R-22 and other State Daemons Slide Show

 (If you do not see a Red Task Bar at the bottom of this page, click here to go to the parent page and click on R-22.)
Smart Thermodynamic State Calculator: Refrigerant-22 (R22)
|TEST Home Page> Utility Applets> R-22|

|Intro |Instructions| |Ex.1| |Ex.2|
Introduction:
Welcome to the Smart Thermodynamic Table: R-22 software module, part of the The Expert System for Thermodynamics. TEST is a network of HTML pages with embedded Java Applets that helps users solve thermodynamic problems and perform parametric studies visually without any programming.

The Smart Thermodynamic Table is more than a visual thermodynamic state calculator for refrigerant-22. In this R-22 table a state is visually presented (see the examples below) as a collection of variables (such as p, T, v, h, s etc.). Known variables are entered in any order and in any units (see Fig. 3) and a click on the Calculate button evaluates the states partially or fully (including  phase composition) if sufficient information is entered. The calculated states are auto-saved and can be plotted on a p-V, T-s or other thermodynamic diagrams by choosing a plot-type from the diagram selector (see Fig. 2).

While evaluating two related states (say, two isentropic states), algebraic expressions involving state variables can be used. For instance, to evaluate State-2, isentropic to State-1, one can enter s2 as =s1. Once a series of states are evaluated, updating all calculations for a change in any input variable is a snap. Simply change the value and click on the Super-Calculate (see Fig. 4) button. In addition to update all calculations, a printer-friendly output is generated on the Output window of the daemon (see Fig. 2).
Because all the State variables are exposed, changing one or more input variables and evaluating their effects is really a matter of two clicks (Calculate and Super-Calculate) , making TEST an exciting visual design tool for the What-If people.

A more comprehensive introduction can be found in the Tutorial page and is highly recommended for all users.

The examples below contain images of the R-22 table in action. Once you get a rough idea about how the smart table works, you can start using the real thing by following these instructions.


|Intro |Instructions| |Ex.1| |Ex.2|
Instructions:
There are two ways of doing anything, the quick way and the right way.

If you are in a hurry, do the following: (a) Browse the examples below (takes only a minute), and (b) Launch the customized Java applet (called a daemon) by clicking the appropriate link at the top of this page. If you have a modern browser (Netscape 4.5 or better, Microsoft IE 4.0 or better), the daemon will appear in about 10-50 seconds (1 second if you are running from a locally installed TEST from a TEST-CD) and you can start exploring.

To fully exploit TEST follow these steps: (a) Browse the Slide Show (at least the first 20-30 slides); (b) Start the Tutorial and get a hands-on training on your favorite daemon (do not forget to read both the Theory and Practice pages). (c) Explore a few daemons systematically as explained in the tutorial. (e) Once you understand the TEST algorithm, you can use the TEST-Map to quick-start a desired daemon. (f) If you like using the software, please register (from the Home page) as a courtesy. (g) For better speed and service, acquire a TEST-CD or a site license. Of course, all these may take better part of an hour - but, trust me, you will not regret it.


|Intro |Instructions| |Ex.1| |Ex.2|
Examples : (The working fluid used in the solutions may be different from R-22, but the procedures remains the same.)
Example-1: Determine the enthalpy of liquid R-22 (Refrigerant-22) at a temperature of 20oC. What is the final phase composition (quality) and pressure if the refrigerant is throttled (at constant enthalpy) to produce a temperature of 0oC? 

Solution: To bring up the appropriate daemon (applet) navigate to TEST Home Page, Test, Daemons, States, and R-22 in sequence (or directly using the 'R-22 Applet' link at the top). 

The daemon page will be displayed on the upper frame and a help page will appear on the lower frame of the browser window. As the daemon gets loaded, you may see its shadow for about 5-15 seconds. 

Trouble Shooting: If the daemon (as pictured below) does not show up even after a minute, may be your browser is unable to run Java applications. I know about 4 reasons for that. (i) Your browser has not been updated since the Jurassic age (you need Netscape 4.5+ or IE 4.0+), (ii) Java is turned off, (iii) Security is set to 'high' (in case of Internet Explorer). (iv) Your computer is behind a firewall that filters Java Applets. (v) The connection is too poor for the demanding Java applications to be loaded. Instructions for how to rectify the first three problems can be found in the Help section. For the last two problems, you need a TEST-CD. A TEST-CD will give you native performance with virtually no wait time for loading pages (applets takes a couple of seconds at most as opposed to minutes over the net). 
Image of the smart R-22 table
Fig. 1. Image of the Smart Table (R-22 Daemon) producing solution to Example 1.

Taking advantage of a classical simplification, a Liquid can be treated as saturated liquid (at the same temperature) within acceptable errors. Enter the values of the known variables, temperature and quality (x=0 for saturated liquid) (Velocity and height z are set to 0 by default), and click the 'Calculate' button to obtain the complete state. All the properties have a suffix '1' as the state is identified as 'State-1'. 
 
Image of the smart R-22 table
Fig. 2. Image of the Smart Table (R-22 Daemon) producing solution to Example 1.

Now choose 'State-2' from the state selector, enter the known temperature and enthalpy (note the use of algebraic expression rather than absolute value), and click the 'Calculate' button to obtain the complete state. Note that the phase composition is evaluated as part of the solution. The refrigerant-22 table offers many other smart features like this, some of which are highlighted in the slide show (link at the top margin) and some are left for the users to explore.
 
Image of the smart R-22 table and instructions
Fig. 3. Instructions for calculating a State. More details can be found in the Tutorial section.


|Intro |Instructions| |Ex.1| |Ex.2|
Example-2: How would the answer in Ex. 1 change if the initial temperature is 50oC instead?

Solution: After Example 1 has been solved, simply change the temperature T1 in State-1 to 50 C, click the 'Calculate' button to register the change and then the 'Super-Calculate' button to update all calculations. The ease with which a parametric study can be performed without any programming is one of the many features of the R-22 smart table. Some of these features are highlighted in the slide show (link at the top margin) and some are left for the users to explore.
 
 
Image of the smart R-22 table
Fig. 4. Image of the Smart Thermodynamic Table (R-22 Daemon) producing solution to Example 2.

These examples are only meant to give the reader the flavor of a daemon (applet). For a systematic exploration of TEST, start with the Slide Show, then the Tutorial and then start solving problems.

|Intro |Instructions| |Ex.1| |Ex.2|

Copyright 1998-2002: Subrata Bhattacharjee