The steam tables application calculates 32 thermodynamic and transport properties of water and steam. It allows 16 different combinations of input variables to be used for calculations.

Input variables that can be used are:

- Pressure
- Temperature
- Enthalpy
- Entropy
- Volume
- Internal energy
- Steam quality

The application uses a new industrial formulation for steam tables, called "IAPWS Industrial Formulation 1997 for the Thermodynamic Properties of Water and Steam (IAPWS-IF97)", and replaces the previous industrial formulation, IFC-67. IAPWS-IF97 significantly improves both the accuracy and speed of the calculation of thermodynamic properties compared with the old formulation. For transport properties calculations are based on the latest internationally accepted equations also available from IAPWS.

The application also enables calculation of thermodynamic and transport properties of water and steam based on the Scientific Formulation **IAPWS-95**. This is the most accurate formulation for calculating properties of water and steam available today.

In 1995, the International Association for the Properties of Water and Steam (IAPWS) adopted a new formulation for the thermodynamic properties of water and steam for general and scientific use, called:

- "The IAPWS Formulation 1995 for the Thermodynamic Properties of Ordinary Water Substance for General and Scientific Use"

This new formulation, called **IAPWS-95, provides the most accurate** representation of the thermodynamic properties of the fluid phases of water substance over a wide range of conditions.

IAPWS-95 is a fundamental equation of Helmholtz free energy as a function of temperature and density, which yields other thermodynamic properties by differentiation and algebraic manipulation without the use of any other information. IAPWS-95 defines accurately the thermodynamic properties of ordinary water substance, with complete thermodynamic consistency between these properties, over a wide range of states. Thus IAPWS-95 is recommended as the source of the thermodynamic properties of water and steam. However, since the independent variables of IAPWS-95 are temperature and density, computing times for some applications may be excessive. Because of that IAPWS-IF97 was developed, to provide almost as accurate results, but at a much faster speed.

In 1997, the International Association for the Properties of Water and Steam (IAPWS) adopted a new formulation for the thermodynamic properties of water and steam for industrial use. This new formulation, called:

- "The IAPWS Industrial Formulation 1997 for the Thermodynamic Properties of Water and Steam (IAPWS-IF97)"

The new Industrial formulation replaces the previous industrial formulation, IFC-67, that had formed the basis for power-plant calculation and other applications in energy engineering since the late 1960's. IAPWS-IF97 improves significantly both accuracy and speed of the calculation of the thermodynamic properties compared with IFC-67.

The driving force behind the development of the new formulation was increased computing speed. This effort was promoted by the power industry, which makes extensive use of steam properties in preparing power cycle calculations.

There are a number of important advantages which IAWPS-IF97 has over the old industrial formulation IFC-67, these include:

- Improved Consistency at Interregional Boundaries
- Better Agreement with Scientific Formulation (IAWPS 95)
- Improved Calculation Speed
- Agreement with ITS-90 International Temperature Scale
- New High Temperature Region
- Properties of Metastable Steam

The entire set of equations of IAPWS-IF97, used by the application for calculation of thermodynamic properties, is defined by the following temperature and pressure range:

- 273.15 <= T <= 1073.15 K p <= 100 MPa
- 1073.15 K < T <= 2273.15 K p <= 50 MPa

Figure 1 shows the five regions into which the entire range of validity of IAPWS-IF97 is divided.

**Fig.1** Steam table **regions** defined in IAPWS-IF97

For more detailed information about the boundaries of the regions, and equations involved refer to *"Release on the IAPWS Industrial Formulation 1997 for the Thermodynamic Properties of Water* and Steam" presented by *The International Association for the Properties of Water and Steam*.

The entire set of equations of IAPWS-95, used by the application for calculation of thermodynamic properties, is defined by the following temperature and pressure range:

- Melting / Sublimation curve <= T <= 5000 K p <= 100000 MPa

The equation for surface tension between liquid and vapor phase has a range of validity from the triple point to the critical point:

- 273.16 <= T <= 647.096 K

The equations for dynamic and kinematic viscosity are valid in the range:

- 216.6 K <= T <= 1000 K 0 <= p <= 100 MPa
- 0 °C <= t <= 150 °C p <= 500 MPa
- 150 °C < t <= 600 °C p <= 350 MPa
- 600 °C < t <= 900 °C p <= 300 MPa.

The equations for thermal conductivity and thermal diffusivity are valid in the range:

- 216.6 K <= T <= 1000 K
- 0 °C <= t <= 500 °C p <= 100 MPa
- 500 °C < t <= 650 °C p <= 70 MPa
- 650 °C < t <= 800 °C p <= 40 MPa.

Prandtl number is dependent of dynamic viscosity and thermal conductivity, so it has range of validity according to these properties.

"Since the 5th International Conference on the Properties of Steam in London in 1956, the specific internal energy and the specific entropy of the saturated liquid at the triple point have been set equal to zero. Thus, at the triple-point temperature T = 273.16 K,"

- u
_{t}^{'}= 0- s
_{t}^{'}= 0

To calculate properties of water and steam using **IAPWS-IF97**, Steam97Web allows up to 16 different combinations of input variables in SI or English units:

- 1 f (pressure, temperature)
- 2 f (pressure, enthalpy)
- 3 f (pressure, entropy)
- 4 f (pressure, specific volume)
- 5 f (pressure, internal energy)
- 6 f (temperature, enthalpy)
- 7 f (temperature, entropy)
- 8 f (temperature, specific volume)
- 9 f (temperature, internal energy)
- 10f (enthalpy, entropy)
- 11f (internal energy, entropy)
- 12f (specific volume, entropy)
- 13f (enthalpy, specific volume)
- 14f (internal energy, specific volume)
- 15f (pressure, quality)
- 16f (temperature, quality)

Range of validity for listed functions:

- Functions 1-14 are valid in all five regions defined by the IAPWS-IF97
- Functions 15 and 16 are valid in the region 4 (saturation region) only

To calculate properties of water and steam using **IAPWS-95**, Steam97Web allows up to 11 different combinations of input variables in SI or English units:

- 1 f (pressure, temperature)
- 2 f (pressure, enthalpy)
- 3 f (pressure, entropy)
- 4 f (pressure, specific volume)
- 5 f (pressure, internal energy)
- 6 f (temperature, enthalpy)
- 7 f (temperature, entropy)
- 8 f (temperature, specific volume)
- 9 f (temperature, internal energy)
- 10f (pressure, quality)
- 11f (temperature, quality)

Range of validity for listed functions:

- Functions 10 and 11 are valid in the saturation region only

For input pressure, always enter absolute pressure and not gauge pressure.

The following 32 thermodynamic and transport properties can be calculated with Steam97Web:

- 1 Pressure,
**p** - 2 Temperature,
**t** - 3 Density,
**d** - 4 Specific volume,
**v** - 5 Specific enthalpy,
**h** - 6 Specific entropy,
**s** - 7 Specific exergy,
**ex** - 8 Specific internal energy,
**u** - 9 Specific isobaric heat capacity,
**cp** - 10Specific isochoric heat capacity,
**cv** - 11Speed of sound,
**w** - 12Isentropic exponent,
**kapa** - 13Specific Helmholtz free energy,
**H** - 14Specific Gibbs free energy,
**G** - 15Compressibility factor,
**Z** - 16Steam quality,
**x** - 17Region (
**IAPWS-IF97 only**),**region** - 18Isobaric volume expansion coefficient,
**alpha** - 19Isothermal compressibility,
**Kt** - 20Partial derivative (dV/dT)p,
**dvdt** - 21Partial derivative (dV/dP)T,
**dvdp** - 22Partial derivative (dP/dT)v,
**dpdt** - 23Partial derivative (dP/dV)T,
**dpdv** - 24Isothermal Joule-Thomson coefficient,
**iJTC** - 25Joule-Thomson coefficient,
**JTC** - 26Static dielectric constant (
**IAPWS-95 only**),**dc** - 27Dynamic viscosity,
**dv** - 28Kinematic viscosity,
**kv** - 29Thermal conductivity,
**tc** - 30Thermal diffusivity,
**td** - 31Prandtl number,
**Pr** - 32Surface tension,
**Sigma**

To open a new file, do the following:

- Choose
**File**,**Open**menu item

Alternatively, press the "**New**" toolbar button.

This will clear all currently displayed data on the forms.

To save calculated properties to your local computer, use the following steps:

- Choose
**File**,**Save to Excel as CSV**menu item. The File Download dialog appears - Alternatively, choose
**File**,**Save to Excel as CSV Unicode**menu item. The File Download dialog appears - Choose
**Save**to save the document to your computer

The CSV Unicode format will save properly some special characters contained in the definition of units. Since CSV is just a text file you can open a saved file with any text editor, for example Notepad.

On the "**Setup Pane**" in the "**Units**" group box, set units as required. SI and English units are available.

In the "Formulation" group box, on the "Setup Pane", set desired formulation to use, Industrial (IAPWS-IF97) and Scientific (IAPWS-95) are available.

On the "**Setup Pane**" In the "**Ambient**" group box, set a reference temperature of the environment. After entering a temperature press the "**Update**" button. The reference temperature will be used for the calculation of exergy.

At the top of the *Steam Table Calculator Page* there are two tabs, which enable you to select between "*General properties*" and "*Saturation properties*" of water and steam. On the first tab you can calculate water and steam properties in all regions, as defined by the application, including saturation properties. For example, if you enter input data that defines a point inside the saturation region, properties will be calculated and displayed in the same way as properties for all other regions. On the other hand, on the second tab you will be able to calculate water and steam properties only in the saturation region.

In order to calculate water and steam properties valid in all regions, select the first tab "*General properties*", and use the following steps:

**Choose units**, SI or English**Select**one of the 14 different functions based on available input variables**Enter**data for the first parameter**Enter**data for the second parameter- Press the "
**Calculate**" button to perform calculation

Detailed result of a calculation is displayed in the main table, located in the lower part of the input form, and also 17 main properties are displayed in the "Output Pane". Input arguments used in a calculation are displayed in red. The last column "IAPWS" displays the formulation used for performing the calculation.

**Fig.2** Calculation of general properties of water and steam

In order to calculate water and steam properties in the saturation region, select the second tab "*Saturation properties*", and use the following steps:

**Choose units**, SI or English**Select**one of the 15 different functions based on available input variables**Enter**data for the first parameter**Enter**data for the second parameter- Press the "
**Calculate**" button to perform calculation

Detailed result of calculation is displayed in the main table, located in the lower part of the input form, and also 17 main properties are displayed in the "Output Pane". Input arguments used for calculation are displayed in red. The last column "IAPWS" displays the formulation used for performing the calculation.

**Fig.3** Calculation of saturation properties of water and steam

In the Output Pane results are always inserted at the top, so you don't have to scroll to see the latest result.

To calculate steam consumption of a steam turbine, follow these steps:

- Select the "
**Steam Turbine**" tab - In the "Select Calculator" group box select "
**Turbine steam consumption calculator**" radio button - Enter required input data in the "
**Input Data**" group box - Press the "
**Calculate**" button

Results of the calculation will be displayed in the first empty "results" column in the main pane.

To calculate steam turbine efficiency, follow these steps:

- Select the "
**Steam Turbine**" tab - In the "Select Calculator" group box select "
**Turbine efficiency calculator**" radio button - Enter required input data in the "
**Input Data**" group box - Press the "
**Calculate**" button

Results of the calculation will be displayed in the first empty "results" column in the main pane.

To calculate steam turbine power, follow these steps:

- Select the "
**Steam Turbine**" tab - In the "Select Calculator" group box select "
**Turbine power calculator**" radio button - Enter required input data in the "
**Input Data**" group box - Press the "
**Calculate**" button

Results of the calculation will be displayed in the first empty "results" column in the main pane.

Before making the fourth calculation, press the "Clear results" button to clear results from the 3 available result columns in the main pane.

For each steam turbine calculation, calculated inlet and exhaust conditions of the turbine will be displayed in the "Output pane" as well. To distinguish turbine results from other data, these rows will be displayed in green.

To calculate flash evaporation of condensate at saturation, follow these steps:

- Select the "
**Flash Evaporation**" tab - In the "Condensate" group box select "
**Condensate at saturation**" radio button - Enter required input data in the "
**Input Data**" group box - Press the "
**Calculate**" button

Results of the calculation will be displayed in the first empty row in the main pane.

To calculate flash evaporation of subcooled condensate, follow these steps:

- Select the "
**Flash Evaporation**" tab - In the "Condensate" group box select "
**Subcooled condensate**" radio button - Enter required input data in the "
**Input Data**" group box - Press the "
**Calculate**" button

Results of the calculation will be displayed in the first empty row in the main pane.

For each flash evaporator calculation, calculated inlet and outlet conditions will be displayed in the "Output pane" as well. To distinguish flash evaporation results from other data, inlet properties will be displayed in blue and outlet properties in red.

To display point(s) on Steam Table Mollier diagrams use the following steps:

**Calculate**a few points you want to display- Click on the "
**Diagrams, Add / Edit Points**" menu item, the following dialog box should open **Select units**, to work with SI units select the SI Units Tab radio button" otherwise select English units radio button- In the "
**Displayed Point ID's**" edit box type ID's of the points you want to display from the ID's column in the Output Pane, for example to display the first 3 points type: 1,2,3 - In the "
**Displayed Point labels**" edit box type the labels (of your choice) of the respective points, for example: a,b,c - The number of points and the number of labels should
**match** - Press the "
**Save**" button and points will be displayed on all diagrams (Fig.5)

OPTIONAL - You may open "**Setup UI for Points**" dialog box (Fig.4), by choosing "**Diagrams, Setup UI for Points**" menu item and change default radius and color of the points. This UI setup will be applied to all displayed points.

**Fig.4** Add points to Steam Table Mollier diagrams

**Fig.5** Setup UI for points displayed on Steam Table diagrams

**Fig.6** Displayed points on T-S diagram for water and steam

Diagrams are available in SI and English units.

To edit point(s) already displayed on the diagrams use the following steps:

- Click on the "
**Diagrams, Add / Edit Points**" menu item to open "Add / Edit Points" dialog box - In the "
**Displayed Point ID's**" edit box make required changes - In the "
**Displayed Point Labels**" edit box make required changes - Press the "
**Save**" button and modified points will be displayed on all diagrams

To display line(s) or curve(s) on the diagrams use the following steps:

- Calculate and display a few points on the diagrams (see the
**Add Points**section) - Click on the "
**Diagrams, Add a Line or a Curve**" menu item to open "Add a Line or a Curve" dialog box - In the edit box "
**Add labels to define a new series**", add labels: a,b,c - In the edit box "
**Add name of the series**" type a name of a line/curve, for example: test - In the "
**Set type of series**" combo box select line or spline option. Spline is used to draw curves and you must provide at least 3 points to make it effective - Press the "
**Save**" button and lines and curves will be displayed on all diagrams (Fig.8)

OPTIONAL - You may open "**Setup UI for Lines and Curves**" dialog box (Fig.8), by choosing "**Diagrams, Setup UI for Lines and Curves**" menu item and change default width and color of the lines and curves. This UI setup will be applied to all displayed lines and curves.

**Fig.7** Add a line or a curve to Steam Mollier diagrams

Edit box "**Labels of currently displayed points**" will show you available points for the creation of line(s) and curve(s).

**Fig.8** Setup UI for lines and curves on Mollier diagrams for water and steam

**Fig.9** Simplified Rankine cycle displayed on steam tables T-S diagram

To edit a line or a curve already displayed on the Steam Table diagrams use the following steps:

- Click on the "
**Diagrams, Edit a Line or a Curve**" menu item to open "Edit a Line or a Curve" dialog box - In the combo box "
**Select a series to edit**" choose a line or a curve you want to modify **Make required changes**to the currently selected line or curve- Press the "
**Save**" button to close the dialog box

**Fig.10** Edit a line or a curve displayed on Steam Table Mollier diagrams

To save a diagram use the following steps:

**Click**the right mouse button on a diagram- On the context menu choose "
**Save Picture As...**" menu option

To print a diagram use the following steps:

**Resize**the diagram by resizing the browser window and / or close the Output and Setup panes**Click**the right mouse button on a diagram- On the context menu choose "
**Print Picture...**" menu option **Alternatively**, save a diagram to your desktop and print it from one of available image handling applications

The "**Gas Tables Calculator**" calculates caloric properties of moist air and undissociated combustion gases from 200 K up to 3300 K. It also provides a dissociation model which enables calculation of caloric properties of dissociated combustion gases at temperatures up to 2000 K, assuming complete combustion with λ > 1.05.

The model is based on the new set of equations for technical applications, called:

- "Thermodynamic Property Models for Moist air and Combustion Gases"

The formulation was developed by D. Bücker, R. Span and W. Wagner, and presented in the "Journal of Engineering for Gas Turbines and Power" (January 2003).

To calculate properties of combustion gases use the following steps:

- Select the "
**Gas Tables**" tab - In the "
**Gas Components**" group box enter values for each of the eight component in percent - Optionally check the "
**Include Dissociation**" check box, to include effects of dissociation - Press "
**Calculate**" button

Results of the calculation will be displayed in the first empty row in the main pane.

NOTE:

You must enter values for all eight gas components and their sum must be exactly 100 %. For components which are not present enter zero.