Source code for tespy.components.heat_exchangers.solar_collector

# -*- coding: utf-8

"""Module of class SolarCollector.


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/heat_exchangers/solar_collector.py

SPDX-License-Identifier: MIT
"""

from tespy.components.component import component_registry
from tespy.components.heat_exchangers.simple import SimpleHeatExchanger
from tespy.tools.data_containers import ComponentProperties as dc_cp
from tespy.tools.data_containers import GroupedComponentProperties as dc_gcp
from tespy.tools.document_models import generate_latex_eq


[docs] @component_registry class SolarCollector(SimpleHeatExchanger): r""" The solar collector calculates heat output from irradiance. **Mandatory Equations** - :py:meth:`tespy.components.component.Component.fluid_func` - :py:meth:`tespy.components.component.Component.mass_flow_func` **Optional Equations** - :py:meth:`tespy.components.component.Component.pr_func` - :py:meth:`tespy.components.component.Component.zeta_func` - :py:meth:`tespy.components.heat_exchangers.simple.SimpleHeatExchanger.energy_balance_func` - :py:meth:`tespy.components.heat_exchangers.simple.SimpleHeatExchanger.darcy_group_func` - :py:meth:`tespy.components.heat_exchangers.simple.SimpleHeatExchanger.hw_group_func` - :py:meth:`tespy.components.heat_exchangers.solar_collector.SolarCollector.energy_group_func` Inlets/Outlets - in1 - out1 Image .. image:: /api/_images/SolarCollector.svg :alt: flowsheet of the solar collector :align: center :class: only-light .. image:: /api/_images/SolarCollector_darkmode.svg :alt: flowsheet of the solar collector :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. Q : float, dict, :code:`"var"` Heat transfer, :math:`Q/\text{W}`. pr : float, dict, :code:`"var"` Outlet to inlet pressure ratio, :math:`pr/1`. zeta : float, dict, :code:`"var"` Geometry independent friction coefficient, :math:`\frac{\zeta}{D^4}/\frac{1}{\text{m}^4}`. D : float, dict, :code:`"var"` Diameter of the pipes, :math:`D/\text{m}`. L : float, dict, :code:`"var"` Length of the pipes, :math:`L/\text{m}`. ks : float, dict, :code:`"var"` Pipe's roughness, :math:`ks/\text{m}`. darcy_group : str, dict Parametergroup for pressure drop calculation based on pipes dimensions using darcy weissbach equation. ks_HW : float, dict, :code:`"var"` Pipe's roughness, :math:`ks/\text{1}`. hw_group : str, dict Parametergroup for pressure drop calculation based on pipes dimensions using hazen williams equation. E : float, dict, :code:`"var"` irradiance at tilted collector surface area, :math:`E/\frac{\text{W}}{\text{m}^2}`. eta_opt : float, dict, :code:`"var"` optical loss at surface cover, :math:`\eta_{opt}`. lkf_lin : float, dict, :code:`"var"` Linear thermal loss key figure, :math:`\alpha_1/\frac{\text{W}}{\text{K} \cdot \text{m}^2}`. lkf_quad : float, dict, :code:`"var"` Quadratic thermal loss key figure, :math:`\alpha_2/\frac{\text{W}}{\text{K}^2 \cdot \text{m}^2}`. A : float, dict, :code:`"var"` Collector surface area :math:`A/\text{m}^2`. Tamb : float, dict Ambient temperature, provide parameter in network's temperature unit. energy_group : str, dict Parametergroup for energy balance of solarthermal collector. Example ------- The solar collector is used to calculate heat transferred to the heating system from irradiance on a tilted plane. For instance, it is possible to calculate the collector surface area required to transfer a specific amount of heat at a given irradiance. The collector parameters are the linear and the quadratic loss keyfigure as well as the optical effifiency. >>> from tespy.components import Sink, Source, SolarCollector >>> from tespy.connections import Connection >>> from tespy.networks import Network >>> import shutil >>> nw = Network() >>> nw.set_attr(p_unit='bar', T_unit='C', h_unit='kJ / kg', iterinfo=False) >>> so = Source('source') >>> si = Sink('sink') >>> sc = SolarCollector('solar collector') >>> sc.component() 'solar collector' >>> sc.set_attr(pr=0.95, Q=1e4, design=['pr', 'Q'], offdesign=['zeta'], ... Tamb=25, A='var', eta_opt=0.92, lkf_lin=1, lkf_quad=0.005, E=8e2) >>> inc = Connection(so, 'out1', sc, 'in1') >>> outg = Connection(sc, 'out1', si, 'in1') >>> nw.add_conns(inc, outg) The outlet temperature should be at 90 °C at a constant mass flow, which is determined in the design calculation. In offdesign operation (at a different irradiance) using the calculated surface area and mass flow, it is possible to predict the outlet temperature. It would instead be possible to calulate the change in mass flow required to hold the specified outlet temperature, too. >>> inc.set_attr(fluid={'H2O': 1}, T=40, p=3, offdesign=['m']) >>> outg.set_attr(T=90, design=['T']) >>> nw.solve('design') >>> nw.save('tmp') >>> round(sc.A.val, 1) 14.5 >>> sc.set_attr(A=sc.A.val, E=5e2, Tamb=20) >>> nw.solve('offdesign', design_path='tmp') >>> round(sc.Q.val, 1) 6083.8 >>> round(outg.T.val, 1) 70.5 >>> shutil.rmtree('./tmp', ignore_errors=True) """
[docs] @staticmethod def component(): return 'solar collector'
[docs] def get_parameters(self): data = super().get_parameters() for k in ["kA_group", "kA_char_group", "kA", "kA_char"]: del data[k] data.update({ 'E': dc_cp(min_val=0), 'A': dc_cp(min_val=0), 'eta_opt': dc_cp(min_val=0, max_val=1), 'lkf_lin': dc_cp(min_val=0), 'lkf_quad': dc_cp(min_val=0), 'Tamb': dc_cp(), 'Q_loss': dc_cp(max_val=0, val=0), 'energy_group': dc_gcp( elements=['E', 'eta_opt', 'lkf_lin', 'lkf_quad', 'A', 'Tamb'], num_eq=1, latex=self.energy_group_func_doc, func=self.energy_group_func, deriv=self.energy_group_deriv ) }) return data
[docs] def energy_group_func(self): r""" Equation for solar collector energy balance. Returns ------- residual : float Residual value of equation. .. math:: \begin{split} 0 = & \dot{m} \cdot \left( h_{out} - h_{in} \right)\\ & - A \cdot \left[E \cdot \eta_{opt} - \alpha_1 \cdot \left(T_m - T_{amb} \right) - \alpha_2 \cdot \left(T_m - T_{amb}\right)^2 \right]\\ T_m = & \frac{T_{out} + T_{in}}{2}\\ \end{split} Reference: :cite:`Quaschning2013`. """ i = self.inl[0] o = self.outl[0] T_m = 0.5 * (i.calc_T() + o.calc_T()) return ( i.m.val_SI * (o.h.val_SI - i.h.val_SI) - self.A.val * ( self.E.val * self.eta_opt.val - (T_m - self.Tamb.val_SI) * self.lkf_lin.val - self.lkf_quad.val * (T_m - self.Tamb.val_SI) ** 2 ) )
[docs] def energy_group_func_doc(self, label): r""" Equation for solar collector energy balance. Parameters ---------- label : str Label for equation. Returns ------- latex : str LaTeX code of equations applied. """ latex = ( r'\begin{split}' + '\n' r'0 = & \dot{m}_\mathrm{in} \cdot \left( h_\mathrm{out} - ' r'h_\mathrm{in} \right)\\' + '\n' r'& - A \cdot \left[E \cdot \eta_\mathrm{opt} - \alpha_1 \cdot' r'\left(T_\mathrm{m} - T_\mathrm{amb} \right) - \alpha_2 \cdot' r'\left(T_\mathrm{m} -T_\mathrm{amb}\right)^2 \right]\\' + '\n' r'T_\mathrm{m}=&\frac{T_\mathrm{out}+T_\mathrm{in}}{2}\\' + '\n' r'\end{split}' ) return generate_latex_eq(self, latex, label)
[docs] def energy_group_deriv(self, increment_filter, k): r""" Calculate partial derivatives of energy group function. Parameters ---------- increment_filter : ndarray Matrix for filtering non-changing variables. k : int Position of derivatives in Jacobian matrix (k-th equation). """ f = self.energy_group_func i = self.inl[0] o = self.outl[0] if self.is_variable(i.m, increment_filter): self.jacobian[k, i.m.J_col] = o.h.val_SI - i.h.val_SI if self.is_variable(i.p, increment_filter): self.jacobian[k, i.p.J_col] = self.numeric_deriv(f, 'p', i) if self.is_variable(i.h, increment_filter): self.jacobian[k, i.h.J_col] = self.numeric_deriv(f, 'h', i) if self.is_variable(o.p, increment_filter): self.jacobian[k, o.p.J_col] = self.numeric_deriv(f, 'p', o) if self.is_variable(o.h, increment_filter): self.jacobian[k, o.h.J_col] = self.numeric_deriv(f, 'h', o) # custom variables for the energy-group for variable_name in self.energy_group.elements: parameter = self.get_attr(variable_name) if parameter == self.Tamb: continue if parameter.is_var: self.jacobian[k, parameter.J_col] = ( self.numeric_deriv(f, variable_name, None) )
[docs] def calc_parameters(self): r"""Postprocessing parameter calculation.""" i = self.inl[0] o = self.outl[0] self.Q.val = i.m.val_SI * (o.h.val_SI - i.h.val_SI) self.pr.val = o.p.val_SI / i.p.val_SI self.zeta.val = self.calc_zeta(i, o) if self.energy_group.is_set: self.Q_loss.val = -(self.E.val * self.A.val - self.Q.val) self.Q_loss.is_result = True else: self.Q_loss.is_result = False