**Last Updated: 3/21/2019**

**Brayton Cycle (Cold
Air Standard) Template including Regeneration (Updated 3/22/2018)**

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. For photos of
aircraft powered by the Brayton cycle (Turbofans and Turboprops) as well as
some powered by the Otto cycle, click here.

**Rankine Cycle Template (Updated 6/18/2018)**

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. For best results
download the handy Excel “add-in” from Coolprop. That easy-to-implement add-in provides
functions for all the properties of water you’ll need in completing this
spreadsheet (and those of 150+ other fluids as well). The logic is not much different that
manual table look-up and interpolation – provide two independent
properties, e.g., P and Q (quality) and the function returns any of the others
(U, T, H, S, etc.) Once you
have implemented these functions properly, then the whole spreadsheet will
update whenever any input parameter (those having the green background in the
screen grab below) is changed.
This spreadsheet includes a VBA function that (assuming you’ve
automated the property evaluations using Coolprop or
something similar) allows you to run a sequence of cases automatically to
assess the sensitivity of one variable, e.g., the cycle efficiency, to another
parameter, e.g., the turbine inlet pressure.

**Otto Cycle****
Template (Updated 3/27/2018)**

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 CoolProp, then
you can have the whole spreadsheet update whenever any input parameter is
changed. This updated spreadsheet
includes the capability of doing a sensitivity analysis. Turn up your volume before opening! For more on large aircraft
engines using the Otto cycle, click here.

**Diesel Cycle
Template (Updated 3/15/2018)**

This spreadsheet provides a template for analysis of the Diesel
(compression-ignition, internal combustion) Cycle. 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. This
workbook includes the capability of doing a sensitivity analysis.

**Humphrey
Cycle (New 5/3/2018)**

You won’t find the Humphrey cycle in
your thermo book. It involves a slight (in theory)
modification to the Brayton cycle. The heat is added at
constant volume instead of constant pressure. Thus the temperature rise in the
combustion step is a factor of the ratio of specific heats higher than in the
Brayton cycle. You will find that
the increase in entropy is lower than that in the Brayton cycle and the cycle
efficiency is correspondingly higher. If the practicalities can be
worked out, the Humphrey cycle will be a “game changer.”

**Vapor-Compression Refrigeration
Cycle (New 5/2/2018)**

** **The vapor-compression refrigeration cycle
is analogous to the Rankine cycle, but runs in the opposite direction
(counter-clockwise on the TS diagram vs. clockwise for the Rankine power
cycle). This template uses
R-134a as the working fluid, but can be readily changed to another refrigerant.

**Mollier Diagram (New 6/5/2018)**

** **The Mollier
Diagram provides a useful way of depicting states and processes in a graphical
format. This workbook for water
allows you to plot points (obtained using the CoolProp
Excel add-in directly) on a Mollier-Diagram found
online at engineeringtoolbox.com.
In theory you could use the CoolProp functions
to create your own Mollier diagram from scratch, but
Excel won’t allow you to plot that complicated a data set.

**ProperT (New 10/23/2018, Version 2.0)**

** **The workbook uses the Coolprop
Excel add-in to compute thermophysical properties of
a baker’s dozen of fluids. The
user can then plot the saturated liquid and saturated vapor lines in one of
four common formats: (1) Temperature – entropy, (2) Pressure –
volume, (3) Temperature – volume and (4) enthalpy – entropy (Mollier diagram). Using the model of Coolprop’s TextExcel.xlsm, this new edition includes
a property calculator that uses units and nomenclature more frequently
encountered in the study of engineering thermodynamics (kPa,
kJ, specific volume, etc.). If you
are analyzing a thermodynamic process or even a complete cycle, you can save
the data returned by the property calculator and add it as another data series
to the existing plot.

Back to Spreadsheets Main Page

Back to Heat Transfer
Tools Main Page

9/24/2018