HHH
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CYCTHERM
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MATERIAL & ENERGY BALANCE AND 2nd LAW ANALYSIS
COMPONENTS Source Sink Gas Turbine Mixing Condenser Cooling Tower Gas Compressor Excharger Combustion Chamber Splitter Generic Exchanger HRSG Closed Feedwater Open Feedwater Pump Mixer Surface Condenser Steam Turbine Throattling Valve Boiler Geothermal Turbine Flasher Gas Saturator Fictitious Source Flow Control Null
OPERATING MODE
Direct Implicit Scenario
Ideal Gas Moist Air Mixture of Steam and Ideal gas
Water Refrigerants R22 and R134a
Ammonia Carbon Dioxide Methane Water & Ammonia Solid and Liquid fuels
SYSTEMS
Refrigeration Air Conditioning Gas Cycles Steam Cycles Combined Gas&Steam HAT Kalina
A Software Program for Modelling
Thermodynamic Systems |
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CYCTHERM is a software program for modelling thermodynamic systems, suitable also for those structured in complex cycles. CYCTHERM carries out the thermal balance and performs the 2nd Law analysis using the concept of exergy, that is implemented with the more advanced engineering methods.
CYCTHERM recognizes a set of elementary processes like combustion, expansion, compression, mixing etc. that are called components and in the reality are implemented by specific hardware like combustion chambers, boilers, turbines, compressors, pumps etc. A system is made by one or more components connected together to perform a process. The program uses the process flow diagram to represent the system. A Windows based graphic interface makes easy and fast the drawing of complex flow diagrams. After having drawn the flow diagram and fixed the process parameters, CYCTHERM solves the equations governing the mass and the energy balance, then carries out the exergetic analysis. CYCTHERM features an open architecture that makes easy the extension of the program to deal with new components and new fluids.
Drawing the Process Flow Diagram
When you start CYCTHERM the screen of your PC shows the main window of the program where you may draw the process flow diagram. The current version of the program put at disposal of the user 25 components that allow the simulation of the major part of thermal processes. The components are represented by frame or by icon. To draw the flow diagram recognize which are the components of the program that simulate those of the real process. Open the list of components and select that you need. To connect functionally a component to another, recognize the gates of components to be connected. Consider first the component upstream, point the gate to be connected with the mouse and click. Consider then the component downstream, point the gate to be connected to the component upstream and click. A dotted line, made by three segments that connects the two clicked gates, is displayed. You have many options for customizing the drawing of the flow diagram: you may change the colours of the background and of the components, you may change the style, the shape and the colours of each connecting line. You may select the size of the symbols used to represent the components and the arrows, you may as well translate and resizing your drawing.
Fixing the Operating Conditions
The operating conditions of the process are defined fixing the process parameters and the control parameters. The process parameters are attributes of the components that determine the component performance. The control parameters specify how the calculation is carried out.
Fixing the Control Parameters
The control parameters are those specifying how the calculation is carried out. Among them there are the number of iterations and the environmental conditions. The standard mode of operation of CYCTHERM is the direct or explicit performance mode. This means that the user must specify the properties of all the materials entering the process, in addition to the parameters that control the performance of components, and the program solves the equations governing the mass and the energy balance. You may also solve implicit problems activating a specific option of the Control Parameters or/and you may carry out a sensitivity study.
Analysing the Results
You may access the data generated during the execution of the program with specific procedures that facilitate the interpretation of results, but you may as well access directly the ASCII files where data are stored. You may sort the results according to the four criteria called: Component, Connection, Global, Exergy accounting. Selecting Connection you may look at the properties of the material streams in the connections of the flow diagram; selecting Component you access the properties of the materials streams at the inlet/outlet gates of the components. You may display over an appropriate thermodynamic diagram the physical state of the fluid flowing through a connection or the physical states of a same fluid in many connections. You may use Temperature-Entropy or Enthalpy-Pressure diagrams for two phase, single component, real fluids or other appropriate diagrams for different fluids. Double clicking a point of the T,S diagram you may calculate the fluid properties of that point. Other graphic representation of the results are available: you may draw the Temperature vs. Heat duty diagram for the components Closed Feedwater, Surface Condenser and Heat Recovery Steam Generator or you may draw cartesian graphs of selected entities while analysing the results of a sensitivity study.
CYCTHERM recognizes a wide family of materials that includes the ideal gases as well the moist air passing through the mixtures gas-water and a few of real two phase fluids as for instance the water, the refrigerants, the carbon dioxide etc. Obviously CYCTHERM recognizes the more common fuels and also the two components, two phase mixture water-ammonia. Such wide a family and the modular structure of the program allow the simulation of many types of processes; among them are those thermoelectric, conventional and not as the HAT and the Kalina cycles. CYCTHERM solves direct and indirect (implicit of the type If..Then) problems and solves also scenario or sensitivity analysis.
CYCTHERM is useful in the conceptual design phase of a process and in the optimization studies. It may also be used to assess the performance and the improvements of an existing process. It can be used also as educational tool at university level in the field of thermodynamic of systems.
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