Contrec 515 – SC01

Frequency Input Steam Computer

The 515 SC01 application measures the volume, mass and energy content of steam by using frequency volume flow input in conjunction with analog temperature and/or pressure input.

A selection of various modes makes it suitable for many steam applications. The instrument is compatible with a wide range of flowmeter frequency outputs. Millivolt signals, reed switches, Namur proximity switches or pulse trains can be selected via its smart front-panel programming.

The instrument calculates the mass flow and energy according to the IAPWS Industrial Formulation (1997) for the thermodynamic properties of steam. The equations use the pressure and temperature values to determine the specific volume and the specific enthalpy.

CALCULATIONS

The steam energy calculations are based on the IAPWS Industrial Formulation (1997).

Superheated steam regions are:

0°C < t < 800°C P < 100MPa
32°F < t < 1472°F P < 14500psia

800°C < t < 2000°C P < 10MPa
1472°F < t < 3632°F P < 1450psia

Saturated steam regions are:

0°C < t < 374°C (critical temperature)
32°F < t < 705°F

P < 22MPa (critical pressure)
P < 3190psia

Water region is:

0°C < t < t saturation at system pressure
32°C < t < t saturation at system pressure

Formulas

Mass flow = Volume flow/Specific volume

Energy flow = Mass flow x Specific enthalpy