Source code for tespy.components.nodes.drum

# -*- coding: utf-8

"""Module of class Drum.


This file is part of project TESPy (github.com/oemof/tespy). It's copyrighted
by the contributors recorded in the version control history of the file,
available from its original location tespy/components/nodes/drum.py

SPDX-License-Identifier: MIT
"""

import numpy as np

from tespy.components.nodes.droplet_separator import DropletSeparator
from tespy.tools.fluid_properties import h_mix_pQ


[docs]class Drum(DropletSeparator): r""" A drum separates saturated gas from saturated liquid. **Mandatory Equations** - :py:meth:`tespy.components.nodes.base.NodeBase.mass_flow_func` - :py:meth:`tespy.components.nodes.base.NodeBase.pressure_equality_func` - :py:meth:`tespy.components.nodes.droplet_separator.DropletSeparator.fluid_func` - :py:meth:`tespy.components.nodes.droplet_separator.DropletSeparator.energy_balance_func` - :py:meth:`tespy.components.nodes.droplet_separator.DropletSeparator.outlet_states_func` Inlets/Outlets - in1, in2 (index 1: from economiser, index 2: from evaporator) - out1, out2 (index 1: saturated liquid, index 2: saturated gas) Image .. image:: /api/_images/Drum.svg :alt: flowsheet of the drum :align: center :class: only-light .. image:: /api/_images/Drum_darkmode.svg :alt: flowsheet of the drum :align: center :class: only-dark Parameters ---------- label : str The label of the component. design : list List containing design parameters (stated as String). offdesign : list List containing offdesign parameters (stated as String). design_path : str Path to the components design case. local_offdesign : boolean Treat this component in offdesign mode in a design calculation. local_design : boolean Treat this component in design mode in an offdesign calculation. char_warnings : boolean Ignore warnings on default characteristics usage for this component. printout : boolean Include this component in the network's results printout. Note ---- If you are using a drum in a network with multiple fluids, it is likely the fluid propagation causes trouble. If this is the case, try to specify the fluid composition at another connection of your network. This component assumes, that the fluid composition between outlet 1 and inlet 2 does not change, thus there is no equation for the fluid mass fraction at the inlet 2! Example ------- The drum separates saturated gas from saturated liquid. The liquid phase is transported to an evaporator, the staturated gas phase is extracted from the drum. In this example ammonia is evaporated using ambient air. A characteristic function is applied for the heat transfer coefficient of the evaporator. It is possible to load the CharLine with the function :code:`load_default_char` from the default lines. We want to use the 'EVAPORATING FLUID' lines of the heat exchanger. >>> from tespy.components import Sink, Source, Drum, Pump, HeatExchanger >>> from tespy.connections import Connection, Ref >>> from tespy.networks import Network >>> from tespy.tools.characteristics import CharLine >>> from tespy.tools.characteristics import load_default_char as ldc >>> import shutil >>> import numpy as np >>> nw = Network(fluids=['NH3', 'air'], T_unit='C', p_unit='bar', ... h_unit='kJ / kg', iterinfo=False) >>> fa = Source('feed ammonia') >>> amb_in = Source('air inlet') >>> amb_out = Sink('air outlet') >>> s = Sink('steam') >>> dr = Drum('drum') >>> dr.component() 'drum' >>> ev = HeatExchanger('evaporator') >>> erp = Pump('evaporator reciculation pump') >>> f_dr = Connection(fa, 'out1', dr, 'in1') >>> dr_erp = Connection(dr, 'out1', erp, 'in1') >>> erp_ev = Connection(erp, 'out1', ev, 'in2') >>> ev_dr = Connection(ev, 'out2', dr, 'in2') >>> dr_s = Connection(dr, 'out2', s, 'in1') >>> nw.add_conns(f_dr, dr_erp, erp_ev, ev_dr, dr_s) >>> amb_ev = Connection(amb_in, 'out1', ev, 'in1') >>> ev_amb = Connection(ev, 'out1', amb_out, 'in1') >>> nw.add_conns(amb_ev, ev_amb) The ambient air enters the evaporator at 30 °C. The pinch point temperature difference (ttd_l) of the evaporator is at 5 K, and 1 MW of heat should be transferred. State of ammonia at the inlet is at -5 °C and 5 bar. From this design it is possible to calculate offdesign performance at 75 % part load. >>> char1 = ldc('heat exchanger', 'kA_char1', 'DEFAULT', ... CharLine) >>> char2 = ldc('heat exchanger', 'kA_char2', 'EVAPORATING FLUID', ... CharLine) >>> ev.set_attr(pr1=0.999, pr2=0.99, ttd_l=5, kA_char1=char1, ... kA_char2=char2, design=['pr1', 'ttd_l'], ... offdesign=['zeta1', 'kA_char']) >>> ev.set_attr(Q=-1e6) >>> erp.set_attr(eta_s=0.8) >>> f_dr.set_attr(p=5, T=-5) >>> erp_ev.set_attr(m=Ref(f_dr, 4, 0), fluid={'air': 0, 'NH3': 1}) >>> amb_ev.set_attr(fluid={'air': 1, 'NH3': 0}, T=30) >>> ev_amb.set_attr(p=1) >>> nw.solve('design') >>> nw.save('tmp') >>> round(ev_amb.T.val - erp_ev.T.val ,1) 5.0 >>> round(f_dr.h.val, 1) 322.7 >>> round(dr_erp.h.val, 1) 364.9 >>> round(ev_dr.h.val, 1) 687.2 >>> round(f_dr.m.val, 2) 0.78 >>> ev.set_attr(Q=-0.75e6) >>> nw.solve('offdesign', design_path='tmp') >>> round(f_dr.m.val, 2) 0.58 >>> round(ev_amb.T.val - erp_ev.T.val ,1) 3.0 >>> shutil.rmtree('./tmp', ignore_errors=True) """
[docs] @staticmethod def component(): return 'drum'
[docs] @staticmethod def inlets(): return ['in1', 'in2']
[docs] @staticmethod def outlets(): return ['out1', 'out2']
[docs] @staticmethod def initialise_source(c, key): r""" Return a starting value for pressure and enthalpy at outlet. Parameters ---------- c : tespy.connections.connection.Connection Connection to perform initialisation on. key : str Fluid property to retrieve. Returns ------- val : float Starting value for pressure/enthalpy in SI units. .. math:: val = \begin{cases} 10^6 & \text{key = 'p'}\\ h\left(p, x=0 \right) & \text{key = 'h' at outlet 1}\\ h\left(p, x=1 \right) & \text{key = 'h' at outlet 2} \end{cases} """ if key == 'p': return 10e5 elif key == 'h': if c.source_id == 'out1': return h_mix_pQ(c.get_flow(), 0) else: return h_mix_pQ(c.get_flow(), 1)
[docs] @staticmethod def initialise_target(c, key): r""" Return a starting value for pressure and enthalpy at inlet. Parameters ---------- c : tespy.connections.connection.Connection Connection to perform initialisation on. key : str Fluid property to retrieve. Returns ------- val : float Starting value for pressure/enthalpy in SI units. .. math:: val = \begin{cases} 10^6 & \text{key = 'p'}\\ h\left(p, x=0 \right) & \text{key = 'h' at inlet 1}\\ h\left(p, x=0.7 \right) & \text{key = 'h' at inlet 2} \end{cases} """ if key == 'p': return 10e5 elif key == 'h': if c.target_id == 'in1': return h_mix_pQ(c.get_flow(), 0) else: return h_mix_pQ(c.get_flow(), 0.7)
[docs] def propagate_fluid_to_target(self, inconn, start): r""" Propagate the fluids towards connection's target in recursion. Parameters ---------- inconn : tespy.connections.connection.Connection Connection to initialise. start : tespy.components.component.Component This component is the fluid propagation starting point. The starting component is saved to prevent infinite looping. """ if self != start: start = self for outconn in self.outl: for fluid, x in inconn.fluid.val.items(): if (outconn.fluid.val_set[fluid] is False and outconn.good_starting_values is False): outconn.fluid.val[fluid] = x outconn.target.propagate_fluid_to_target(outconn, start)
[docs] def propagate_fluid_to_source(self, outconn, start): r""" Propagate the fluids towards connection's source in recursion. Parameters ---------- outconn : tespy.connections.connection.Connection Connection to initialise. start : tespy.components.component.Component This component is the fluid propagation starting point. The starting component is saved to prevent infinite looping. """ if self != start: start = self for inconn in self.inl: for fluid, x in outconn.fluid.val.items(): if (inconn.fluid.val_set[fluid] is False and inconn.good_starting_values is False): inconn.fluid.val[fluid] = x inconn.source.propagate_fluid_to_source(inconn, start)
[docs] def exergy_balance(self, T0): r""" Calculate exergy balance of a merge. Parameters ---------- T0 : float Ambient temperature T0 / K. Note ---- Please note, that the exergy balance accounts for physical exergy only. .. math:: \dot{E}_\mathrm{P} = \sum \dot{E}_{\mathrm{out,}j}^\mathrm{PH}\\ \dot{E}_\mathrm{F} = \sum \dot{E}_{\mathrm{in,}i}^\mathrm{PH} """ self.E_P = self.outl[0].Ex_physical + self.outl[1].Ex_physical self.E_F = self.inl[0].Ex_physical + self.inl[1].Ex_physical self.E_bus = np.nan self.E_D = self.E_F - self.E_P self.epsilon = self.E_P / self.E_F
[docs] def get_plotting_data(self): """ Generate a dictionary containing FluProDia plotting information. Returns ------- data : dict A nested dictionary containing the keywords required by the :code:`calc_individual_isoline` method of the :code:`FluidPropertyDiagram` class. First level keys are the connection index ('in1' -> 'out1', therefore :code:`1` etc.). """ return { 1: { 'isoline_property': 'p', 'isoline_value': self.outl[0].p.val, 'isoline_value_end': self.outl[1].p.val, 'starting_point_property': 'v', 'starting_point_value': self.outl[0].vol.val, 'ending_point_property': 'v', 'ending_point_value': self.outl[1].vol.val }}