def test_less_expected(self, m):
check_dof(m, fail_flag=False, expected_dof=-1)
msg = r"Unexpected degrees of freedom: Degrees of freedom on unknown = 1. Expected -1. Fix 2 variable\(s\)"
with pytest.raises(ValueError, match=msg):
check_dof(m, fail_flag=True, expected_dof=-1)
with pytest.raises(ValueError, match=msg):
assert_degrees_of_freedom(m, -1)
def optimize_set_up(m, water_recovery=None):
for pump in m.fs.PrimaryPumps.values():
pump.control_volume.properties_out[0].pressure.unfix()
pump.control_volume.properties_out[0].pressure.setlb(10e5)
pump.control_volume.properties_out[0].pressure.setub(85e5)
pump.deltaP.setlb(0)
# unfix eq pumps
for pump in m.fs.BoosterPumps.values():
pump.control_volume.properties_out[0].pressure.unfix()
pump.control_volume.properties_out[0].pressure.setlb(10e5)
pump.control_volume.properties_out[0].pressure.setub(85e5)
pump.deltaP.setlb(0)
# unfix stages
for idx, stage in m.fs.ROUnits.items():
stage.area.unfix()
stage.width.unfix()
stage.area.setlb(1)
stage.area.setub(1000)
stage.width.setlb(0.1)
stage.width.setub(100)
stage.N_Re[0, 0].unfix()
if idx > m.fs.StageSet.first():
stage.B_comp.unfix()
stage.B_comp.setlb(3.5e-8)
stage.B_comp.setub(3.5e-8 * 1e3)
min_avg_flux = 1 # minimum average water flux [kg/m2-h]
min_avg_flux = (min_avg_flux / 3600 * pyunits.kg / pyunits.m**2 / pyunits.s
) # [kg/m2-s]
# additional constraints
if water_recovery is not None:
m.fs.water_recovery.fix(
water_recovery) # product mass flow rate fraction of feed [-]
# ---checking model---
assert_units_consistent(m)
assert_degrees_of_freedom(
m, 4 * m.fs.NumberOfStages - (1 if (water_recovery is None) else 2))
return m
def main():
m = build()
set_operating_conditions(m)
assert_degrees_of_freedom(m, 0)
initialize_system(m) # initialization needed for ozone unit
results = solve(m)
display_results(m)
add_costing(m)
initialize_costing(m)
assert_degrees_of_freedom(m, 0)
assert_units_consistent(m)
results = solve(m)
display_costing(m)
return m, results
def optimize_set_up(m):
# objective
m.fs.objective = Objective(expr=m.fs.costing.LCOW)
# unfix decision variables and add bounds
# pump 1 and pump 2
m.fs.P1.control_volume.properties_out[0].pressure.unfix()
m.fs.P1.control_volume.properties_out[0].pressure.setlb(10e5)
m.fs.P1.control_volume.properties_out[0].pressure.setub(80e5)
m.fs.P1.deltaP.setlb(0)
m.fs.P2.control_volume.properties_out[0].pressure.setlb(10e5)
m.fs.P2.control_volume.properties_out[0].pressure.setub(80e5)
m.fs.P2.deltaP.setlb(0)
# RO
m.fs.RO.area.setlb(1)
m.fs.RO.area.setub(150)
# additional specifications
m.fs.product_salinity = Param(
initialize=500e-6, mutable=True
) # product NaCl mass fraction [-]
m.fs.minimum_water_flux = Param(
initialize=1.0 / 3600.0, mutable=True
) # minimum water flux [kg/m2-s]
# additional constraints
m.fs.eq_product_quality = Constraint(
expr=m.fs.product.properties[0].mass_frac_phase_comp["Liq", "NaCl"]
<= m.fs.product_salinity
)
iscale.constraint_scaling_transform(
m.fs.eq_product_quality, 1e3
) # scaling constraint
m.fs.eq_minimum_water_flux = Constraint(
expr=m.fs.RO.flux_mass_phase_comp[0, 1, "Liq", "H2O"] >= m.fs.minimum_water_flux
)
# ---checking model---
assert_degrees_of_freedom(m, 1)
def main():
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)
display_results(m)
add_costing(m)
initialize_costing(m)
assert_degrees_of_freedom(m, 0)
assert_units_consistent(m)
results = solve(m)
display_costing(m)
return m, results
def main(erd_type="pressure_exchanger"):
m = build(erd_type=erd_type)
set_operating_conditions(m)
assert_degrees_of_freedom(m, 0)
initialize_system(m)
assert_degrees_of_freedom(m, 0)
solve(m)
display_results(m)
add_costing(m)
initialize_costing(m)
assert_degrees_of_freedom(m, 0)
solve(m, tee=True)
display_costing(m)
return m
def check_dof(blk, dof_expected=0):
assert_degrees_of_freedom(blk, dof_expected)
def test_expected(self, m):
check_dof(m, fail_flag=False, expected_dof=1)
check_dof(m, fail_flag=True, expected_dof=1)
assert_degrees_of_freedom(m, 1)
def test_build(self, system_frame):
m = system_frame
assert_degrees_of_freedom(m, 20)
assert_units_consistent(m)
