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How to add a flowsheet to UI

Add a Flowsheet to the UI

This API is intended for model developers who would like to connect their flowsheets to the UI. Developers can select which variables to "export" to the UI for each component of the model, and provide extra metadata (display name, description) for them. For flowsheets, they should also specify how to build and solve the flowsheets.

For reference, see FlowsheetInterface and FlowsheetExport in the watertap.ui.fsapi module.

Define the export_to_ui function​

In some Python module, define the function export_to_ui, which will look similar to this:

from idaes_flowsheet_processor.api import FlowsheetInterface, FlowsheetCategory

def export_to_ui():
    return FlowsheetInterface(
        name="NF-DSPM-DE",
        do_export=export_variables,
        do_build=build_flowsheet,
        do_solve=solve_flowsheet,
        get_diagram=get_diagram,
        requires_idaes_solver=True,
        category=FlowsheetCategory.wastewater,
        build_options={
            "Bypass": {
                "name": "bypass option",
                "display_name": "With Bypass",
                "values_allowed": ['false', 'true'],
                "value": "false"
            }
        }
    )

Required Functions​

do_export​

This function defines the variables that will be displayed on the UI.

There are two ways to export the variables:

Using the Python API​

def export_variables(flowsheet=None, exports=None, build_options=None, **kwargs):
    fs = flowsheet
    exports.add(
        obj=fs.feed.properties[0].flow_vol_phase["Liq"],
        name="Volumetric flow rate",
        ui_units=pyunits.L / pyunits.hr,
        display_units="L/h",
        rounding=2,
        description="Inlet volumetric flow rate",
        is_input=True,
        input_category="Feed",
        is_output=False,
        output_category="Feed",
    )
    exports.add(
        obj=fs.NF.pump.outlet.pressure[0],
        name="NF pump pressure",
        ui_units=pyunits.bar,
        display_units="bar",
        rounding=2,
        description="NF pump pressure",
        is_input=True,
        input_category="NF design",
        is_output=True,
        output_category="NF design",
    )

Using a CSV file​

def export_variables(flowsheet=None, exports=None, build_options=None, **kwargs):
    exports.from_csv(file="nf_exports.csv", flowsheet=flowsheet)

Example CSV format:

"obj", "name", "descriptions", "ui_units", "display_units", "rounding", "is_input", "input_category", "is_output", "output_category"
"fs.feed.properties[0].flow_vol_phase['Liq']","Volumetric flow rate","Volumetric flow rate","units.L / units.hr","L/h",2,true,"Feed",false,""
"fs.NF.pump.outlet.pressure[0]","NF pump pressure","Nanofiltration pump outlet pressure","units.bar","bar",true,"NF design",true,"NF design"
"fs.NF.product.properties[0].flow_vol_phase['Liq']","NF product volume flow rate","Nanofiltration product volume flow rate","units.L / units.hr","L/h",2,false,"",true,"NF design"

do_build​

This function defines the build function for a flowsheet.

from watertap.examples.flowsheets.case_studies.wastewater_resource_recovery.metab.metab import (
    build,
    set_operating_conditions,
    initialize_system,
    solve,
    add_costing,
    adjust_default_parameters,
)

def build_flowsheet():
    m = build()
    set_operating_conditions(m)
    assert_degrees_of_freedom(m, 0)
    assert_units_consistent(m)
    initialize_system(m)
    results = solve(m)
    assert_optimal_termination(results)
    add_costing(m)
    assert_degrees_of_freedom(m, 0)
    m.fs.costing.initialize()
    adjust_default_parameters(m)
    results = solve(m)
    assert_optimal_termination(results)
    return m

do_solve​

This function defines the solve function for a flowsheet.

from watertap.examples.flowsheets.case_studies.wastewater_resource_recovery.metab.metab import solve

def solve_flowsheet(flowsheet=None):
    fs = flowsheet
    results = solve(fs)
    return results

Additional Options​

Build function using build options​

def build_flowsheet(build_options=None, **kwargs):
    if build_options is not None:
        if build_options["Bypass"].value == "true":
            solver = get_solver()
            m = nf_with_bypass.build()
            nf_with_bypass.initialize(m, solver)
            nf_with_bypass.unfix_opt_vars(m)
        else:
            solver = get_solver()
            m = nf.build()
            nf.initialize(m, solver)
            nf.add_objective(m)
            nf.unfix_opt_vars(m)
    else:
        solver = get_solver()
        m = nf.build()
        nf.initialize(m, solver)
        nf.add_objective(m)
        nf.unfix_opt_vars(m)
    return m

Custom diagram function​

def get_diagram(build_options):
    if build_options["Bypass"].value == "true":
        return "nf_with_bypass_ui.png"
    else:
        return "nf_ui.png"

Enabling UI to Discover Flowsheet​

To allow the UI to discover a flowsheet, define an entry point in setup.py with the path to the export file:

entry_points={
    "watertap.flowsheets": [
        "nf = watertap.examples.flowsheets.nf_dspmde.nf_ui",
        "metab = watertap.examples.flowsheets.case_studies.wastewater_resource_recovery.metab.metab_ui",
    ]
}

For a complete overview of all arguments, see FlowsheetInterface.