COCO - CAPE-OPEN to CAPE-OPEN simulation environment


The 'Water' stand-alone property package that is installed with COCO is based on the IAPWS-97 industrial specification for properties of water and steam. It is useful for simulating utility steam. This can for example be done by adding the Water Property Package to your simulation in addition to the property package that is used for calculation of the chemistry. A separate stream type can be used in COFE for utility steam. This stream type can then be used to simulate the steam side of a heat exchange, or the water side of a cooler.

The Water Property Package implements a CAPE-OPEN version 1.1 stand-alone thermodynamic property package.

The Water Property Package exposes compound constants: critical density, critical pressure, critical temperature, critical volume, molecular weight, triple point pressure, triple point temperature, CAS registry number, chemical formula, IUPAC name and normal boiling point. The only compound exposed by this property package is water.

The Water Property Package exposes temperature dependent properties: surface tension of saturated liquid, thermal conductivity of liquid and vapor at the saturation line, vapor pressure, volume change upon vaporization, volumes of liquid and vapor at the saturation line, viscosity of liquid and vapor at the saturation line, ideal gas enthalpy and ideal gas entropy. The latter two properties are not captured by the IAPWS-97 standard, and are present in order to allow reference state calculations for the ideal gas state only. The ideal gas enthalpy is given as the enthalpy of the vapor phase at zero pressure. The ideal gas entropy is given as the integral from reference temperature to T of CP,ideal/T, plus the vapor enthalpy at internal reference conditions. The ideal gas heat capacity CP,ideal for this purpose comes from an external correlation.

The Water Property Package exposes the following non-constant properties: density, enthalpy, entropy, Gibbs energy, heat capacities CP and CV, internal energy, molecular weight, thermal conductivity, volume and viscosity.

The above properties are based on:

The IAPWS-97 formulation splits the thermodynamic calculations up into regions as shown in the figure below. This figure therefore also shows the valid regions for calculation with the Water package:

IAPWS regions

The water package provides equilibrium calculation based on the following combination of specification variables: