Source code for tespy.connections.connection

# -*- coding: utf-8
"""Module of class Connection and class Ref.


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/connections/connection.py

SPDX-License-Identifier: MIT
"""

import numpy as np

from tespy.components.component import Component
from tespy.tools import fluid_properties as fp
from tespy.tools import logger
from tespy.tools.data_containers import DataContainer as dc
from tespy.tools.data_containers import FluidComposition as dc_flu
from tespy.tools.data_containers import FluidProperties as dc_prop
from tespy.tools.data_containers import ReferencedFluidProperties as dc_ref
from tespy.tools.data_containers import SimpleDataContainer as dc_simple
from tespy.tools.fluid_properties import CoolPropWrapper
from tespy.tools.fluid_properties import Q_mix_ph
from tespy.tools.fluid_properties import T_mix_ph
from tespy.tools.fluid_properties import T_sat_p
from tespy.tools.fluid_properties import dh_mix_dpQ
from tespy.tools.fluid_properties import dT_mix_dph
from tespy.tools.fluid_properties import dT_mix_pdh
from tespy.tools.fluid_properties import dT_sat_dp
from tespy.tools.fluid_properties import dv_mix_dph
from tespy.tools.fluid_properties import dv_mix_pdh
from tespy.tools.fluid_properties import h_mix_pQ
from tespy.tools.fluid_properties import h_mix_pT
from tespy.tools.fluid_properties import s_mix_ph
from tespy.tools.fluid_properties import v_mix_ph
from tespy.tools.fluid_properties import viscosity_mix_ph
from tespy.tools.fluid_properties.functions import dT_mix_ph_dfluid
from tespy.tools.fluid_properties.functions import p_sat_T
from tespy.tools.fluid_properties.helpers import get_mixture_temperature_range
from tespy.tools.fluid_properties.helpers import get_number_of_fluids
from tespy.tools.global_vars import ERR
from tespy.tools.global_vars import fluid_property_data as fpd
from tespy.tools.helpers import TESPyConnectionError
from tespy.tools.helpers import TESPyNetworkError
from tespy.tools.helpers import convert_from_SI


[docs] class Connection: r""" Class connection is the container for fluid properties between components. Parameters ---------- m : float, tespy.connections.connection.Ref Mass flow specification. m0 : float Starting value specification for mass flow. p : float, tespy.connections.connection.Ref Pressure specification. p0 : float Starting value specification for pressure. h : float, tespy.connections.connection.Ref Enthalpy specification. h0 : float Starting value specification for enthalpy. fluid : dict Fluid compostition specification. fluid0 : dict Starting value specification for fluid compostition. fluid_balance : boolean Fluid balance equation specification. x : float Gas phase mass fraction specification. T : float, tespy.connections.connection.Ref Temperature specification. Td_bp : float Temperature difference to boiling point at pressure corresponding pressure of this connection in K. v : float Volumetric flow specification. state : str State of the pure fluid on this connection: liquid ('l') or gaseous ('g'). design : list List containing design parameters (stated as string). offdesign : list List containing offdesign parameters (stated as string). design_path : str Path to individual design case for this connection. local_offdesign : boolean Treat this connection in offdesign mode in a design calculation. local_design : boolean Treat this connection in design mode in an offdesign calculation. printout : boolean Include this connection in the network's results printout. label : str Label of the connection. The default value is: :code:`'source:source_id_target:target_id'`. Note ---- - The fluid balance parameter applies a balancing of the fluid vector on the specified conntion to 100 %. For example, you have four fluid components (a, b, c and d) in your vector, you set two of them (a and b) and want the other two (components c and d) to be a result of your calculation. If you set this parameter to True, the equation (0 = 1 - a - b - c - d) will be applied. - The specification of values for design and/or offdesign is used for automatic switch from design to offdesign calculation: All parameters given in 'design', e.g. :code:`design=['T', 'p']`, are unset in any offdesign calculation, parameters given in 'offdesign' are set for offdesign calculation. Example ------- This example shows how to create connections and specify parameters. First create the required components and connect them in the next step. After that, it is possible specify parameters with the :code:`set_attr` method. >>> from tespy.components import Sink, Source >>> from tespy.connections import Connection, Ref >>> import numpy as np >>> so1 = Source('source1') >>> so2 = Source('source2') >>> si1 = Sink('sink1') >>> si2 = Sink('sink2') >>> so_si1 = Connection(so1, 'out1', si1, 'in1', label='connection 1') >>> so_si2 = Connection(so2, 'out1', si2, 'in1') >>> so_si1.label 'connection 1' >>> so_si2.label 'source2:out1_sink2:in1' There are different ways of setting parameters on connections: Specify - a numeric value (for attributes mass flow, pressure and enthalpy) - a numeric starting value (for attributes mass flow, pressure and enthalpy) - a dictionary (for attributes fluid and fluid0) - a boolean value (for attributes fluid_balance, local_design, local_offdesign). - a referenced value (mass flow, pressure, temperature, enthalpy). - numpy.nan or None (unsetting a value). - a string (for attributes design_path and state). - a list (for attributes design and offdesign). >>> so_si1.set_attr(v=0.012, m0=10, p=5, h=400, fluid={'H2O': 1}) >>> so_si2.set_attr(m=Ref(so_si1, 2, -5), h0=700, T=200, ... fluid={'N2': 1}, fluid_balance=True, ... design=['T'], offdesign=['m', 'v']) The set_attr method automatically converts your input in data_container information. >>> type(so_si1.v) <class 'tespy.tools.data_containers.FluidProperties'> >>> type(so_si1.fluid) <class 'tespy.tools.data_containers.FluidComposition'> If you want get a spcific value use the logic: connection.property.*. Aditionally, it is possible to use the :code:`get_attr` method. >>> so_si1.m.val0 10 >>> so_si1.m.is_set False >>> so_si1.m.get_attr('is_set') False >>> type(so_si2.m_ref.ref) <class 'tespy.connections.connection.Ref'> >>> so_si2.fluid_balance.is_set True >>> so_si2.m_ref.ref.get_attr('delta') -5 >>> so_si2.m_ref.is_set True >>> type(so_si2.m_ref.ref.get_attr('obj')) <class 'tespy.connections.connection.Connection'> Unset the specified temperature and specify temperature difference to boiling point instead. >>> so_si2.T.is_set True >>> so_si2.set_attr(Td_bp=5, T=None) >>> so_si2.T.is_set False >>> so_si2.Td_bp.val 5 >>> so_si2.set_attr(Td_bp=None) >>> so_si2.Td_bp.is_set False Specify the state keyword: The fluid will be forced to liquid or gaseous state in this case. >>> so_si2.set_attr(state='l') >>> so_si2.state.is_set True >>> so_si2.set_attr(state=None) >>> so_si2.state.is_set False >>> so_si2.set_attr(state='g') >>> so_si2.state.is_set True >>> so_si2.set_attr(state=None) >>> so_si2.state.is_set False """ def __init__(self, source, outlet_id, target, inlet_id, label=None, **kwargs): self._check_types(source, target) self._check_self_connect(source, target) self._check_connector_id(source, outlet_id, source.outlets()) self._check_connector_id(target, inlet_id, target.inlets()) self.label = f"{source.label}:{outlet_id}_{target.label}:{inlet_id}" if label is not None: self.label = label if not isinstance(label, str): msg = "Please provide the label as string." logger.error(msg) raise TypeError(msg) # set specified values self.source = source self.source_id = outlet_id self.target = target self.target_id = inlet_id # defaults self.new_design = True self.design_path = None self.design = [] self.offdesign = [] self.local_design = False self.local_offdesign = False self.printout = True # set default values for kwargs self.property_data = self.get_parameters() self.parameters = { k: v for k, v in self.get_parameters().items() if hasattr(v, "func") and v.func is not None } self.state = dc_simple() self.property_data0 = [x + '0' for x in self.property_data.keys()] self.__dict__.update(self.property_data) self.mixing_rule = None msg = ( f"Created connection from {self.source.label} ({self.source_id}) " f"to {self.target.label} ({self.target_id})." ) logger.debug(msg) self.set_attr(**kwargs) def _check_types(self, source, target): # check input parameters if not (isinstance(source, Component) and isinstance(target, Component)): msg = ( "Error creating connection. Check if source and target are " "tespy.components." ) logger.error(msg) raise TypeError(msg) def _check_self_connect(self, source, target): if source == target: msg = ( "Error creating connection. Cannot connect component " f"{source.label} to itself." ) logger.error(msg) raise TESPyConnectionError(msg) def _check_connector_id(self, component, connector_id, connecter_locations): if connector_id not in connecter_locations: msg = ( "Error creating connection. Specified connector for " f"{component.label} ({connector_id}) is not available. Choose " f"from " + ", ".join(connecter_locations) + "." ) logger.error(msg) raise ValueError(msg)
[docs] def set_attr(self, **kwargs): r""" Set, reset or unset attributes of a connection. Parameters ---------- m : float, tespy.connections.connection.Ref Mass flow specification. m0 : float Starting value specification for mass flow. p : float, tespy.connections.connection.Ref Pressure specification. p0 : float Starting value specification for pressure. h : float, tespy.connections.connection.Ref Enthalpy specification. h0 : float Starting value specification for enthalpy. fluid : dict Fluid composition specification. fluid0 : dict Starting value specification for fluid composition. fluid_balance : boolean Fluid balance equation specification. x : float Gas phase mass fraction specification. T : float, tespy.connections.connection.Ref Temperature specification. Td_bp : float Temperature difference to boiling point at pressure corresponding pressure of this connection in K. v : float Volumetric flow specification. state : str State of the pure fluid on this connection: liquid ('l') or gaseous ('g'). design : list List containing design parameters (stated as string). offdesign : list List containing offdesign parameters (stated as string). design_path : str Path to individual design case for this connection. local_offdesign : boolean Treat this connection in offdesign mode in a design calculation. local_design : boolean Treat this connection in design mode in an offdesign calculation. printout : boolean Include this connection in the network's results printout. Note ---- - The fluid balance parameter applies a balancing of the fluid vector on the specified connection to 100 %. For example, you have four fluid components (a, b, c and d) in your vector, you set two of them (a and b) and want the other two (components c and d) to be a result of your calculation. If you set this parameter to True, the equation (0 = 1 - a - b - c - d) will be applied. - The specification of values for design and/or offdesign is used for automatic switch from design to offdesign calculation: All parameters given in 'design', e.g. :code:`design=['T', 'p']`, are unset in any offdesign calculation, parameters given in 'offdesign' are set for offdesign calculation. - The property state is applied on pure fluids only. If you specify the desired state of the fluid at a connection the convergence check will adjust the enthalpy values of that connection for the first iterations in order to meet the state requirement. """ # set specified values for key in kwargs: if key == 'label': msg = 'Label can only be specified on instance creation.' logger.error(msg) raise TESPyConnectionError(msg) elif 'fluid' in key: self._fluid_specification(key, kwargs[key]) elif key in self.property_data or key in self.property_data0: self._parameter_specification(key, kwargs[key]) elif key == 'state': if kwargs[key] in ['l', 'g']: self.state.set_attr(val=kwargs[key], is_set=True) elif kwargs[key] is None: self.state.set_attr(is_set=False) else: msg = ( 'Keyword argument "state" must either be ' '"l" or "g" or be None.' ) logger.error(msg) raise TypeError(msg) # design/offdesign parameter list elif key in ['design', 'offdesign']: if not isinstance(kwargs[key], list): msg = f"Please provide the {key} parameters as list!" logger.error(msg) raise TypeError(msg) elif set(kwargs[key]).issubset(self.property_data.keys()): self.__dict__.update({key: kwargs[key]}) else: params = ', '.join(self.property_data.keys()) msg = ( "Available parameters for (off-)design specification " f"are: {params}." ) logger.error(msg) raise ValueError(msg) # design path elif key == 'design_path': if isinstance(kwargs[key], str) or kwargs[key] is None: self.__dict__.update({key: kwargs[key]}) self.new_design = True else: msg = "Provide the a string or None for 'design_path'." logger.error(msg) raise TypeError(msg) # other boolean keywords elif key in ['printout', 'local_design', 'local_offdesign']: if not isinstance(kwargs[key], bool): msg = ('Please provide the ' + key + ' as boolean.') logger.error(msg) raise TypeError(msg) else: self.__dict__.update({key: kwargs[key]}) elif key == "mixing_rule": self.mixing_rule = kwargs[key] # invalid keyword else: msg = 'Connection has no attribute ' + key + '.' logger.error(msg) raise KeyError(msg)
def _fluid_specification(self, key, value): self._check_fluid_datatypes(key, value) if key == "fluid": for fluid, fraction in value.items(): if "::" in fluid: back_end, fluid = fluid.split("::") else: back_end = None if fraction is None: if fluid in self.fluid.is_set: self.fluid.is_set.remove(fluid) self.fluid.is_var.add(fluid) else: self.fluid.val[fluid] = fraction self.fluid.is_set.add(fluid) if fluid in self.fluid.is_var: self.fluid.is_var.remove(fluid) self.fluid.back_end[fluid] = back_end elif key == "fluid0": self.fluid.val0.update(value) elif key == "fluid_engines": self.fluid.engine = value elif key == "fluid_balance": self.fluid_balance.is_set = value else: msg = f"Connections do not have an attribute named {key}" logger.error(msg) raise KeyError(msg) def _check_fluid_datatypes(self, key, value): if key == "fluid_balance": if not isinstance(value, bool): msg = "Datatype for 'fluid_balance' must be boolean." logger.error(msg) raise TypeError(msg) else: if not isinstance(value, dict): msg = "Datatype for fluid vector specification must be dict." logger.error(msg) raise TypeError(msg) def _parameter_specification(self, key, value): try: float(value) is_numeric = True except (TypeError, ValueError): is_numeric = False if value is None: self.get_attr(key).set_attr(is_set=False) if f"{key}_ref" in self.property_data: self.get_attr(f"{key}_ref").set_attr(is_set=False) if key in ["m", "p", "h"]: self.get_attr(key).is_var = True elif is_numeric: # value specification if key in self.property_data: self.get_attr(key).set_attr(is_set=True, val=value) if key in ["m", "p", "h"]: self.get_attr(key).is_var = False # starting value specification else: self.get_attr(key.replace('0', '')).set_attr(val0=value) # reference object elif isinstance(value, Ref): if f"{key}_ref" not in self.property_data: msg = f"Referencing {key} is not implemented." logger.error(msg) raise NotImplementedError(msg) else: self.get_attr(f"{key}_ref").set_attr(ref=value) self.get_attr(f"{key}_ref").set_attr(is_set=True) # invalid datatype for keyword else: msg = f"Wrong datatype for keyword argument {key}." logger.error(msg) raise TypeError(msg)
[docs] def get_attr(self, key): r""" Get the value of a connection's attribute. Parameters ---------- key : str The attribute you want to retrieve. Returns ------- out : Specified attribute. """ if key in self.__dict__: return self.__dict__[key] else: msg = 'Connection has no attribute \"' + key + '\".' logger.error(msg) raise KeyError(msg)
[docs] def serialize(self): export = {} export.update({"source": self.source.label}) export.update({"target": self.target.label}) for k in self._serializable(): export.update({k: self.get_attr(k)}) for k in self.property_data: data = self.get_attr(k) export.update({k: data.serialize()}) export.update({"state": self.state.serialize()}) return {self.label: export}
@staticmethod def _serializable(): return [ "source_id", "target_id", "design_path", "design", "offdesign", "local_design", "local_design", "printout", "mixing_rule" ] def _create_fluid_wrapper(self): for fluid in self.fluid.val: if fluid in self.fluid.wrapper: continue if fluid not in self.fluid.engine: self.fluid.engine[fluid] = CoolPropWrapper back_end = None if fluid in self.fluid.back_end: back_end = self.fluid.back_end[fluid] else: self.fluid.back_end[fluid] = None self.fluid.wrapper[fluid] = self.fluid.engine[fluid](fluid, back_end)
[docs] def preprocess(self): self.num_eq = 0 self.it = 0 self.equations = {} for parameter in self.parameters: container = self.get_attr(parameter) if container.is_set and not container._solved: self.equations[self.num_eq] = parameter self.num_eq += self.parameters[parameter].num_eq elif container._solved: container._solved = False self.residual = np.zeros(self.num_eq) self.jacobian = {}
[docs] def simplify_specifications(self): systemvar_specs = [] nonsystemvar_specs = [] for name, container in self.property_data.items(): if container.is_set: if name in ["m", "p", "h"]: systemvar_specs += [name] elif name in ["T", "x", "Td_bp", "v"]: nonsystemvar_specs += [name] specs = set(systemvar_specs + nonsystemvar_specs) num_specs = len(specs) if num_specs > 3: inputs = ", ".join(specs) msg = ( "You have specified more than 3 parameters for the connection " f"{self.label} with a known fluid compoistion: {inputs}. This " "overdetermines the state of the fluid." ) raise TESPyNetworkError(msg) if not self.h.is_set and self.p.is_set: if self.T.is_set: self.h.val_SI = h_mix_pT(self.p.val_SI, self.T.val_SI, self.fluid_data, self.mixing_rule) self.h._solved = True self.T._solved = True elif self.Td_bp.is_set: T_sat = T_sat_p(self.p.val_SI, self.fluid_data) self.h.val_SI = h_mix_pT(self.p.val_SI, T_sat + self.Td_bp.val, self.fluid_data) self.h._solved = True self.Td_bp._solved = True elif self.x.is_set: self.h.val_SI = h_mix_pQ(self.p.val_SI, self.x.val_SI, self.fluid_data) self.h._solved = True self.x._solved = True elif not self.h.is_set and not self.p.is_set: if self.T.is_set and self.x.is_set: self.p.val_SI = p_sat_T(self.T.val_SI, self.fluid_data) self.h.val_SI = h_mix_pQ(self.p.val_SI, self.x.val_SI, self.fluid_data) self.T._solved = True self.x._solved = True self.p._solved = True self.h._solved = True
[docs] def get_parameters(self): return { "m": dc_prop(is_var=True), "p": dc_prop(is_var=True), "h": dc_prop(is_var=True), "vol": dc_prop(), "s": dc_prop(), "fluid": dc_flu(), "fluid_balance": dc_simple( func=self.fluid_balance_func, deriv=self.fluid_balance_deriv, val=False, num_eq=1 ), "T": dc_prop(func=self.T_func, deriv=self.T_deriv, num_eq=1), "v": dc_prop(func=self.v_func, deriv=self.v_deriv, num_eq=1), "x": dc_prop(func=self.x_func, deriv=self.x_deriv, num_eq=1), "Td_bp": dc_prop( func=self.Td_bp_func, deriv=self.Td_bp_deriv, num_eq=1 ), "m_ref": dc_ref( func=self.primary_ref_func, deriv=self.primary_ref_deriv, num_eq=1, func_params={"variable": "m"} ), "p_ref": dc_ref( func=self.primary_ref_func, deriv=self.primary_ref_deriv, num_eq=1, func_params={"variable": "p"} ), "h_ref": dc_ref( func=self.primary_ref_func, deriv=self.primary_ref_deriv, num_eq=1, func_params={"variable": "h"} ), "T_ref": dc_ref( func=self.T_ref_func, deriv=self.T_ref_deriv, num_eq=1 ), "v_ref": dc_ref( func=self.v_ref_func, deriv=self.v_ref_deriv, num_eq=1 ), }
[docs] def build_fluid_data(self): self.fluid_data = { fluid: { "wrapper": self.fluid.wrapper[fluid], "mass_fraction": self.fluid.val[fluid] } for fluid in self.fluid.val }
[docs] def primary_ref_func(self, k, **kwargs): variable = kwargs["variable"] self.get_attr(variable) ref = self.get_attr(f"{variable}_ref").ref self.residual[k] = ( self.get_attr(variable).val_SI - (ref.obj.get_attr(variable).val_SI * ref.factor + ref.delta_SI) )
[docs] def primary_ref_deriv(self, k, **kwargs): variable = kwargs["variable"] ref = self.get_attr(f"{variable}_ref").ref if self.get_attr(variable).is_var: self.jacobian[k, self.get_attr(variable).J_col] = 1 if ref.obj.get_attr(variable).is_var: self.jacobian[k, ref.obj.get_attr(variable).J_col] = -ref.factor
[docs] def calc_T(self, T0=None): if T0 is None: T0 = self.T.val_SI return T_mix_ph(self.p.val_SI, self.h.val_SI, self.fluid_data, self.mixing_rule, T0=T0)
[docs] def T_func(self, k, **kwargs): self.residual[k] = self.calc_T() - self.T.val_SI
[docs] def T_deriv(self, k, **kwargs): if self.p.is_var: self.jacobian[k, self.p.J_col] = ( dT_mix_dph(self.p.val_SI, self.h.val_SI, self.fluid_data, self.mixing_rule, self.T.val_SI) ) if self.h.is_var: self.jacobian[k, self.h.J_col] = ( dT_mix_pdh(self.p.val_SI, self.h.val_SI, self.fluid_data, self.mixing_rule, self.T.val_SI) ) for fluid in self.fluid.is_var: self.jacobian[k, self.fluid.J_col[fluid]] = dT_mix_ph_dfluid( self.p.val_SI, self.h.val_SI, fluid, self.fluid_data, self.mixing_rule )
[docs] def T_ref_func(self, k, **kwargs): ref = self.T_ref.ref self.residual[k] = ( self.calc_T() - (ref.obj.calc_T() * ref.factor + ref.delta_SI) )
[docs] def T_ref_deriv(self, k, **kwargs): # first part of sum is identical to direct temperature specification self.T_deriv(k, **kwargs) ref = self.T_ref.ref if ref.obj.p.is_var: self.jacobian[k, ref.obj.p.J_col] = -( dT_mix_dph(ref.obj.p.val_SI, ref.obj.h.val_SI, ref.obj.fluid_data, ref.obj.mixing_rule) ) * ref.factor if ref.obj.h.is_var: self.jacobian[k, ref.obj.h.J_col] = -( dT_mix_pdh(ref.obj.p.val_SI, ref.obj.h.val_SI, ref.obj.fluid_data, ref.obj.mixing_rule) ) * ref.factor for fluid in ref.obj.fluid.is_var: if not self._increment_filter[ref.obj.fluid.J_col[fluid]]: self.jacobian[k, ref.obj.fluid.J_col[fluid]] = -dT_mix_ph_dfluid( ref.obj.p.val_SI, ref.obj.h.val_SI, fluid, ref.obj.fluid_data, ref.obj.mixing_rule )
[docs] def calc_viscosity(self, T0=None): try: return viscosity_mix_ph(self.p.val_SI, self.h.val_SI, self.fluid_data, self.mixing_rule, T0=T0) except NotImplementedError: return np.nan
[docs] def calc_vol(self, T0=None): try: return v_mix_ph(self.p.val_SI, self.h.val_SI, self.fluid_data, self.mixing_rule, T0=T0) except NotImplementedError: return np.nan
[docs] def v_func(self, k, **kwargs): self.residual[k] = self.calc_vol(T0=self.T.val_SI) * self.m.val_SI - self.v.val_SI
[docs] def v_deriv(self, k, **kwargs): if self.m.is_var: self.jacobian[k, self.m.J_col] = self.calc_vol(T0=self.T.val_SI) if self.p.is_var: self.jacobian[k, self.p.J_col] = dv_mix_dph(self.p.val_SI, self.h.val_SI, self.fluid_data) * self.m.val_SI if self.h.is_var: self.jacobian[k, self.h.J_col] = dv_mix_pdh(self.p.val_SI, self.h.val_SI, self.fluid_data) * self.m.val_SI
[docs] def v_ref_func(self, k, **kwargs): ref = self.v_ref.ref self.residual[k] = ( self.calc_vol(T0=self.T.val_SI) * self.m.val_SI - (ref.obj.calc_vol(T0=ref.obj.T.val_SI) * ref.obj.m.val_SI * ref.factor + ref.delta_SI) )
[docs] def v_ref_deriv(self, k, **kwargs): # first part of sum is identical to direct volumetric flow specification self.v_deriv(k, **kwargs) ref = self.v_ref.ref if ref.obj.m.is_var: self.jacobian[k, ref.obj.m.J_col] = -( ref.obj.calc_vol(T0=ref.obj.T.val_SI) * ref.factor ) if ref.obj.p.is_var: self.jacobian[k, ref.obj.p.J_col] = -( dv_mix_dph(ref.obj.p.val_SI, ref.obj.h.val_SI, ref.obj.fluid_data) * ref.obj.m.val_SI * ref.factor ) if ref.obj.h.is_var: self.jacobian[k, ref.obj.h.J_col] = -( dv_mix_pdh(ref.obj.p.val_SI, ref.obj.h.val_SI, ref.obj.fluid_data) * ref.obj.m.val_SI * ref.factor )
[docs] def calc_x(self): try: return Q_mix_ph(self.p.val_SI, self.h.val_SI, self.fluid_data) except NotImplementedError: return np.nan
[docs] def x_func(self, k, **kwargs): # saturated steam fraction self.residual[k] = self.h.val_SI - h_mix_pQ(self.p.val_SI, self.x.val_SI, self.fluid_data)
[docs] def x_deriv(self, k, **kwargs): if self.p.is_var: self.jacobian[k, self.p.J_col] = -dh_mix_dpQ(self.p.val_SI, self.x.val_SI, self.fluid_data) if self.h.is_var: self.jacobian[k, self.h.J_col] = 1
[docs] def calc_T_sat(self): try: return T_sat_p(self.p.val_SI, self.fluid_data) except NotImplementedError: return np.nan
[docs] def calc_Td_bp(self): try: return self.calc_T() - T_sat_p(self.p.val_SI, self.fluid_data) except NotImplementedError: return np.nan
[docs] def Td_bp_func(self, k, **kwargs): # temperature difference to boiling point self.residual[k] = self.calc_Td_bp() - self.Td_bp.val_SI
[docs] def Td_bp_deriv(self, k, **kwargs): if self.p.is_var: self.jacobian[k, self.p.J_col] = ( dT_mix_dph(self.p.val_SI, self.h.val_SI, self.fluid_data) - dT_sat_dp(self.p.val_SI, self.fluid_data) ) if self.h.is_var: self.jacobian[k, self.h.J_col] = dT_mix_pdh( self.p.val_SI, self.h.val_SI, self.fluid_data )
[docs] def fluid_balance_func(self, k, **kwargs): residual = 1 - sum(self.fluid.val[f] for f in self.fluid.is_set) residual -= sum(self.fluid.val[f] for f in self.fluid.is_var) self.residual[k] = residual
[docs] def fluid_balance_deriv(self, k, **kwargs): for f in self.fluid.is_var: self.jacobian[k, self.fluid.J_col[f]] = -self.fluid.val[f]
[docs] def calc_s(self): try: return s_mix_ph(self.p.val_SI, self.h.val_SI, self.fluid_data, self.mixing_rule, T0=self.T.val_SI) except NotImplementedError: return np.nan
[docs] def calc_Q(self): return Q_mix_ph(self.p.val_SI, self.h.val_SI, self.fluid_data)
[docs] def solve(self, increment_filter): self._increment_filter = increment_filter for k, parameter in self.equations.items(): data = self.get_attr(parameter) data.func(k, **data.func_params) data.deriv(k, **data.func_params)
[docs] def calc_results(self): self.T.val_SI = self.calc_T() number_fluids = get_number_of_fluids(self.fluid_data) _converged = True if number_fluids > 1: h_from_T = h_mix_pT(self.p.val_SI, self.T.val_SI, self.fluid_data, self.mixing_rule) if abs(h_from_T - self.h.val_SI) > ERR ** .5: self.T.val_SI = np.nan self.vol.val_SI = np.nan self.v.val_SI = np.nan self.s.val_SI = np.nan msg = ( "Could not find a feasible value for mixture temperature at " f"connection {self.label}. The values for temperature, " "specific volume, volumetric flow and entropy are set to nan." ) logger.error(msg) _converged = False else: _, Tmax = get_mixture_temperature_range(self.fluid_data) if self.T.val_SI > Tmax: msg = ( "The temperature value of the mixture is above the " "upper temperature limit of a mixture component. The " "resulting temperature may have larger deviations " "compared to the tolerance specified in the " "corresponding substance property library." ) logger.warning(msg) else: try: if not self.x.is_set: self.x.val_SI = self.calc_x() except ValueError: self.x.val_SI = np.nan try: if not self.Td_bp.is_set: self.Td_bp.val_SI = self.calc_Td_bp() except ValueError: self.x.val_SI = np.nan if _converged: self.vol.val_SI = self.calc_vol() self.v.val_SI = self.vol.val_SI * self.m.val_SI self.s.val_SI = self.calc_s() for prop in fpd.keys(): self.get_attr(prop).val = convert_from_SI( prop, self.get_attr(prop).val_SI, self.get_attr(prop).unit ) self.m.val0 = self.m.val self.p.val0 = self.p.val self.h.val0 = self.h.val self.fluid.val0 = self.fluid.val.copy()
[docs] def check_pressure_bounds(self, fluid): if self.p.val_SI > self.fluid.wrapper[fluid]._p_max: self.p.val_SI = self.fluid.wrapper[fluid]._p_max logger.debug(self._property_range_message('p')) elif self.p.val_SI < self.fluid.wrapper[fluid]._p_min: try: # if this works, the temperature is higher than the minimum # temperature, we can access pressure values below minimum # pressure self.fluid.wrapper[fluid].T_ph(self.p.val_SI, self.h.val_SI) except ValueError: self.p.val_SI = self.fluid.wrapper[fluid]._p_min + 1e1 logger.debug(self._property_range_message('p'))
[docs] def check_enthalpy_bounds(self, fluid): # enthalpy try: hmin = self.fluid.wrapper[fluid].h_pT( self.p.val_SI, self.fluid.wrapper[fluid]._T_min + 1e-1 ) except ValueError: f = 1.05 hmin = self.fluid.wrapper[fluid].h_pT( self.p.val_SI, self.fluid.wrapper[fluid]._T_min * f ) if self.h.val_SI < hmin: if hmin < 0: self.h.val_SI = hmin * 0.9999 else: self.h.val_SI = hmin * 1.0001 logger.debug(self._property_range_message('h')) else: T = self.fluid.wrapper[fluid]._T_max while True: try: hmax = self.fluid.wrapper[fluid].h_pT(self.p.val_SI, T) break except ValueError as e: T *= 0.99 if T < self.fluid.wrapper[fluid]._T_min: raise ValueError(e) from e if self.h.val_SI > hmax: self.h.val_SI = hmax * 0.9999 logger.debug(self._property_range_message('h'))
[docs] def check_two_phase_bounds(self, fluid): if (self.Td_bp.val_SI > 0 or (self.state.val == 'g' and self.state.is_set)): h = self.fluid.wrapper[fluid].h_pQ(self.p.val_SI, 1) if self.h.val_SI < h: self.h.val_SI = h * 1.01 logger.debug(self._property_range_message('h')) elif (self.Td_bp.val_SI < 0 or (self.state.val == 'l' and self.state.is_set)): h = self.fluid.wrapper[fluid].h_pQ(self.p.val_SI, 0) if self.h.val_SI > h: self.h.val_SI = h * 0.99 logger.debug(self._property_range_message('h'))
[docs] def check_temperature_bounds(self): r""" Check if temperature is within user specified limits. Parameters ---------- c : tespy.connections.connection.Connection Connection to check fluid properties. """ Tmin = max( [w._T_min for f, w in self.fluid.wrapper.items() if self.fluid.val[f] > ERR] ) * 1.01 Tmax = min( [w._T_max for f, w in self.fluid.wrapper.items() if self.fluid.val[f] > ERR] ) * 0.99 hmin = h_mix_pT(self.p.val_SI, Tmin, self.fluid_data, self.mixing_rule) hmax = h_mix_pT(self.p.val_SI, Tmax, self.fluid_data, self.mixing_rule) if self.h.val_SI < hmin: self.h.val_SI = hmin logger.debug(self._property_range_message('h')) if self.h.val_SI > hmax: self.h.val_SI = hmax logger.debug(self._property_range_message('h'))
def _property_range_message(self, prop): r""" Return debugging message for fluid property range adjustments. Parameters ---------- c : tespy.connections.connection.Connection Connection to check fluid properties. prop : str Fluid property. Returns ------- msg : str Debugging message. """ msg = ( f"{fpd[prop]['text'][0].upper()}{fpd[prop]['text'][1:]} out of " f"fluid property range at connection {self.label}, adjusting value " f"to {self.get_attr(prop).val_SI} {fpd[prop]['SI_unit']}." ) return msg
[docs] def get_physical_exergy(self, pamb, Tamb): r""" Get the value of a connection's specific physical exergy. Parameters ---------- p0 : float Ambient pressure p0 / Pa. T0 : float Ambient temperature T0 / K. Note ---- .. math:: e^\mathrm{PH} = e^\mathrm{T} + e^\mathrm{M}\\ E^\mathrm{T} = \dot{m} \cdot e^\mathrm{T}\\ E^\mathrm{M} = \dot{m} \cdot e^\mathrm{M}\\ E^\mathrm{PH} = \dot{m} \cdot e^\mathrm{PH} """ self.ex_therm, self.ex_mech = fp.functions.calc_physical_exergy( self.h.val_SI, self.s.val_SI, self.p.val_SI, pamb, Tamb, self.fluid_data, self.mixing_rule, self.T.val_SI ) self.Ex_therm = self.ex_therm * self.m.val_SI self.Ex_mech = self.ex_mech * self.m.val_SI self.ex_physical = self.ex_therm + self.ex_mech self.Ex_physical = self.m.val_SI * self.ex_physical
[docs] def get_chemical_exergy(self, pamb, Tamb, Chem_Ex): r""" Get the value of a connection's specific chemical exergy. Parameters ---------- p0 : float Ambient pressure p0 / Pa. T0 : float Ambient temperature T0 / K. Chem_Ex : dict Lookup table for standard specific chemical exergy. Note ---- .. math:: E^\mathrm{CH} = \dot{m} \cdot e^\mathrm{CH} """ if Chem_Ex is None: self.ex_chemical = 0 else: self.ex_chemical = fp.functions.calc_chemical_exergy( pamb, Tamb, self.fluid_data, Chem_Ex, self.mixing_rule, self.T.val_SI ) self.Ex_chemical = self.m.val_SI * self.ex_chemical
[docs] class Ref: r""" A reference object is used to reference (unknown) properties of connections to other connections. For example, reference the mass flow of one connection :math:`\dot{m}` to another mass flow :math:`\dot{m}_{ref}`: .. math:: \dot{m} = \dot{m}_\mathrm{ref} \cdot \mathrm{factor} + \mathrm{delta} Parameters ---------- obj : tespy.connections.connection.Connection Connection to be referenced. factor : float Factor to multiply specified property with. delta : float Delta to add after multiplication. """ def __init__(self, ref_obj, factor, delta): if not isinstance(ref_obj, Connection): msg = 'First parameter must be object of type connection.' logger.error(msg) raise TypeError(msg) if not (isinstance(factor, int) or isinstance(factor, float)): msg = 'Second parameter must be of type int or float.' logger.error(msg) raise TypeError(msg) if not (isinstance(delta, int) or isinstance(delta, float)): msg = 'Thrid parameter must be of type int or float.' logger.error(msg) raise TypeError(msg) self.obj = ref_obj self.factor = factor self.delta = delta self.delta_SI = None msg = ( f"Created reference object with factor {self.factor} and delta " f"{self.delta} referring to connection {ref_obj.label}" ) logger.debug(msg)
[docs] def get_attr(self, key): r""" Get the value of a reference attribute. Parameters ---------- key : str The attribute you want to retrieve. Returns ------- out : Specified attribute. """ if key in self.__dict__: return self.__dict__[key] else: msg = 'Reference has no attribute \"' + key + '\".' logger.error(msg) raise KeyError(msg)