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To allow users to perform pinch analysis on their own plants as easily as possible, thisfree spreadsheet has been supplied. This performs the key targeting calculations and

plots, as follows:

Input of stream data (either as CP or heat load). Calculation of composite curve data, Problem table, energy targets and pinch

temperature. Plotting of composite curves and GCC. Plotting stream population over temperature range and basic grid diagram. Tables and graphical plots of variation of energy and pinch temperature over a

range of Tmin.

Area and cost targeting is not performed because of the considerable extracomplexity, the frequent lack of suitable data on heat exchanger coefficients, and theflat nature of most cost- Tminplots. Topology traps can still be identified from the

graphs of utility use and pinch temperature against T

min. Most of the composite andGCC in the book have been generated using this spreadsheet. It was written forMicrosoft Excelbut should run in similar compatible spreadsheets; however, fullycorrect operation cannot be guaranteed.

The spreadsheet was the winning entry in a competition run by the Institution ofChemical Engineers for young process engineers, and was written but Gabriel

Norwood.

When the spreadsheet is opened, it takes you directly to the INPUT tab, where thedata is entered.

On the INPUT tab, enter the global min chosen for the problem in cell F6, followedby the stream data. Note that the data must be in compatible units. The defaultspreadsheet display assumes that SI-based metric units are in use, but you can useyour own units and alter the cell headings. You can also choose whether to enter thedata as specific heat capacity and mass flowrate, heat capacity flowrate (CP) or heatflow.Enter the stream data, line by line. As you begin each line, cells requiring input arehighlighted in yellow. Streams can be numbered, named or both. If a stream changesheat capacity significantly over the temperature range, enter each segment separately(e.g. as 3a, 3b, 3c, etc.). Enter latent heat streams by assigning them a smalltemperature difference, say 0.1C.

As data is entered, the spreadsheet automatically calculates the full stream data, whichcan be seen on the right-hand side of the first tab and on other results tabs. The

program calculates whether a stream is hot or cold depending on the differencebetween the supply and target temperatures. All heat capacity flowrates (CP) shouldbe positive, never negative.The furthest left-hand tab, INDEX, gives a list of all the results tabs, with hyper-links.The results tabs are as follows:

TARGETS Problem table, energy targets, pinch temperature and type of problem(pinch, threshold, multiple pinch, or pinch region)CC Hot and cold composite curvesSCC Shifted composite curves

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GCC Grand composite curvesGRID Network grid diagram, shifted temperaturesAS Stream data plot, actual temperaturesSS Stream data plot, shifted temperaturesAT Interval tables (heat loads and temperatures), actual temperatures

ST Interval tables (heat loads and temperatures), shifted temperaturesDTMIN Variation of hot and cold utility targets and pinch temperature with min.

The last sentence of these calculations, varying min over a range, uses a marco andwill not work if your spreadsheet security levels are set to High; therefore, on thespreadsheet menu go to Tools Marco Security and set to Medium (recommended)or Low. To obtain the plots, enter the maximum and minimum value of the requiredrange and the program will then calculate over the range in 20 equal steps of min