Last Updated: 6/11/08
Free Excel/VBA Spreadsheets for Thermodynamics:
Rankine Cycle, Brayton Cycle, Otto Cycle
If you click on any of the entries below, that Microsoft Excel workbook will be downloaded to your computer. Each of them involves at least one module written in Visual Basic for Applications (VBA), Excel's macro language. All were written under Windows, but should work under MS Office running on a Macintosh. Earlier versions of MS Office on both platforms may not support all features used in these workbooks.
Disclaimer
No warranties, expressed or
implied, are made that these programs are free from error, or are consistent
with any particular standard of merchantability, or will meet your requirements
for any particular application. These programs should not be relied on for
solving problems whose incorrect solution could result in injury or lost
property. If you use these program in such a manner, it is at own risk. The
author disclaims all liability for direct or consequential damages resulting
from your use of these programs, i.e., SOFTWARE THAT IS FREE HAS NO GUARANTEE!
Each of these Excel workbooks contain at least one macro written in Visual Basic for Applications, so that when you open one of them you will probably see a warning like, "[filename] contains macros. Macros may contain viruses. It is always safe to disable macros, but if the macros are legitimate, you might lose some functionality." Then you are given the choices: "Disable Macros", "Enable Macros" and "More Info". In the case of these spreadsheets, you must select "Enable Macros" or they will not work at all! (If you not even offered this choice, then your security is probably set at "High." You must have your security level in Excel set at "Medium" first, before you even open the workbook. This allows you to "choose whether or not to run potentially unsafe macros.") My virus checker is set to update automatically every day (yours should be too!). You should scan these materials (and anything else containing macros you download from the Internet) before opening them, but then you MUST enable macros!
Brayton Cycle (Cold
Air Standard) Template (Updated 6/11/08 to include Regeneration)
This spreadsheet
provides a template for analysis of the Brayton Cycle using the Cold Air
Standard (constant specific heats).
The user must fill in the data in the top grid. From that data, the cells in the second
grid are updated, and Pressure-volume and Temperature-entropy diagrams are
generated. Make sure your volume is
set up high when you open it!
A second sheet in the same workbook (not seen below but operating in a
similar fashion) is set up to include Regeneration.
Rankine Cycle Template (New 5/24/07)
This spreadsheet
provides a template for analysis of the Rankine (Steam) Cycle. The user must fill in the data in the
top grid (from other software or table lookup). From that data, the cells in the second
grid are updated, and Pressure-volume and Temperature-entropy diagrams are
generated. If you use the
thermal properties Excel add-in from Spreadsheetworld.com, then you can have
the whole spreadsheet update whenever any input parameter is changed.
Otto Cycle Template
(Brand New 8/22/07)
This spreadsheet
provides a template for analysis of the Otto (spark-ignition, internal
combustion) Cycle. The user must fill
in the data in the top grid (from other software or table lookup). From that data, the cells in the second
grid are updated, and Pressure-volume and Temperature-entropy diagrams are
generated. If you use the
thermal properties Excel add-in from Spreadsheetworld.com, then you can have
the whole spreadsheet update whenever any input parameter is changed. Turn up your volume before opening!
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