State Daemons - Smart State Calculators   Ten Classes of Working Substances The TEST database covers almost all frequently encountered thermodynamic working substances. They are divided into nine categories according to the underlying model: 1. Pure Solids/Liquids; 2. Pure Perfect Gases; 3. Pure Ideal Gases; 4. Pure Real Gases; 5. Binary Perfect Gas Mixtures; 6. Binary Ideal Gas Mixture; 7. Binary Real Gas Mixture; 8. Moist Air; 9. General Gas Mixtures; and 10. Phase-Change Fluids.  Full-size image Visual Calculator Enter the known properties in any available units and click the Calculate button or press the Enter key. If sufficient information is provided, the state is fully calculated. For phase-change fluids, the phase composition is evaluated as part of the state. If the information provided is incomplete the state is partially evaluated. In addition to thermodynamic properties, the description of State includes a number of useful extrinsic properties such as total energy, total enthalpy etc., a few system properites and relevant material properties. Different colors are used to represent different groups of state variables.  Full-size image Algebraic Expressions and Thermodynamic Plots Microsoft Excel-style algebraic expressions can be used in entering a state variable. This feature is particularly useful in evaluating states, which are related. In evaluating State-2, isentropic to State-1, you enter =s1 for s2. To draw a thermodynamic plot with the calculated states, simply choose a plot type from the plot menu.  Full-size image Built-in Scientific Calculator Need to calculate the area of cross-section of a pipe, or a difference between enthalpies of two calculated states? The Message Panel, where tips and error messages are displayed, also doubles as a full-fledged scientifc calculator that also accepts property symbols. Simply move the pointer over to the Message Panel and the Calculator is activated. Type in an expression - 3.14*(10*2.54/100)^2, h2-h1, (u2-u1)/(v2-v1) - and press the Enter key. Full-size image Error Checks and Other Smart Features The daemons (calculators) prevent you from entering redundant input, say v3, after p3 and x3 have been entered, by turning off the dependent variables with appropriate warning displayed on a message panel. To obtain a definition for the variable a widget represents, hover the pointer over it at low speed. Different background colors are used in state variables: pink when disabled, yellow when enabled, green after a variable has been read from the direct input, turquoise when evaluated from state equations, gray when imported from the Analysis panel, and white to indicate syntax error or unfinished evaluation. Full-size image Data Extrapolation TEST uses reasonable approximations in extrapolating data beyond the available range. For instance, the superheated vapor data is extrapolated using the ideal gas model, the ideal gas data is extrapolated using the perfect gas model, and so on. This extrapolation scheme makes TEST robust at the expense of precision at extreme values of properties. Full-size image Mixed Units and Global Unit Change Work with any combination of units. Once a solution is complete click on the SI or English radio button and Super-Calculate the entire solution to convert units globally. All the states are updated to the new choice of unit system. A detailed output is also generated by the Super-Calculate operation on the Input/Ouput panel. Full-size image What-If Scenarios Once a solution is complete, the effect of a change of variable on the solution can be easily determined. Simply change the value of the variable to a new value, Calculate to register the change and Super-Calculate to generate the new solution. The working fluid is also a legitimate variable. In a complex refrigeration cycle, for example, the refrigerant can be changed in a parametric study. Full-size image Spreadsheet Friendly Output  TEST provides limited amount of graphics capabilities. For sophisticated plots or further post-processing, you may like to export TEST results to a spreadsheet. Part of the output generated by the Super-Calculate operation is a spreadsheet friendly table of state variables. You can copy and paste the table on almost any spreadsheet software, the columns are tab-delimited. Full-size image TEST Codes Finally, a Super-Calculate operation produces a series of instructions, called the TEST-Codes, which can be used to regenerate the solution instantly. TEST-Code can be copied and saved as a text file using any word processor (such as Notepad). TEST-Codes not only provide a mean for storing and sharing a visual solution, but its simple syntax converts a complex problem into a few lines of simple statements. The Codes can be also used to regenerate the solution using a different material model.  Full-size image Loading TEST-Codes TEST Code is a great source to jump start seed cases for what-if studies. You will find a number of such seed cases in the Slide Show, the Tutorial and the Archive. To load a case, copy the TEST-Code onto the I/O Panel of the appropriate daemon, click the Load button and, if loading progresses without any significant error, the Super-Calculate button. The visual solution is instantly regenerated. Full-size image Parametric Study Using TEST-Code TEST Code also provides a simple way to change an input parameter and obtain a new solution. After a solution is achieve, Super-Calculate to produce the TEST-Code on the I/O panel. Change any input parameter on the TEST-Code, Load, and Super-Calculate to update the solution. Repeat! Because the solution report is also displayed here, you do not have to leave the I/O panel to finish a parametric study in this manner. Full-size image Next feature