Energy Metering blocks

Steam Properties (STM) function block

The STM function block calculates steam enthalpy, entropy, and specific volume for a given gauge pressure and a given temperature. The block calculations apply to water in the IF97 region. The valid ranges are:
  • Temperature: 32 to 3632°F (0 to 2000°C)
  • Pressure:
    • P > -14.696 psig (0 Mpa )

    • P <= 14489 psig (100 Mpa)

      for temperature < 1472°F (800°C)

      or

      P <= 7237.1 psig (50 Mpa )

      for temperature => 1472°F (800°C)

The minimum valid temperature for saturated steam is the higher of 383°F (195°C) or the saturation temperature for the input pressure.

Figure: Steam Properties function block

The block calculations are based on The International Association for the Properties of Water and Steam (IAPWS) Revised Release on the IAPWS Industrial Formulation 1997 for the Thermodynamic Properties of Water and Steam.

Note

If the input values are out of the specified IF97 range, the values used for calculation are limited to the IF97 boundary values and the block status is set to Bad.

The following figure shows the internal components of the STM function block.

STM function block schematic diagram

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