Source code for tespy.networks.network_reader

# -*- coding: utf-8

"""Module for loading a tespy network from saved state.

Use the method :func:`tespy.networks.network_reader.load_network` for importing
a network from a saved state.


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/networks/network_reader.py

SPDX-License-Identifier: MIT
"""
import importlib
import json
import os

from tespy.components.component import component_registry
from tespy.connections import Bus
from tespy.connections import Connection
from tespy.connections import Ref
from tespy.networks.network import Network
from tespy.tools import logger
from tespy.tools.characteristics import CharLine
from tespy.tools.characteristics import CharMap
from tespy.tools.data_containers import ComponentCharacteristicMaps as dc_cm
from tespy.tools.data_containers import ComponentCharacteristics as dc_cc
from tespy.tools.data_containers import DataContainer as dc
from tespy.tools.data_containers import FluidProperties as dc_prop
from tespy.tools.fluid_properties.wrappers import wrapper_registry


[docs] def load_network(path): r""" Load a network from a base path. Parameters ---------- path : str The path to the network data. Returns ------- nw : tespy.networks.network.Network TESPy networks object. Note ---- If you export the network structure of an existing TESPy network, it will be saved to the path you specified. The structure of the saved data in that path is the structure you need to provide in the path for loading the network. The structure of the path must be as follows: - Folder: path (e.g. 'mynetwork') - Subfolder: components ('mynetwork/components') containing {component_class_name}.json (e.g. HeatExchanger.json) - connections.json - busses.json - network.json Example ------- Create a network and export it. This is followed by loading the network with the network_reader module. All network information stored will be passed to a new network object. Components, connections and busses will be accessible by label. The following example setup is simple gas turbine setup with compressor, combustion chamber and turbine. The fuel is fed from a pipeline and throttled to the required pressure while keeping the temperature at a constant value. >>> from tespy.components import (Sink, Source, CombustionChamber, ... Compressor, Turbine, SimpleHeatExchanger) >>> from tespy.connections import Connection, Ref, Bus >>> from tespy.networks import load_network, Network >>> import shutil >>> nw = Network(p_unit='bar', T_unit='C', h_unit='kJ / kg', iterinfo=False) >>> air = Source('air') >>> f = Source('fuel') >>> c = Compressor('compressor') >>> comb = CombustionChamber('combustion') >>> t = Turbine('turbine') >>> p = SimpleHeatExchanger('fuel preheater') >>> si = Sink('sink') >>> inc = Connection(air, 'out1', c, 'in1', label='ambient air') >>> cc = Connection(c, 'out1', comb, 'in1') >>> fp = Connection(f, 'out1', p, 'in1') >>> pc = Connection(p, 'out1', comb, 'in2') >>> ct = Connection(comb, 'out1', t, 'in1') >>> outg = Connection(t, 'out1', si, 'in1') >>> nw.add_conns(inc, cc, fp, pc, ct, outg) Specify component and connection properties. The intlet pressure at the compressor and the outlet pressure after the turbine are identical. For the compressor, the pressure ratio and isentropic efficiency are design parameters. A compressor map (efficiency vs. mass flow and pressure rise vs. mass flow) is selected for the compressor. Fuel is Methane. >>> c.set_attr(pr=10, eta_s=0.88, design=['eta_s', 'pr'], ... offdesign=['char_map_eta_s', 'char_map_pr']) >>> t.set_attr(eta_s=0.9, design=['eta_s'], ... offdesign=['eta_s_char', 'cone']) >>> comb.set_attr(lamb=2) >>> inc.set_attr(fluid={'N2': 0.7556, 'O2': 0.2315, 'Ar': 0.0129}, T=25, p=1) >>> fp.set_attr(fluid={'CH4': 0.96, 'CO2': 0.04}, T=25, p=40) >>> pc.set_attr(T=25) >>> outg.set_attr(p=Ref(inc, 1, 0)) >>> power = Bus('total power output') >>> power.add_comps({"comp": c, "base": "bus"}, {"comp": t}) >>> nw.add_busses(power) For a stable start, we specify the fresh air mass flow. >>> inc.set_attr(m=3) >>> nw.solve('design') The total power output is set to 1 MW, electrical or mechanical efficiencies are not considered in this example. The documentation example in class :py:class:`tespy.connections.bus.Bus` provides more information on efficiencies of generators, for instance. >>> comb.set_attr(lamb=None) >>> ct.set_attr(T=1100) >>> inc.set_attr(m=None) >>> power.set_attr(P=-1e6) >>> nw.solve('design') >>> nw.lin_dep False >>> nw.save('design_state') >>> nw.export('exported_nwk') >>> mass_flow = round(nw.get_conn('ambient air').m.val_SI, 1) >>> c.set_attr(igva='var') >>> nw.solve('offdesign', design_path='design_state') >>> round(t.eta_s.val, 1) 0.9 >>> power.set_attr(P=-0.75e6) >>> nw.solve('offdesign', design_path='design_state') >>> nw.lin_dep False >>> eta_s_t = round(t.eta_s.val, 3) >>> igva = round(c.igva.val, 3) >>> eta_s_t 0.898 >>> igva 20.138 The designed network is exported to the path 'exported_nwk'. Now import the network and recalculate. Check if the results match with the previous calculation in design and offdesign case. >>> imported_nwk = load_network('exported_nwk') >>> imported_nwk.set_attr(iterinfo=False) >>> imported_nwk.solve('design') >>> imported_nwk.lin_dep False >>> round(imported_nwk.get_conn('ambient air').m.val_SI, 1) == mass_flow True >>> round(imported_nwk.get_comp('turbine').eta_s.val, 3) 0.9 >>> imported_nwk.get_comp('compressor').set_attr(igva='var') >>> imported_nwk.solve('offdesign', design_path='design_state') >>> round(imported_nwk.get_comp('turbine').eta_s.val, 3) 0.9 >>> imported_nwk.busses['total power output'].set_attr(P=-0.75e6) >>> imported_nwk.solve('offdesign', design_path='design_state') >>> round(imported_nwk.get_comp('turbine').eta_s.val, 3) == eta_s_t True >>> round(imported_nwk.get_comp('compressor').igva.val, 3) == igva True >>> shutil.rmtree('./exported_nwk', ignore_errors=True) >>> shutil.rmtree('./design_state', ignore_errors=True) """ path_comps = os.path.join(path, 'components') msg = f'Reading network data from base path {path}.' logger.info(msg) # load components comps = {} module_name = "tespy.components" _ = importlib.import_module(module_name) files = os.listdir(path_comps) for f in files: if not f.endswith(".json"): continue component = f.replace(".json", "") if component not in component_registry.items: msg = ( f"A class {component} is not available through the " "tespy.components.component.component_registry decorator. " "If you are using a custom component make sure to decorate the " "class." ) logger.warning(msg) continue fn = os.path.join(path_comps, f) msg = f"Reading component data ({component}) from {fn}." logger.debug(msg) with open(fn, "r", encoding="utf-8") as c: data = json.load(c) target_class = component_registry.items[component] comps.update(_construct_components(target_class, data)) msg = 'Created network components.' logger.info(msg) # create network nw = _construct_network(path) # load connections fn = os.path.join(path, 'connections.json') msg = f"Reading connection data from {fn}." logger.debug(msg) with open(fn, "r", encoding="utf-8") as c: data = json.load(c) conns = _construct_connections(data, comps) # add connections to network for c in conns.values(): nw.add_conns(c) msg = 'Created connections.' logger.info(msg) # load busses fn = os.path.join(path, 'busses.json') if os.path.isfile(fn): msg = f"Reading bus data from {fn}." logger.debug(msg) with open(fn, "r", encoding="utf-8") as c: data = json.load(c) busses = _construct_busses(data, comps) # add busses to network for b in busses.values(): nw.add_busses(b) msg = 'Created busses.' logger.info(msg) else: msg = 'No bus data found!' logger.debug(msg) msg = 'Created network.' logger.info(msg) nw.check_network() return nw
def _construct_components(target_class, data): r""" Create TESPy component from class name and set parameters. Parameters ---------- component : str Name of the component class to be constructed. data : dict Dictionary with component information. Returns ------- dict Dictionary of all components of the specified type. """ instances = {} for cp, cp_data in data.items(): instances[cp] = target_class(cp) for param, param_data in cp_data.items(): container = instances[cp].get_attr(param) if isinstance(container, dc): if "char_func" in param_data: if isinstance(container, dc_cc): param_data["char_func"] = CharLine(**param_data["char_func"]) elif isinstance(container, dc_cm): param_data["char_func"] = CharMap(**param_data["char_func"]) if isinstance(container, dc_prop): param_data["val0"] = param_data["val"] container.set_attr(**param_data) else: instances[cp].set_attr(**{param: param_data}) return instances def _construct_network(path): r""" Create TESPy network from the path provided by the user. Parameters ---------- path : str Base-path to stored network data. Returns ------- nw : tespy.networks.network.Network TESPy network object. """ # read network .json-file fn = os.path.join(path, 'network.json') with open(fn, 'r') as f: data = json.load(f) # create network object with its properties return Network(**data) def _construct_connections(data, comps): r""" Create TESPy connection from data in the .json-file and its parameters. Parameters ---------- data : dict Dictionary with connection data. comps : dict Dictionary of constructed components. Returns ------- dict Dictionary of TESPy connection objects. """ conns = {} arglist = [ _ for _ in data[list(data.keys())[0]] if _ not in ["source", "source_id", "target", "target_id", "label", "fluid"] and "ref" not in _ ] arglist_ref = [_ for _ in data[list(data.keys())[0]] if "ref" in _] module_name = "tespy.tools.fluid_properties.wrappers" _ = importlib.import_module(module_name) for label, conn in data.items(): conns[label] = Connection( comps[conn["source"]], conn["source_id"], comps[conn["target"]], conn["target_id"], label=label ) for arg in arglist: container = conns[label].get_attr(arg) if isinstance(container, dc): container.set_attr(**conn[arg]) else: conns[label].set_attr(**{arg: conn[arg]}) for f, engine in conn["fluid"]["engine"].items(): conn["fluid"]["engine"][f] = wrapper_registry.items[engine] conns[label].fluid.set_attr(**conn["fluid"]) conns[label]._create_fluid_wrapper() for label, conn in data.items(): for arg in arglist_ref: if len(conn[arg]) > 0: param = arg.replace("_ref", "") ref = Ref( conns[conn[arg]["conn"]], conn[arg]["factor"], conn[arg]["delta"] ) conns[label].set_attr(**{param: ref}) return conns def _construct_busses(data, comps): r""" Create busses of the network. Parameters ---------- data : dict Bus information from .json file. comps : dict TESPy components dictionary. Returns ------- dict Dict with TESPy bus objects. """ busses = {} for label, bus_data in data.items(): busses[label] = Bus(label) busses[label].P.set_attr(**bus_data["P"]) components = [_ for _ in bus_data if _ != "P"] for cp in components: char = CharLine(**bus_data[cp]["char"]) component_data = { "comp": comps[cp], "param": bus_data[cp]["param"], "base": bus_data[cp]["base"], "char": char } busses[label].add_comps(component_data) return busses