Project files

Thermoptim calculations are structured around projects.

You can create a new project or open (load) an existing project. When you have defined the different elements which comprise your project, you can save it by selecting "Save..." or "Save as...".

The list of existing projects can be obtained by selecting "Project library". By double-clicking a line of the project library table, you can open it.

The list of existing examples can be obtained by selecting "Example library". Examples can be loaded and saved in your project directory.

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Result files

"Export results" creates a text file in which detailed results of the project are saved

"Export cycle file" creates a text file which can be read by the Interactive Vapor Charts for plotting the project points

"Export pinch method fluids" creates a text file with the pinch method fluids which can be read by 4D Thermoptim version

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Special

"Interactive Charts" opens a frame allowing you to display the project points in one of the three types of interactive thermodynamic charts (for vapors, ideal gases or psychrometric) and to create project points from these diagrams

" Optimization Tools" opens the optimization frame
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Substances

THERMOPTIM makes use of three kinds of substances: pure ideal gases, composed ideal gases and condensable vapors (which are pure substances). Perfect gases are ideal gases whose specific heat is independent of the temperature.

The substance can be pure, in which case its properties are predefined in the software, or it can be compound. In this case (that is possible only for a gas), the user has to define the composition from the other gases present in the database, by indicating for each of them, its name and its molar or mass fraction. Properties of the composed substance are then determined from those of its constituents.

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Points

A point designates a particle of a substance and allows the user to define intensive state variables: pressure, temperature, specific heat, enthalpy, entropy, internal energy, exergy, and quality. A point is identified by its name and the name of the associated substance. 

To calculate a point, you may either :
- enter the values of at least two state variables, generally its pressure and temperature for open systems, and its volume and temperature for closed systems.
- automatically calculate them by using for instance one of the processes. 

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Processes

Processes correspond to thermodynamic evolutions undergone by a substance between two states. A process associates therefore two points such as defined previously, an inlet and an outlet point. 

Moreover, it indicates the mass flow rate involved, and allows one therefore to calculate extensive state variables, and notably to determine the variation of energy involved in the course of the process.

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Nodes

Nodes  allow you to describe elements of the system where mixes and divisions of fluids take place. In a node, several junctions of fluid are connected to form a single vein.

If the node is a mixer, the various branches join to form a single vein. The mass flow rate of the main vein is equal to the sum of these of branches, and the enthalpy balance allows one one to calculate the mass enthalpy and the temperature of the mixture.

If the node is a divider, the main vein divides into several branches, whose flow must of course be calculated. Its distribution between the branches is set proportional to the "flow-rate factors" specified by you. The temperature and the mass enthalpy are of course conserved.

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Heat exchangers

Thermal heat exchangers connect two fluids, one that gets hotter, the other that gets colder. The most simple definition for a heat exchanger can be made with the identification of the two processes (fluids) that meet.

 The design of the heat exchanger can then be made if you indicates what constraints are set on the flow rates and temperatures (for instance minimum pinch, set value efficiency). 

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Balance

The overall balance of the project can be calculated with the following conventions:

In each process, the energy type allows you to distinguish between purchased energy, useful energy, and other energy (set by default).  

The purchased energy represents the sum of all the energies that must be supplied to the cycle from outside.
 
The useful energy is the net energy output of the cycle, e.g. the algebraic sum of the energies internally produced and spent. 

These two energy types are those that appear in the definition of the cycle efficiency:
efficiency = (|useful energy|)/(purchased energy)

For example, in a Rankine cycle, the purchased energy is the heat supplied to the boiler and the useful energy is the net work output, that is the work output of the turbine minus the work input of the pump. The other energy is that used by the condenser. 

For a refrigeration cycle, the purchased energy is the input power of the compressor, the useful energy is the refrigeration effect (heat removed at the evaporator level), and the other energy is that removed at the desuperheater and condenser levels.














