlines the three following pedagogic classes :
The acquisition class is related to what learns and understands the student.
The content class is related to the manner the teacher defines what he is teaching.
The relationship class is centred on the couple teacher/student.
One of the main interests of this triangulation is to clearly remind that we should not restrict the pedagogic approach to a single dimension, even if some teachers have tried to do it in their pedagogy, explicitly or implicitly.
The educational triangle
Our new approach to thermodynamics education concerns clearly these three dimensions :
regarding the pedagogic aspect of the acquisitions, our work follows the recommendations issued by the well-known and famous theorists of cognitive sciences and constructivism (see our references below). We have essentially looked for a reduction of the learners' cognitive load. This was done by discharging the learners of most of the calculation difficulties they used to face.
As it will be shown later on, our approach regarding the pedagogy of contents corresponds to a radical change of paradigm : instead of using an axiomatic presentation of thermodynamics, we propose that the learners should begin with a qualitative approach of the systems by assembling elementary components. When the students have reached a sufficient culture of the thermodynamic field, we then introduce them to the way we write down some rather complicated equations. Using a software simulator, we moreover cancel the necessity for students to learn the very details of the calculations of the fluids properties. These evolutions lead to modify in-depth the contents to be taught. We propose to organize this content according to a model called RTM(E).
Moreover, using our approach, a monitoring of students in a more personal manner may be easily put up. In a general manner, they face partly online work which may be done alone or within a group, and partly collective lessons in a room with a teacher. During the time dedicated to online work, an individual tutorial may easily be put up if necessary.
From there results a new educational method that we present here in its main points :
The general context of the engineers training
The difficulties faced when teaching applied thermodynamics
The advantage to use the Thermoptim simulator to overcome a first educational difficulty
A second educational difficulty: the teaching of the technological reality
The educational interest of the Diapason modules
The gradual approach which is proposed in three steps
Putting up the detailed monitoring of the students
Some references on education
About the general context
The context of the engineers’ training has highly changed during these last years, though their scientific and technical knowledge and even their capacity to use them to solve real-life problems, are in the specificities which make them more distinguishable from other executive managers. More and more, they have to be concerned with the non-technical dimensions of projects, i.e. with men management, projects balances, products marketing, environmental impact of the technologies. Under such conditions, the times for their commitment in technics is now far more reduced than yesterday.
Moreover, the duration dedicated to technical questions in the engineers’ training program is decreasing progressively. Projects and tutored works are the first victims of this trend.
This evolution in the training specification binds us to renew our pedagogies. But, luckily, we have now a great advantage in the existing virtual environments.
Though the science of energy powered systems may be considered as an old one - its basic concepts have been defined more than 100 years ago -, this science however now continues to develop due to the existing improvements in materials, in remote control, or as a result of the physical and geopolitical constraints on resources.
Moreover, the evolution of the present regulations requires the development of arrangements and systems more and more respectful of the environment. In the next decade, we are expecting huge technological improvements. These huge improvements will require the competences of specialists in applied thermodynamics. Indeed, in the future, it will be necessary to develop and design new integrated cycles with high efficiency and low environmental impact.
Our target is to train our students as well as we can so that they may face these challenges with success.
Difficulties met when teaching applied thermodynamics
It is well known that thermodynamics is a very difficult subject to be taught. This problem has been identified for a long time, and numerous efforts have been done to remedy the question. And until yesterday we were still lacking of solutions, despite efforts from the professors and evolutions in the programs.
The link between theory and applications, which is essential for a good understanding of any scientific question, is very less simple and very less intuitive in thermodynamics than in other fields of physics. In the classical approach of teaching applied sciences, such as electricity or mechanics, theory and applications relative to simple examples are simultaneously presented to the students. It is generally possible to set the pupils some practical works. The pertinence of simple models (U = R . I, equilibrium of forces) is then easily demonstrated and the link between theory and technology appears clearly.
Consequently, we are usually talking about elementary physics laws, though there are only directly intelligible models which may explain how run a lot of very useful and well-known devices (electric bulb, heating resistance, simple machinery such as a winch, a hoisting gear, a sloping gangway, a pendulum ...).
As for energy systems, it is quite always impossible to find simple and precise models. Without almost any rough consideration, we may say that the classical approach of thermodynamics leads to this dilemma : the proposed models are either not realistic or not calculable. Thus, these two difficulties result in unmotivated students :
Considering these approaches, and regarding the difficulties for an accurate and precise calculation of the properties of thermodynamic fluids, we are then generally induced either to assume hypotheses which simplify too much the problem, or to embrace methods which are very dull in their application. For instance, in almost every program of the junior college or graduate school at university around the world, the internal combustion motors are analysed assuming the technical fluid is air. And this air is supposed to be a perfect gas. As for calculations about refrigeration cycles or steam cycles, they are done using either numerical tables by means of uneasy interpolations, or by charts which are not very accurate.
When the hypotheses simplify too much the question, the students do not understand the practical meaning and the interest of the models they are building up, because these models are too unrealistic.
On the other hand, the accurate and precise calculations are so dull that they are disgusted with applied thermodynamics.
If there are such limitations in the classical approaches of the field, this is due, according to our opinion, to a very recent past, where the engineers could use only their slide rule and their logarithms tables. This is also due to the fact that the classical approaches have not been changed for several decades.
Use of the Thermoptim simulator to overcome a first pedagogic difficulty
It is possible to overcome the difficulties met with the classical approaches if we notice that Thermodynamics is far much simpler from the qualitative point of view than from the quantitative one and also if its pedagogy is renewed through a frequent use of simulators to do the calculations.
The use of the Thermoptim software results for a student to become familiar with the energy systems by exploring or assembling himself the models related to the main energy conversion technologies. The energy conversion is modelled as an assembly of various components fed by thermodynamic fluids. Each thermodynamic fluid gets out of its relevant component in a different thermodynamic state. To simplify the approach, we may adopt the following double approach: in a first step we consider only a quite simple and global perspective of the energy system, then, we may study each component to understand the thermodynamic phenomenon involved.
The global representation is quite useful in a qualitative way : it can be drawn visually and we may then clearly understand the need for each component in the global representation of the system. In an educational way, the global representation is essential to clearly understand the design rules of these technologies. Besides, when the internal structure of a motor or a refrigeration system is clear in our mind, then the study of each component involved is easier because we understand better how it fits in the global system and what is its contribution to the whole.
This distinction between the components of a system and the system itself is an important point of the pedagogy we recommend. The more reduced is the number of the most commonly used thermodynamic components, the more numerous may be the systems that can be imagined from their assembly. Regarding the possible thermodynamic systems, a still large field remains to be investigated in the next decades.
Refrigeration machine in Thermoptim
Regarding the components (compressors, adiabatic expansion mechanical converters, with or without thermodynamic work, heat-exchangers, combustion chambers...) students have to understand clearly the processes undergone by the fluids flowing across them. Moreover, they have to be particularly able to link the used technologies and the basic hypotheses assumed for their modelling. (For instance, a heat-exchanger or a combustion chamber are roughly isobaric, a compressor or a turbine are generally adiabatic.)
Thermoptim can simulate a great number of systems: the simpliests, such as the the refrigerator shown hereabove which is a basic example in the thermodynamic science.
The Thermoptim structure
The main pedagogic innovations brought by Thermoptim are the following:
First of all, if the long and dull calculations are cancelled and most of the quantitative aspects are transferred to the computer, students have more time to train in thermodynamics.
Thermoptim is based on the distinction of some elementary concepts, called primitive types, whose structure shown hereabove helps the students to understand clearly the inter-relations.
Using Thermoptim, the beginners learn the vocabulary and the basic concepts encapsulated in the displayed windows whose design has been very carefully developed making sure that their content is as simple as possible. Once the vocabulary is known, the cooperative learning with others students and the teacher is intensified.
The synoptic diagram editor gathers in a synthetic manner, on one screen, all the pertinent informations about one thermodynamic cycle. (On the synoptic view are displayed : the graphic structure of the system, the inter-connections between the components, the values of the thermodynamic state variables, the global energy balance of the system...)
Thermoptim is not only a very good courseware: its functionalities indicate that it is also a powerful and professional simulator. In fact, Thermoptim is used by some manufacturers such as EDF, CEA or Areva.
Thermoptim puts the students' mind in a superior conceptual and methodological level, because all the calculations are discharged on the computer. Therefore, there is not only a reduction of the cognitive load, but also a significant increase of the capacity to solve problems.
At last, Thermoptim makes students truly operational. This is an important element in their motivation and consequently in their attention.
If we have on our computer an adequate graphic environment as the Thermoptim diagram editor, the internal structure of a system may be shown without any difficulty. Thus, we get a qualitative representation very easy to understand. This representation is then to be quantified firstly by an adequate parametrization of the thermodynamic properties of the various components and secondly by calculating them. Besides, this qualitative representation is usually not dependent on the hypotheses assumed for the calculation of the various components. This representation is an invariant of the system.
A second educational difficulty: the teaching of the technological reality
A second educational difficulty is the teaching of the technological reality. In order to get round the difficulties which the teaching of thermodynamics traditionally faces, the knowledge to be taught have been deeply reorganized in compliance with a model called : RTM(E) , standing for : Reality Theory Methods (Examples). The presentation of the methods and the examples is now based on the use of a simulator. This avoids students to be overloaded with equations and dull calculations.
Since the question of the calculations is now commonly solved by the use of software tools, the presentation to the students of what we call the technological reality is, in our opinion, the main residual difficulty.
More than half of the course duration is dedicated to the description of machines, their running principles and to the existing technological requirements.
This difficulty is reinforced in the in-class classical method which appears tiring for teachers as well as students, particularly if the course sessions are merged over several consecutive hours.
We had to complement Thermoptim because the software is well adapted to teach the Methods and the Examples, but not at all adapted to learn neither the technological Reality nor the Theory. To overcome these difficulties, we have developed in the year 2004 some e-learning modules provided with a soundtrack called Diapason. These modules gather in a concise way all the informations the students need to learn and make them available to them at any time.
The Diapason modules
The Diapason modules are educational animated slide shows, each provided with a soundtrack. This is Information and Communication Technology (ICT) applied to education. Using this ICT application, you may realize presentation for theories, or methodologies or technologies.
Their specificity is the association of one soundtrack to the displayed window. Thus, students may get audio explanations relative to the study context ; these explanations may be about theory, or technology or even the practical use of the Thermoptim simulator. An online presentation of these modules is available.
These modules are structured in steps and sessions as well as in courses and programs. From this, results the large possibilities in the conception of rich educational environments. Hyperlinks may give you access to various documents such as spreadsheet documents or files in pdf format.
Based on double xml structure, the DIAPASON modules use as visual display a freeware Flash execution application supported by almost all the recent Web navigators, which makes it possible to synchronize varied multimedia resources (images, sound tracks, pdf documents, swf animations, spreadsheets, hyperlinks, Thermoptim...).
The principal interest of the Diapason modules is their excellent teaching effectiveness:
When using these modules, the students are more active than in course room, in the sense that they regulate themselves their rhythm of listening, but especially they choose themselves the moments when they study, and are thus available when they do it; they learn better, more especially as they have any leisure to retrogress or to supplement information which is presented to them while resorting to the written documents.
The sound tracks having an average duration of less than one minute, their attention can be constant when they study a step, and they pass to the following only after a rest period.
The students can work at their rhythm, alone or in groups, and they have access constantly at the oral explanations given by the teacher: in case of doubt or if they missed, they can refer to it without any difficulty.
To facilitate the conception of these modules, we have written a xml file builder . Written in JAVA, this xml file builder has a user-friendly interface. It is free for downloading.
Since 2016, the French version of these Diapason modules have been supplemented by videos (about sixty for applied thermodynamics and about sixty for global energy problems).
A three-stepped progressive approach
It is our opinion that learning is an iterative process, which fits well with a progressive pedagogy. This progressive pedagogy goes from the simple but realistic concepts (necessarily!) to the more complicated ones. For some reasons, maybe cognitive, maybe psychological, it is better in the beginnings to show the students how the proposed knowledge may be put into practice. This may be done putting aside as much as possible the conceptual difficulties.
These reasons about the pedagogy are particularly true in applied thermodynamics. Let us remind you that the students must be familiar with a new technological reality. A new reality which they do not even know. Consequently, this learning already results in a high cognitive load.
At the beginning, we deem it better to show the students the existing environments such as Thermoptim with which they may study thermodynamics easily and get very precise and accurate results without writing any equations. Once their initial hesitations have vanished, and once they have assimilated the vocabulary and the basic concepts, it becomes possible to step forward and to introduce additional equations. For a decade, we have had experience with the following behaviour of students: when they realize the existence of powerful methods to get a realistic application, though they were highly hesitating concerning the theory, they ask for in-depth analyses of the theory.
As soon as have vanished the psychological blocks resulting from an axiomatic presentation of thermodynamics which can't get into practise, the students become receptive toward equations. Probably, because they no longer fear to be unable to get them into practice. Thus, many wish to know more and understand clearly how the calculations are done.
A deep analysis and discussion about the simulators pedagogic use in teaching and about the very controversial topic related to equations to be discovered and learned by students, has been presented in an invited paper during the SIMO seminar (SIMO : Informative System, modelling, optimizing in monitoring and remote control in the field of process engineering. : "Virtual reality and daily reality" Toulouse October, 11th-12th 2006).
According to feedback coming from students familiar with the Diapason modules, it appears better that they should be set a three-stepped gradation in learning:
The learning of basic concepts and tools, dedicated to remind thermodynamics basic concepts, to study basic thermodynamic cycles, to discover the used technologies and to learn how to use Thermoptim.
The reinforcement of the concepts viewed in step one, with theoretical complements concerning exergy and heat-exchangers, the study of variations about basic cycles, about combined cycles and about cogeneration.
The in-depth analysis and personal practice regarding the study of innovative cycles and some thoughts about the future of these technologies. These deep analysis and personal practice will concern mini-projects led alone or within a group.
For instance, you may consult the self-training module related to energy powered systems . It will show you how these principles may be brought into practice.
Detailed monitoring of students
Resulting of the existence of the Diapason modules, the students are now working partly on line and partly in a classroom with a professor. The student's attendance in the classroom is required compulsory. Besides, the time dedicated to each kind of learning depends on the context.
Of course, a high flexibility in the timing results in some risks, such as some loose devotion to work. It is then necessary to set in a precise monitoring of the students. It is also necessary to boost them without any hesitation by email and to remind them to progress in their work.
At the beginning of the course, a card-paper indicating on both sides the pedagogic targets is delivered to the students. This card marks off which knowledge is to be perfectly memorized, which knowledge is to be clearly understood and which skills are be acquired.
It is our opinion that the best evaluation test for students is an oral examination in addition to a little personal project realized in groups of two.
The oral examination checks in less than 15 minutes that each student really has memorized some basic concepts, such as the sketch of elementary cycles, their graph in the usual referentials. It also checks that the student has understood the bases of thermodynamics. The project which is led inclass with under tutor supervision must check that the student is able to put into practice in a proposed practical example the knowledge acquired.
Construction or directed exploration of models?
A tool like Thermoptim allows one to complete a classical teaching of thermodynamics by a wide variety of educational activities, which can be grouped into two main categories:
those of discovery and initiation, notably by exploration of predefined models
model construction, which involves students seeking to learn to model energy systems by themselves.
From 1998 to 2016, the main use of this tool in higher education corresponds to the second category. It allows learners to get to the bottom of things and to learn to build themselves different thermodynamic cycles, and thus gives them a great deal of autonomy, a motivating factor, especially when they are on internship.
However, it assumes that their first steps to use the software are the subject of tutorials requiring supervision by teachers mastering the tool, some manipulations requiring a minimum practice.
For other educational contexts, the first category has many advantages. To reduce the difficulties associated with the use of the software package, learners do not build the models themselves, but explore and parameter models already built.
The scenario is presented in a specific Java browser able to emulate Thermoptim, which offers different activities to learners, such as finding values in the simulator screens, setting its parameters, performing sensitivity analysis... Contextual explanations are given gradually.
Directed explorations are defined in a html file 5, which allows the student to open and close Thermoptim files corresponding to the studied models, to plot the cycles in the thermodynamic diagrams, and to propose small quizzes to the learners so that they can check their understanding of the methods used.
This ensures that they do not waste time on handling errors that are not of pedagogical interest, which is essential for their work to be done within the allotted time. The risks of error are greatly reduced, and if they do occur, learners simply have to reset the browser by reloading the files they use.
For example, in the MOOC Thermodynamic Conversion of Heat (in French), the simulator is mainly used in the form of about twenty directed explorations of existing models.
A book Energy Systems: A New Approach to Engineering Thermodynamics has been published by CRC Press.
The reader is explained how to build appropriate models to bridge the technological reality with the theoretical basis of energy engineering.
This volume is intended for courses in applied thermodynamics, energy systems, energy conversion, thermal engineering to senior undergraduate and graduate-level students in mechanical, energy, chemical and petroleum engineering. Students should already have taken a first year course in thermodynamics. The refreshing approach and exceptionally rich coverage make it a great reference tool for researchers and professionals also. Contains International Units (SI).
References about pedagogy
We have gathered some bibliographical references and some internet addresses which were very useful to think out our pedagogic project about thermodynamics. The list is obviously far from being exhaustive. But it may be a useful introduction for other professors and colleagues.