def test_compressor():
m = pyo.ConcreteModel()
m.fs = idaes.core.FlowsheetBlock(default={"dynamic": False})
m.fs.properties = iapws95.Iapws95ParameterBlock()
m.fs.unit1 = cmodels.Compressor(default={"property_package": m.fs.properties})
m.fs.unit2 = hmodels.HelmIsentropicCompressor(default={"property_package": m.fs.properties})
# set inputs
Fin = 1000 # mol/s
Tin = 500 # K
Pin = 2222782.4 # Pa
Pout = 2.7*Pin # Pa
hin = pyo.value(iapws95.htpx(Tin*pyo.units.K, Pin*pyo.units.Pa)) # J/mol
eff = 0.324
m.fs.unit1.inlet.flow_mol[0].fix(Fin)
m.fs.unit2.inlet.flow_mol[0].fix(Fin)
m.fs.unit1.inlet.enth_mol[0].fix(hin)
m.fs.unit2.inlet.enth_mol[0].fix(hin)
m.fs.unit1.inlet.pressure[0].fix(Pin)
m.fs.unit2.inlet.pressure[0].fix(Pin)
m.fs.unit1.outlet.pressure[0].fix(Pout)
m.fs.unit2.outlet.pressure[0].fix(Pout)
m.fs.unit1.efficiency_isentropic.fix(eff)
m.fs.unit2.efficiency_isentropic.fix(eff)
m.fs.unit1.initialize()
m.fs.unit2.initialize()
assert pyo.value(m.fs.unit1.control_volume.properties_out[0].temperature) == \
pytest.approx(
pyo.value(m.fs.unit2.control_volume.properties_out[0].temperature),
rel=1e-7
)
assert pyo.value(m.fs.unit1.control_volume.work[0]) == pytest.approx(
pyo.value(m.fs.unit2.control_volume.work[0]), rel=1e-7)
def test_compressor_pump_compare():
m = pyo.ConcreteModel()
m.fs = idaes.core.FlowsheetBlock(default={"dynamic": False})
m.fs.properties = iapws95.Iapws95ParameterBlock()
m.fs.unit1 = hmodels.HelmPump(
default={"property_package": m.fs.properties})
m.fs.unit2 = hmodels.HelmIsentropicCompressor(
default={"property_package": m.fs.properties})
Fin = 1e4 # mol/s
hin = 4000 # J/mol
Pin = 101325 # Pa
Pout = 2 * Pin # Pa
eff = 0.7
m.fs.unit1.inlet.flow_mol[0].fix(Fin)
m.fs.unit1.inlet.enth_mol[0].fix(hin)
m.fs.unit1.inlet.pressure[0].fix(Pin)
m.fs.unit1.outlet.pressure[0].fix(Pout)
m.fs.unit1.efficiency_pump.fix(eff)
m.fs.unit2.inlet.flow_mol[0].fix(Fin)
m.fs.unit2.inlet.enth_mol[0].fix(hin)
m.fs.unit2.inlet.pressure[0].fix(Pin)
m.fs.unit2.outlet.pressure[0].fix(Pout)
m.fs.unit2.efficiency_isentropic.fix(eff)
m.fs.unit1.initialize()
m.fs.unit2.initialize()
# The pump calculations are a bit more approximate assuming incompressible
# fluid entropy is independent of pressure, so the results here should be
# close, but not exactly the same.
assert pyo.value(m.fs.unit1.control_volume.properties_out[0].temperature) == \
pytest.approx(
pyo.value(m.fs.unit2.control_volume.properties_out[0].temperature),
rel=1e-3
)
assert pyo.value(m.fs.unit1.control_volume.work[0]) == pytest.approx(
pyo.value(m.fs.unit2.control_volume.work[0]), rel=1e-3)