four_element.py

# created January 2017

from __future__ import division
import math
import random
import warnings


class FourElement(object):
    """This class contains attributes and functions for four element model

    This model adds another element for the roof. Roofs commonly exhibit the
    same excitations as exterior walls but have different coefficients of heat
    transfer due to their orientation.  Thus the model distinguishes
    between internal thermal masses and exterior walls divided into
    outerwalls (vertical), rooftops and ground plates. While all exterior walls
    contribute to heat transfer to the ambient, adiabatic
    conditions apply to interior walls. This approach allows considering the
    dynamic behaviour induced by internal heat storage. This class calculates
    and holds all attributes given in documentation.

    It treats OuterWalls, Rooftops and GroundFloors separate resulting in three
    RC-combination for these.
    Depending on the chosen method it will consider an extra resistance for
    windows or merge all windows into the RC-Combination for outer walls.

    Parameters
    ----------
    thermal_zone: ThermalZone()
        TEASER instance of ThermalZone
    merge_windows : boolean
        True for merging windows into the outer wall's RC-combination,
        False for separate resistance for window, default is False. (Only
        supported for IBPSA)
    t_bt : float [d]
        Time constant according to VDI 6007 (default t_bt = 5)

    Attributes
    ----------
    Interior Walls

    area_iw : float [m2]
        Area of all interior walls.
    alpha_conv_inner_iw : float [W/(m2K)]
        Area-weighted convective coefficient of heat transfer of interior
        walls facing the inside of this thermal zone.
    alpha_rad_inner_iw : float [W/(m2K)]
        Area-weighted radiative coefficient of heat transfer of interior
        walls facing the inside of this thermal zone.
    alpha_comb_inner_iw : float [W/(m2K)]
        Area-weighted combined coefficient of heat transfer of interior walls
        facing the inside of this thermal zone.
    alpha_conv_outer_iw : float [W/(m2K)]
        Area-weighted convective coefficient of heat transfer of interior
        walls facing the adjacent thermal zone. (Currently not supported)
    alpha_rad_outer_iw : float [W/(m2K)]
        Area-weighted radiative coefficient of heat transfer of interior
        walls facing the adjacent thermal zone. (Currently not supported)
    alpha_comb_outer_iw : float [W/(m2K)]
        Area-weighted combined coefficient of heat transfer of interior walls
        facing the adjacent thermal zone. (Currently not supported)
    ua_value_iw : float [W/K]
        U-Value times interior wall area. (Does not take adjacent thermal
        zones into account)
    r_conv_inner_iw : float [K/W]
        Sum of convective resistances for all interior walls
        facing the inside of this thermal zone.
    r_rad_inner_iw : float [K/W]
        Sum of radiative resistances for all interior walls facing the
        inside of this thermal zone
    r_comb_inner_iw : float [K/W]
        Sum of combined resistances for all interior walls facing the
        inside of this thermal zone
    r1_iw : float [K/W]
        Lumped resistance of interior walls no heat transfer coefficients for
        convection and radiation are accounted in this resistance.
    c1_iw : float [J/K]
        Lumped capacity of interior walls

    Outer Walls

    area_ow : float [m2]
        Area of all outer walls .
    alpha_conv_inner_ow : float [W/(m2K)]
        Area-weighted convective coefficient of heat transfer of outer walls
        facing the inside of this thermal zone .
    alpha_rad_inner_ow : float [W/(m2K)]
        Area-weighted radiative coefficient of heat transfer of outer walls
        facing the inside of this thermal zone .
    alpha_comb_inner_ow : float [W/(m2K)]
        Area-weighted combined coefficient of heat transfer of outer walls
        facing the inside of this thermal zone .
    alpha_conv_outer_ow : float [W/(m2K)]
        Area-weighted convective coefficient of heat transfer of outer walls
        facing the ambient.
    alpha_rad_outer_ow : float [W/(m2K)]
        Area-weighted radiative coefficient of heat transfer of outer walls
        facing the ambient .
    alpha_comb_outer_ow : float [W/(m2K)]
        Area-weighted combined coefficient of heat transfer of outer walls
        facing the ambient.
    ua_value_ow : float [W/K]
        U-Value times outer wall area.
    r_conv_inner_ow : float [K/W]
        Sum of convective resistances for all outer walls facing the
        inside of this thermal zone .
    r_rad_inner_ow : float [K/W]
        Sum of radiative resistances for all outer walls facing the
        inside of this thermal zone .
    r_comb_inner_ow : float [K/W]
        Sum of combined resistances for all outer walls facing the
        inside of this thermal zone.
    r_conv_outer_ow : float [K/W]
        Sum of convective resistances for all outer walls facing the
        ambient.
    r_rad_outer_ow : float [K/W]
        Sum of radiative resistances for all outer walls facing the
        ambient.
    r_comb_outer_ow : float [K/W]
        Sum of combined resistances for all outer walls facing the
        ambient.
    r1_ow : float [K/W]
        Lumped resistance of outer walls no heat transfer coefficients for
        convection and radiation are accounted in this resistance.
    r_rest_ow : float [K/W]
        Lumped remaining resistance of outer walls between r1_ow and c1_ow no
        heat transfer coefficients for convection and radiation are accounted
        in this resistance.
    c1_ow : float [J/K]
        Lumped capacity of outer walls .
    weightfactor_ow : list of floats
        Weightfactors of outer walls (UA-Value of walls with same orientation
        and tilt divided by ua_value_ow)
    outer_wall_areas : list of floats [m2]
        Area of all outer walls in one list.
    ir_emissivity_outer_ow : float
        Area-weighted ir emissivity of outer wall facing the ambient.
    ir_emissivity_inner_ow : float
        Area-weighted ir emissivity of outer walls facing the thermal zone.
    solar_absorp_ow : float
        Area-weighted solar absorption of outer walls facing the ambient.

    Ground Floors

    area_gf : float [m2]
        Area of all ground floors.
    alpha_conv_inner_gf : float [W/(m2K)]
        Area-weighted convective coefficient of heat transfer of ground floors
        facing the inside of this thermal zone.
    alpha_rad_inner_gf : float [W/(m2K)]
        Area-weighted radiative coefficient of heat transfer of ground floors
        facing the inside of this thermal zone.
    alpha_comb_inner_gf : float [W/(m2K)]
        Area-weighted combined coefficient of heat transfer of ground floors
        facing the inside of this thermal zone.
    ua_value_gf : float [W/K]
        U-Value times ground floor area.
    r_conv_inner_gf : float [K/W]
        Sum of convective resistances for all ground floors facing the
        inside of this thermal zone.
    r_rad_inner_gf : float [K/W]
        Sum of radiative resistances for all ground floors facing the
        inside of this thermal zone.
    r_comb_inner_gf : float [K/W]
        Sum of combined resistances for all ground floors facing the
        inside of this thermal zone.
    r1_gf : float [K/W]
        Lumped resistance of ground floors no heat transfer coefficients for
        convection and radiation are accounted in this resistance.
    r_rest_gf : float [K/W]
        Lumped remaining resistance of ground floors between r1_gf and c1_gf no
        heat transfer coefficients for convection and radiation are accounted
        in this resistance.
    c1_gf : float [J/K]
        Lumped capacity of ground floors.
    weightfactor_gf : float
        Weightfactor of ground floors (UA-Value of walls with same orientation
        and tilt divided by ua_value_gf)
    ground_floor_area : float [m2]
        Area of all ground floors.
    r_rad_gf_iw : float [K/W]
        Resistance for radiative heat transfer between walls.
        TODO: needs to be checked
    ir_emissivity_inner_gf : float
        Area-weighted ir emissivity of ground floors facing the thermal zone.

    Rooftops

    area_rt : float [m2]
        Area of all rooftops .
    alpha_conv_inner_rt : float [W/(m2K)]
        Area-weighted convective coefficient of heat transfer of rooftops
        facing the inside of this thermal zone .
    alpha_rad_inner_rt : float [W/(m2K)]
        Area-weighted radiative coefficient of heat transfer of rooftops
        facing the inside of this thermal zone .
    alpha_comb_inner_rt : float [W/(m2K)]
        Area-weighted combined coefficient of heat transfer of rooftops
        facing the inside of this thermal zone .
    alpha_conv_outer_rt : float [W/(m2K)]
        Area-weighted convective coefficient of heat transfer of rooftops
        facing the ambient.
    alpha_rad_outer_rt : float [W/(m2K)]
        Area-weighted radiative coefficient of heat transfer of rooftops
        facing the ambient .
    alpha_comb_outer_rt : float [W/(m2K)]
        Area-weighted combined coefficient of heat transfer of rooftops
        facing the ambient.
    ua_value_rt : float [W/K]
        U-Value times outer wall area.
    r_conv_inner_rt : float [K/W]
        Sum of convective resistances for all rooftops facing the
        inside of this thermal zone .
    r_rad_inner_rt : float [K/W]
        Sum of radiative resistances for all rooftops facing the
        inside of this thermal zone .
    r_comb_inner_rt : float [K/W]
        Sum of combined resistances for all rooftops facing the
        inside of this thermal zone.
    r_conv_outer_rt : float [K/W]
        Sum of convective resistances for all rooftops facing the
        ambient.
    r_rad_outer_rt : float [K/W]
        Sum of radiative resistances for all rooftops facing the
        ambient.
    r_comb_outer_rt : float [K/W]
        Sum of combined resistances for all rooftops facing the
        ambient.
    r1_rt : float [K/W]
        Lumped resistance of rooftops no heat transfer coefficients for
        convection and radiation are accounted in this resistance.
    r_rest_rt : float [K/W]
        Lumped remaining resistance of rooftops between r1_rt and c1_rt no
        heat transfer coefficients for convection and radiation are accounted
        in this resistance.
    c1_rt : float [J/K]
        Lumped capacity of rooftops .
    weightfactor_rt : list of floats
        Weightfactors of rooftops (UA-Value of walls with same orientation
        and tilt divided by ua_value_rt)
    weightfactor_win_rt : list of floats
        Weightfactors of windows in rooftop. CAUTION: this will be always a
        list full of zeors, as windows are always calculated separatly.
    outer_wall_areas : list of floats [m2]
        Area of all rooftops in one list.
    r_rad_rt_iw : float [K/W]
        Resistance for radiative heat transfer between walls.
        TODO: needs to be checked
    ir_emissivity_outer_rt : float
        Area-weighted ir emissivity of outer wall facing the ambient.
    ir_emissivity_inner_rt : float
        Area-weighted ir emissivity of rooftops facing the thermal zone.
    solar_absorp_rt : float
        Area-weighted solar absorption of rooftops facing the ambient.
    tilt_rt : list of floats [degree]
        Tilt of rooftops against the horizontal.
    orientation_rt : list of floats [degree]
        Orientation of rooftops (Azimuth).
        0 - North
        90 - East
        180 - South
        270 - West

    Windows

    area_win : float [m2]
        Area of all windows.
    alpha_conv_inner_win : float [W/(m2K)]
        Area-weighted convective coefficient of heat transfer of windows
        facing the inside of this thermal zone.
    alpha_rad_inner_win : float [W/(m2K)]
        Area-weighted radiative coefficient of heat transfer of windows
        facing the inside of this thermal zone.
    alpha_comb_inner_win : float [W/(m2K)]
        Area-weighted combined coefficient of heat transfer of windows facing
        the inside of this thermal zone.
    ratio_conv_rad_inner_win : float [-]
        Ratio for windows between convective and radiative heat emission,
        given in VDI 6007-3
    alpha_conv_outer_win : float [W/(m2K)]
        Area-weighted convective coefficient of heat transfer of windows
        facing the ambient.
    alpha_rad_outer_win : float [W/(m2K)]
        Area-weighted radiative coefficient of heat transfer of windows
        facing the ambient.
    alpha_comb_outer_win : float [W/(m2K)]
        Area-weighted combined coefficient of heat transfer of windows facing
        the ambient.
    ua_value_win : float [W/K]
        U-Value times outer wall area.
    u_value_win : float [W/(m2K)]
        Area weighted U-Value of windows.
    r_conv_inner_win : float [K/W]
        Sum of convective resistances for all windows facing the
        inside of this thermal zone.
    r_rad_inner_win : float [K/W]
        Sum of radiative resistances for all windows facing the
        inside of this thermal zone.
    r_comb_inner_win : float [K/W]
        Sum of combined resistances for all windows facing the
        inside of this thermal zone.
    r_conv_outer_win : float [K/W]
        Sum of convective resistances for all windows facing the
        ambient.
    r_rad_outer_win : float [K/W]
        Sum of radiative resistances for all windows facing the
        ambient.
    r_comb_outer_win : float [K/W]
        Sum of combined resistances for all windows facing the
        ambient.
    r1_win : float [K/W]
        Lumped resistance of windows, no heat transfer coefficients for
        convection and radiation are accounted in this resistance.
    weightfactor_win : list of floats
        Weightfactors of windows (UA-Value of windows with same orientation
        and tilt divided by ua_value_win or ua_value_win+ua_value_ow,
        depending if windows is lumped/merged into the walls or not)
    window_areas : list of floats [m2]
        Area of all windows in one list, if the windows are merged into the
        outer wall this list will be full of zeros
    transparent_areas : list of floats [m2]
        Area of all transparent elements (most likely windows) in one list,
        this list will be always filled with the areas, independent if
        windows are merged into walls or not.
    solar_absorp_win : float
        Area-weighted solar absorption for windows. (typically 0.0)
    ir_emissivity_win : float
        Area-weighted ir_emissivity for windows. Can be used for windows
        facing the thermal zone and the ambient.
    weighted_g_value : float
        Area-weighted g-Value of all windows.
    g_sunblind : list of floats
        G-Value of all sunblinds of each window in a list

    Misc values:

    alpha_rad_inner_mean : float [W/(m2K)]
        Area-weighted radiative coefficient of all surfaces facing the
        inside of this thermal zone (OuterWalls, Windows, InnerWalls, ...).
    alpha_rad_outer_mean : float [W/(m2K)]
        Area-weighted radiative coefficient of all surfaces facing the
        ambient (OuterWalls, Windows, ...).
    heat_load : [W]
        Static heat load of the thermal zone.
    facade_areas : list of floats [m2]
        List containing the area of each facade (with same tilt and
        orientation) this includes also roofs and ground floors and windows.
    n_outer : int
        Number of total facades with different combination of tilt and
        orientation, windows and outer walls
    n_rt : int
        Number of total facades with different combination of tilt and
        orientation, Rooftops
    tilt_facade : list of floats [degree]
        Tilt of facades against the horizontal.
    orientation_facade : list of floats [degree]
        Orientation of facades (Azimuth).
        0 - North
        90 - East
        180 - South
        270 - West

    """

    def __init__(self, thermal_zone, merge_windows, t_bt):
        """Constructor for TwoElement"""

        self.internal_id = random.random()

        self.thermal_zone = thermal_zone
        self.merge_windows = merge_windows
        self.t_bt = t_bt

        # Attributes of inner walls
        self.area_iw = 0.0

        # coefficient of heat transfer facing the inside of this thermal zone
        self.alpha_conv_inner_iw = 0.0
        self.alpha_rad_inner_iw = 0.0
        self.alpha_comb_inner_iw = 0.0
        # coefficient of heat transfer facing the adjacent thermal zone
        self.alpha_conv_outer_iw = 0.0
        self.alpha_rad_outer_iw = 0.0
        self.alpha_comb_outer_iw = 0.0

        # UA-Value
        self.ua_value_iw = 0.0

        # resistances for heat transfer facing the inside of this thermal zone
        self.r_conv_inner_iw = 0.0
        self.r_rad_inner_iw = 0.0
        self.r_comb_inner_iw = 0.0
        self.r_conv_outer_iw = 0.0
        self.r_rad_outer_iw = 0.0
        self.r_comb_outer_iw = 0.0

        # lumped resistance/capacity
        self.r1_iw = 0.0
        self.c1_iw = 0.0

        # Attributes for outer walls
        self.area_ow = 0.0

        # coefficient of heat transfer facing the inside of this thermal zone
        self.alpha_conv_inner_ow = 0.0
        self.alpha_rad_inner_ow = 0.0
        self.alpha_comb_inner_ow = 0.0

        # coefficient of heat transfer facing the ambient
        self.alpha_conv_outer_ow = 0.0
        self.alpha_rad_outer_ow = 0.0
        self.alpha_comb_outer_ow = 0.0

        # UA-Value
        self.ua_value_ow = 0.0

        # resistances for heat transfer facing the inside of this thermal zone
        self.r_conv_inner_ow = 0.0
        self.r_rad_inner_ow = 0.0
        self.r_comb_inner_ow = 0.0

        # resistances for heat transfer facing the ambient
        self.r_conv_outer_ow = 0.0
        self.r_rad_outer_ow = 0.0
        self.r_comb_outer_ow = 0.0

        # lumped resistances/capacity
        self.r1_ow = 0.0
        self.r_rest_ow = 0.0
        self.c1_ow = 0.0
        self.r_total_ow = 0.0

        # Optical properties
        self.ir_emissivity_outer_ow = 0.0
        self.ir_emissivity_inner_ow = 0.0
        self.solar_absorp_ow = 0.0

        # Additional attributes
        self.weightfactor_ow = []
        self.weightfactor_ground = 0.0
        self.outer_wall_areas = []

        # Attributes for GroundFloor
        self.area_gf = 0.0

        # coefficient of heat transfer facing the inside of this thermal zone
        self.alpha_conv_inner_gf = 0.0
        self.alpha_rad_inner_gf = 0.0
        self.alpha_comb_inner_gf = 0.0

        # UA-Value
        self.ua_value_gf = 0.0

        # resistances for heat transfer facing the inside of this thermal zone
        self.r_conv_inner_gf = 0.0
        self.r_rad_inner_gf = 0.0
        self.r_comb_inner_gf = 0.0

        # lumped resistances/capacity
        self.r1_gf = 0.0
        self.r_rest_gf = 0.0
        self.c1_gf = 0.0
        self.r_total_gf = 0.0

        # Optical properties
        self.ir_emissivity_inner_gf = 0.0

        # Additional attributes

        self.weightfactor_ground = 0.0

        # Attributes for rooftops
        self.area_rt = 0.0

        # coefficient of heat transfer facing the inside of this thermal zone
        self.alpha_conv_inner_rt = 0.0
        self.alpha_rad_inner_rt = 0.0
        self.alpha_comb_inner_rt = 0.0

        # coefficient of heat transfer facing the ambient
        self.alpha_conv_outer_rt = 0.0
        self.alpha_rad_outer_rt = 0.0
        self.alpha_comb_outer_rt = 0.0

        # UA-Value
        self.ua_value_rt = 0.0

        # resistances for heat transfer facing the inside of this thermal zone
        self.r_conv_inner_rt = 0.0
        self.r_rad_inner_rt = 0.0
        self.r_comb_inner_rt = 0.0

        # resistances for heat transfer facing the ambient
        self.r_conv_outer_rt = 0.0
        self.r_rad_outer_rt = 0.0
        self.r_comb_outer_rt = 0.0

        # lumped resistances/capacity
        self.r1_rt = 0.0
        self.r_rest_rt = 0.0
        self.c1_rt = 0.0
        self.r_total_rt = 0.0

        # Optical properties
        self.ir_emissivity_outer_rt = 0.0
        self.ir_emissivity_inner_rt = 0.0
        self.solar_absorp_rt = 0.0

        # Additional attributes
        self.weightfactor_rt = []
        self.weightfactor_win_rt = []
        self.rooftop_areas = []
        self.tilt_rt = []
        self.orientation_rt = []

        # TODO: check this value
        self.r_rad_rt_iw = 0.0

        # Attributes for windows
        self.area_win = 0.0

        # coefficient of heat transfer facing the inside of this thermal zone
        self.alpha_conv_inner_win = 0.0
        self.alpha_rad_inner_win = 0.0
        self.alpha_comb_inner_win = 0.0
        self.ratio_conv_rad_inner_win = 0.0

        # coefficient of heat transfer facing the ambient
        self.alpha_conv_outer_win = 0.0
        self.alpha_rad_outer_win = 0.0
        self.alpha_comb_outer_win = 0.0

        # UA-Value
        self.ua_value_win = 0.0
        self.u_value_win = 0.0

        # resistances for heat transfer facing the inside of this thermal zone
        self.r_conv_inner_win = 0.0
        self.r_rad_inner_win = 0.0
        self.r_comb_inner_win = 0.0

        # resistances for heat transfer facing the ambient
        self.r_conv_outer_win = 0.0
        self.r_rad_outer_win = 0.0
        self.r_comb_outer_win = 0.0

        # lumped resistances/capacity
        self.r1_win = 0.0

        # Optical properties
        self.ir_emissivity_win = 0.0
        self.ir_emissivity_inner_win = 0.0
        self.solar_absorp_win = 0.0

        # Additional attributes
        self.weightfactor_win = []
        self.window_areas = []
        self.transparent_areas = []
        self.g_sunblind = []
        self.weighted_g_value = 0.0

        # Misc values

        self.alpha_rad_inner_mean = 0.0
        self.alpha_rad_outer_mean = 0.0
        self.n_outer = 0
        self.n_rt = 0
        self.facade_areas = []
        self.tilt_facade = []
        self.orientation_facade = []
        self.heat_load = 0.0
        self.cool_load = 0.0

    def calc_attributes(self):
        """Calls all necessary function to calculate model attributes"""

        for out_wall in self.thermal_zone.outer_walls:
            out_wall.calc_equivalent_res()
            out_wall.calc_ua_value()
        for rt in self.thermal_zone.rooftops:
            rt.calc_equivalent_res()
            rt.calc_ua_value()
        for gf in self.thermal_zone.ground_floors:
            gf.calc_equivalent_res()
            gf.calc_ua_value()
        for win in self.thermal_zone.windows:
            win.calc_equivalent_res()
            win.calc_ua_value()
        for inner_wall in (self.thermal_zone.inner_walls +
                           self.thermal_zone.floors +
                           self.thermal_zone.ceilings):
            inner_wall.calc_equivalent_res()
            inner_wall.calc_ua_value()

        self.set_calc_default()
        if len(self.thermal_zone.outer_walls) < 1:
            warnings.warn("No walls are defined as outer walls for thermal " +
                          "zone " + self.thermal_zone.name + " in building " +
                          self.thermal_zone.parent.name +
                          ", please be careful with results. In addition " +
                          "this might lead to RunTimeErrors")
        else:
            self._sum_outer_wall_elements()
        if len(self.thermal_zone.inner_walls + self.thermal_zone.floors +
               self.thermal_zone.ceilings) < 1:
            warnings.warn('For thermal zone ' + self.thermal_zone.name +
                          ' in building ' + self.thermal_zone.parent.name +
                          ', no inner walls have been defined.')
        else:
            self._sum_inner_wall_elements()
            self._calc_inner_elements()
        if len(self.thermal_zone.windows) < 1:
            warnings.warn('For thermal zone ' + self.thermal_zone.name +
                          ' in building ' + self.thermal_zone.parent.name +
                          ', no windows have been defined.')
        else:
            self._sum_window_elements()
        if len(self.thermal_zone.ground_floors) < 1:
            warnings.warn('For thermal zone ' + self.thermal_zone.name +
                          ' in building ' + self.thermal_zone.parent.name +
                          ', no ground floors have been defined.')
        else:
            self._sum_ground_floor_elements()
            self._calc_ground_floor_elements()
        if len(self.thermal_zone.rooftops) < 1:
            warnings.warn('For thermal zone ' + self.thermal_zone.name +
                          ' in building ' + self.thermal_zone.parent.name +
                          ', no rooftops have been defined.')
        else:
            self._sum_rooftop_elements()
            self._calc_rooftop_elements()
        if len(self.thermal_zone.outer_walls) >= 1 or \
           len(self.thermal_zone.windows) >= 1:
            self._calc_outer_elements()
            self._calc_wf()
            self._calc_mean_values()
        self._calc_number_of_elements()
        self._fill_zone_lists()
        self._calc_heat_load()

        return True

    @staticmethod
    def _calc_parallel_connection(element_list, omega):
        """Parallel connection of walls according to VDI 6007

        Calculates the parallel connection of wall elements according to VDI
        6007, resulting in R1 and C1 (equation 23, 24).

        Parameters
        ----------
        element_list : list
            List of inner or outer walls
        omega : float
            VDI 6007 frequency

        Returns
        ----------
        r1 : float [K/W]
            VDI 6007 resistance for all inner or outer walls
        c1 : float [K/W]
            VDI 6007 capacity all for inner or outer walls
        """

        for wall_count in range(len(element_list) - 1):

            if wall_count == 0:

                r1 = (element_list[wall_count].r1 *
                      element_list[wall_count].c1 ** 2 +
                      element_list[wall_count + 1].r1 *
                      element_list[wall_count + 1].c1 ** 2 + omega ** 2 *
                      element_list[wall_count].r1 *
                      element_list[wall_count + 1].r1 *
                      (element_list[wall_count].r1 +
                       element_list[wall_count + 1].r1) *
                      element_list[wall_count].c1 ** 2 *
                      element_list[wall_count + 1].c1 ** 2) / \
                     ((element_list[wall_count].c1 +
                       element_list[wall_count + 1].c1) ** 2 + omega ** 2 *
                      (element_list[wall_count].r1 +
                       element_list[wall_count + 1].r1) ** 2 *
                      element_list[wall_count].c1 ** 2 *
                      element_list[wall_count + 1].c1 ** 2)

                c1 = ((element_list[wall_count].c1 +
                       element_list[wall_count + 1].c1) ** 2 + omega ** 2 *
                      (element_list[wall_count].r1 +
                       element_list[wall_count + 1].r1) ** 2 *
                      element_list[wall_count].c1 ** 2 *
                      element_list[wall_count + 1].c1 ** 2) / \
                     (element_list[wall_count].c1 +
                      element_list[wall_count + 1].c1 + omega ** 2 *
                      (element_list[wall_count].r1 ** 2 *
                       element_list[wall_count].c1 +
                       element_list[wall_count + 1].r1 ** 2 *
                       element_list[wall_count + 1].c1) *
                      element_list[wall_count].c1 *
                      element_list[wall_count + 1].c1)
            else:
                r1x = r1
                c1x = c1
                r1 = (r1x * c1x ** 2 + element_list[wall_count + 1].r1 *
                      element_list[wall_count + 1].c1 ** 2 +
                      omega ** 2 * r1x * element_list[wall_count + 1].r1 *
                      (r1x + element_list[wall_count + 1].r1) *
                      c1x ** 2 * element_list[wall_count + 1].c1 ** 2) / \
                     ((c1x + element_list[wall_count + 1].c1) ** 2 +
                      omega ** 2 * (
                          r1x + element_list[wall_count + 1].r1) ** 2 *
                      c1x ** 2 * element_list[wall_count + 1].c1 ** 2)

                c1 = ((c1x + element_list[
                    wall_count + 1].c1) ** 2 + omega ** 2 *
                    (r1x + element_list[wall_count + 1].r1) ** 2 * c1x ** 2 *
                    element_list[wall_count + 1].c1 ** 2) / \
                    (c1x + element_list[wall_count + 1].c1 + omega ** 2 *
                     (r1x ** 2 * c1x + element_list[wall_count + 1].r1 **
                      2 * element_list[wall_count + 1].c1) * c1x *
                     element_list[wall_count + 1].c1)
        return r1, c1

    def _sum_outer_wall_elements(self):
        """Sum attributes for outer wall elements

        This function sums and computes the area-weighted values,
        where necessary  for coefficients of heat
        transfer, resistances, areas and UA-Values.

        For ThreeElement model it treats rooftops and outer walls
        as one kind of wall type.

        """

        self.area_ow = \
            (sum(out_wall.area for out_wall in
                 self.thermal_zone.outer_walls))

        self.ua_value_ow = \
            (sum(out_wall.ua_value for out_wall in
                 self.thermal_zone.outer_walls))

        self.r_total_ow = 1 / self.ua_value_ow

        # values facing the inside of the thermal zone

        self.r_conv_inner_ow = (1 /
                                (sum(1 / out_wall.r_inner_conv for out_wall in
                                     self.thermal_zone.outer_walls)))

        self.r_rad_inner_ow = (1 /
                               (sum(1 / out_wall.r_inner_rad for out_wall in
                                    self.thermal_zone.outer_walls)))

        self.r_comb_inner_ow = (1 /
                                (sum(1 / out_wall.r_inner_comb for out_wall in
                                     self.thermal_zone.outer_walls)))

        self.ir_emissivity_inner_ow = (
            (sum(out_wall.layer[0].material.ir_emissivity * out_wall.area for
                 out_wall in self.thermal_zone.outer_walls)) / self.area_ow)

        self.alpha_conv_inner_ow = (
            1 / (self.r_conv_inner_ow * self.area_ow))
        self.alpha_rad_inner_ow = (
            1 / (self.r_rad_inner_ow * self.area_ow))
        self.alpha_comb_inner_ow = (
            1 / (self.r_comb_inner_ow * self.area_ow))

        # values facing the ambient
        # ground floor does not have any coefficients on ambient side

        self.r_conv_outer_ow = (1 /
                                (sum(1 / out_wall.r_outer_conv for out_wall in
                                     self.thermal_zone.outer_walls)))
        self.r_rad_outer_ow = (1 /
                               (sum(1 / out_wall.r_outer_rad for out_wall in
                                    self.thermal_zone.outer_walls)))
        self.r_comb_outer_ow = (1 /
                                (sum(1 / out_wall.r_outer_comb for out_wall in
                                     self.thermal_zone.outer_walls)))

        self.ir_emissivity_outer_ow = (
            (sum(out_wall.layer[
                -1].material.ir_emissivity * out_wall.area
                for
                out_wall in
                self.thermal_zone.outer_walls))) / self.area_ow

        self.solar_absorp_ow = (
            (sum(out_wall.layer[
                -1].material.solar_absorp * out_wall.area
                for
                out_wall in
                self.thermal_zone.outer_walls))) / self.area_ow

        self.alpha_conv_outer_ow = (
            1 / (self.r_conv_outer_ow * self.area_ow))
        self.alpha_rad_outer_ow = (
            1 / (self.r_rad_outer_ow * self.area_ow))
        self.alpha_comb_outer_ow = (
            1 / (self.r_comb_outer_ow * self.area_ow))

    def _sum_ground_floor_elements(self):
        """Sum attributes for ground floor elements

        This function sums and computes the area-weighted values,
        where necessary (the class doc string) for coefficients of heat
        transfer, resistances, areas and UA-Values.

        """

        self.area_gf = sum(ground.area for ground in
                           self.thermal_zone.ground_floors)

        self.ua_value_gf = \
            (sum(ground.ua_value for ground in
                 self.thermal_zone.ground_floors))

        self.r_total_gf = 1 / self.ua_value_gf

        # values facing the inside of the thermal zone

        self.r_conv_inner_gf = (1 /
                                sum(1 / ground.r_inner_conv for ground in
                                    self.thermal_zone.ground_floors))

        self.r_rad_inner_gf = (1 /
                               sum(1 / ground.r_inner_rad for ground in
                                   self.thermal_zone.ground_floors))

        self.r_comb_inner_gf = (1 /
                                sum(1 / ground.r_inner_comb for ground in
                                    self.thermal_zone.ground_floors))

        self.ir_emissivity_inner_gf = sum(
            ground.layer[0].material.ir_emissivity * ground.area for ground
            in self.thermal_zone.ground_floors) / self.area_gf

        self.alpha_conv_inner_gf = (
            1 / (self.r_conv_inner_gf * self.area_gf))
        self.alpha_rad_inner_gf = (
            1 / (self.r_rad_inner_gf * self.area_gf))
        self.alpha_comb_inner_gf = (
            1 / (self.r_comb_inner_gf * self.area_gf))

    def _sum_rooftop_elements(self):
        """Sum attributes for rooftop elements

        This function sums and computes the area-weighted values,
        where necessary  for coefficients of heat
        transfer, resistances, areas and UA-Values.

        For ThreeElement model it treats rooftops and outer walls
        as one kind of wall type.

        """

        self.area_rt = sum(roof.area for roof in
                           self.thermal_zone.rooftops)

        self.ua_value_rt = sum(roof.ua_value for roof in
                               self.thermal_zone.rooftops)

        self.r_total_rt = 1 / self.ua_value_rt

        # values facing the inside of the thermal zone

        self.r_conv_inner_rt = (1 / sum(1 / roof.r_inner_conv for roof in
                                        self.thermal_zone.rooftops))

        self.r_rad_inner_rt = (1 / sum(1 / roof.r_inner_rad for roof in
                                       self.thermal_zone.rooftops))

        self.r_comb_inner_rt = (1 / sum(1 / roof.r_inner_comb for roof in
                                        self.thermal_zone.rooftops))

        self.ir_emissivity_inner_rt = sum(
            roof.layer[0].material.ir_emissivity * roof.area for
            roof in self.thermal_zone.rooftops) / self.area_rt

        self.alpha_conv_inner_rt = (
            1 / (self.r_conv_inner_rt * self.area_rt))
        self.alpha_rad_inner_rt = (
            1 / (self.r_rad_inner_rt * self.area_rt))
        self.alpha_comb_inner_rt = (
            1 / (self.r_comb_inner_rt * self.area_rt))

        # values facing the ambient
        # ground floor does not have any coefficients on ambient side

        self.r_conv_outer_rt = (1 / sum(1 / roof.r_outer_conv for roof in
                                        self.thermal_zone.rooftops))
        self.r_rad_outer_rt = (1 / sum(1 / roof.r_outer_rad for roof in
                                       self.thermal_zone.rooftops))
        self.r_comb_outer_rt = (1 / sum(1 / roof.r_outer_comb for roof in
                                        self.thermal_zone.rooftops))

        self.ir_emissivity_outer_rt = sum(
            roof.layer[-1].material.ir_emissivity * roof.area for
            roof in self.thermal_zone.rooftops) / self.area_rt

        self.solar_absorp_rt = sum(
            roof.layer[-1].material.solar_absorp * roof.area for
            roof in self.thermal_zone.rooftops) / self.area_rt

        self.alpha_conv_outer_rt = (
            1 / (self.r_conv_outer_rt * self.area_rt))
        self.alpha_rad_outer_rt = (
            1 / (self.r_rad_outer_rt * self.area_rt))
        self.alpha_comb_outer_rt = (
            1 / (self.r_comb_outer_rt * self.area_rt))

    def _sum_inner_wall_elements(self):
        """Sum attributes for interior elements

        This function sums and computes the area-weighted values,
        where necessary (the class doc string) for coefficients of heat
        transfer, resistances, areas and UA-Values.

        It treats all inner walls identical.

        Function is identical for TwoElement, ThreeElement and FourElement.

        Calculation of adjacent thermal zones and thus these attributes are
        currently not supported.

        """
        self.area_iw = \
            (sum(in_wall.area for in_wall in
                 self.thermal_zone.inner_walls)
             + sum(floor.area for floor in
                   self.thermal_zone.floors)
             + sum(ceiling.area for ceiling in
                   self.thermal_zone.ceilings))

        self.ua_value_iw = \
            (sum(in_wall.ua_value for in_wall in
                 self.thermal_zone.inner_walls)
             + sum(floor.ua_value for floor in
                   self.thermal_zone.floors)
             + sum(ceiling.ua_value for ceiling in
                   self.thermal_zone.ceilings))

        # values facing the inside of the thermal zone

        self.r_conv_inner_iw = (1 /
                                (sum(1 / in_wall.r_inner_conv for in_wall in
                                     self.thermal_zone.inner_walls)
                                 + sum(1 / floor.r_inner_conv for floor in
                                       self.thermal_zone.floors)
                                 + sum(1 / ceiling.r_inner_conv for ceiling in
                                       self.thermal_zone.ceilings)))

        self.r_rad_inner_iw = (1 /
                               (sum(1 / in_wall.r_inner_rad for in_wall in
                                    self.thermal_zone.inner_walls)
                                + sum(1 / floor.r_inner_rad for floor in
                                      self.thermal_zone.floors)
                                + sum(1 / ceiling.r_inner_rad for ceiling in
                                      self.thermal_zone.ceilings)))

        self.r_comb_inner_iw = (1 /
                                (sum(1 / in_wall.r_inner_comb for in_wall in
                                     self.thermal_zone.inner_walls)
                                 + sum(1 / floor.r_inner_comb for floor in
                                       self.thermal_zone.floors)
                                 + sum(1 / ceiling.r_inner_comb for ceiling in
                                       self.thermal_zone.ceilings)))

        self.ir_emissivity_inner_iw = (
            (sum(in_wall.layer[0].material.ir_emissivity * in_wall.area for
                 in_wall in self.thermal_zone.inner_walls)
             + sum(floor.layer[0].material.ir_emissivity * floor.area for
                   floor in self.thermal_zone.floors)
             + sum(ceiling.layer[0].material.ir_emissivity * ceiling.area for
                   ceiling in self.thermal_zone.ceilings)) / self.area_iw)

        self.alpha_conv_inner_iw = (
            1 / (self.r_conv_inner_iw * self.area_iw))
        self.alpha_rad_inner_iw = (
            1 / (self.r_rad_inner_iw * self.area_iw))
        self.alpha_comb_inner_iw = (
            1 / (self.r_comb_inner_iw * self.area_iw))

        # adjacent thermal zones are not supported!

    def _sum_window_elements(self):
        """Sum attributes for window elements

        This function sums and computes the area-weighted values,
        where necessary (the class doc string) for coefficients of heat
        transfer, resistances, areas and UA-Values.

        Function is identical for TwoElement, ThreeElement and FourElement.
        """

        self.area_win = sum(win.area for win in self.thermal_zone.windows)
        self.ua_value_win = sum(
            win.ua_value for win in self.thermal_zone.windows)
        self.u_value_win = self.ua_value_win / self.area_win

        # values facing the inside of the thermal zone

        self.r_conv_inner_win = (1 / (sum(1 / win.r_inner_conv for win in
                                          self.thermal_zone.windows)))

        self.r_rad_inner_win = (1 / (sum(1 / win.r_inner_rad for win in
                                         self.thermal_zone.windows)))

        self.r_comb_inner_win = (1 / (sum(1 / win.r_inner_comb for win in
                                          self.thermal_zone.windows)))

        self.ir_emissivity_inner_win = sum(
            win.layer[0].material.ir_emissivity * win.area for win in
            self.thermal_zone.windows) / self.area_win

        self.alpha_conv_inner_win = (
            1 / (self.r_conv_inner_win * self.area_win))
        self.alpha_rad_inner_win = (
            1 / (self.r_rad_inner_win * self.area_win))
        self.alpha_comb_inner_win = (
            1 / (self.r_comb_inner_win * self.area_win))
        self.ratio_conv_rad_inner_win = sum(win.a_conv * win.area for win in
                                            self.thermal_zone.windows) / \
            self.area_win

        # values facing the ambient

        self.r_conv_outer_win = (1 / (sum(1 / win.r_outer_conv for win in
                                          self.thermal_zone.windows)))

        self.r_rad_outer_win = (1 / (sum(1 / win.r_outer_rad for win in
                                         self.thermal_zone.windows)))

        self.r_comb_outer_win = (1 / (sum(1 / win.r_outer_comb for win in
                                          self.thermal_zone.windows)))

        self.ir_emissivity_win = sum(win.layer[-1].material.ir_emissivity
                                     * win.area for win in
                                     self.thermal_zone.windows) / self.area_win

        self.solar_absorp_win = sum(win.layer[-1].material.solar_absorp
                                    * win.area for win in
                                    self.thermal_zone.windows) / self.area_win

        self.weighted_g_value = sum(win.g_value * win.area for win in
                                    self.thermal_zone.windows) / self.area_win

        self.alpha_conv_outer_win = (
            1 / (self.r_conv_outer_win * self.area_win))
        self.alpha_rad_outer_win = (
            1 / (self.r_rad_outer_win * self.area_win))
        self.alpha_comb_outer_win = (
            1 / (self.r_comb_outer_win * self.area_win))

    def _calc_outer_elements(self):
        """Lumped parameter for outer wall elements

        Calculates all necessary parameters for outer walls. This includes
        OuterWalls and Rooftops.

        Attributes
        ----------
        omega : float [1/s]
            angular frequency with given time period.
        outer_walls : list
            List containing all TEASER Wall instances that are treated as same
            outer wall type. In case of TwoElement model OuterWalls, Rooftops
        """

        omega = 2 * math.pi / 86400 / self.t_bt

        outer_walls = (self.thermal_zone.outer_walls)

        if 0 < len(outer_walls) <= 1:
            # only one outer wall, no need to calculate chain matrix
            self.r1_ow = outer_walls[0].r1
            self.c1_ow = outer_walls[0].c1_korr
        elif len(outer_walls) > 1:
            # more than one outer wall, calculate chain matrix
            self.r1_ow, self.c1_ow = self._calc_parallel_connection(outer_walls,
                                                                    omega)
        else:
            warnings.warn("No walls are defined as outer walls, please be "
                          "careful with results. In addition this might lead "
                          "to RunTimeErrors")

        if self.merge_windows is False:
            try:

                if len(self.thermal_zone.windows) > 0:
                    self.r1_win = (1 / sum((1 / win.r1) for win in
                                           self.thermal_zone.windows))
                if len(self.thermal_zone.outer_walls) > 0:
                    conduction = (1 / sum((1 / element.r_conduc) for element in
                                  outer_walls))

                    self.r_rest_ow = (conduction - self.r1_ow)

            except RuntimeError:
                print("As no outer walls or no windows are defined lumped "
                      "parameter cannot be calculated")

        if self.merge_windows is True:

            try:
                if len(self.thermal_zone.windows) > 0 and  \
                   len(self.thermal_zone.outer_walls) > 0:
                    self.r1_win = 1 / sum(1 / (win.r1 / 6) for win in
                                          self.thermal_zone.windows)

                    self.r1_ow = 1 / (1 / self.r1_ow + 1 / self.r1_win)

                    self.r_total_ow = 1 / (self.ua_value_ow +
                                           self.ua_value_win)
                    self.r_rest_ow = (self.r_total_ow - self.r1_ow - 1 / (
                        ((1 / self.r_conv_inner_ow)
                         + (1 / self.r_conv_inner_win)
                         + (1 / self.r_rad_inner_ow)
                         + (1 / self.r_rad_inner_win)))) - 1 / (
                        self.alpha_comb_outer_ow * self.area_ow)

                self.ir_emissivity_inner_ow = (
                    (self.ir_emissivity_inner_ow * self.area_ow
                     + self.ir_emissivity_inner_win * self.area_win)
                    / (self.area_ow + self.area_win))

                self.ir_emissivity_outer_ow = (
                    (self.ir_emissivity_outer_ow * self.area_ow
                     + self.ir_emissivity_win * self.area_win)
                    / (self.area_ow + self.area_win))

                self.solar_absorp_ow = (
                    (self.solar_absorp_ow * self.area_ow
                     + self.solar_absorp_win * self.area_win)
                    / (self.area_ow + self.area_win))

            except RuntimeError:
                print("As no outer walls or no windows are defined lumped "
                      "parameter cannot be calculated")

    def _calc_ground_floor_elements(self):
        """Lumped parameter for ground floor elements

        Calculates lumped parameters for ground floors. No windows in ground
        floor allowed.

        Attributes
        ----------
        omega : float [1/s]
            angular frequency with given time period.
        """

        omega = 2 * math.pi / 86400 / self.t_bt

        if 0 < len(self.thermal_zone.ground_floors) <= 1:
            # only one outer wall, no need to calculate chain matrix
            self.r1_gf = self.thermal_zone.ground_floors[0].r1
            self.c1_gf = self.thermal_zone.ground_floors[0].c1_korr
        elif len(self.thermal_zone.ground_floors) > 1:
            # more than one outer wall, calculate chain matrix
            self.r1_gf, self.c1_gf = self._calc_parallel_connection(
                self.thermal_zone.ground_floors, omega)
        else:
            warnings.warn("No walls are defined as ground floors, please be "
                          "careful with results. In addition this might lead "
                          "to RunTimeErrors")
        try:
            conduction = (1 / sum((1 / element.r_conduc) for element in
                                  self.thermal_zone.ground_floors))

            self.r_rest_gf = (conduction - self.r1_gf)
        except RuntimeError:
            print("As no ground floors are defined lumped "
                  "parameter cannot be calculated")

    def _calc_rooftop_elements(self):
        """Lumped parameter for ground floor elements

        Calculates lumped parameters for rooftops. Windows are considered in
        outer wall calculation. This results in an error concerning the
        interior radiation distribution. But currently there is no other option.

        Attributes
        ----------
        omega : float [1/s]
            angular frequency with given time period.
        """

        omega = 2 * math.pi / 86400 / self.t_bt

        if 0 < len(self.thermal_zone.rooftops) <= 1:
            # only one outer wall, no need to calculate chain matrix
            self.r1_rt = self.thermal_zone.rooftops[0].r1
            self.c1_rt = self.thermal_zone.rooftops[0].c1_korr
        elif len(self.thermal_zone.rooftops) > 1:
            # more than one outer wall, calculate chain matrix
            self.r1_rt, self.c1_rt = self._calc_parallel_connection(
                self.thermal_zone.rooftops, omega)
        else:
            warnings.warn("No walls are defined as ground floors, please be "
                          "careful with results. In addition this might lead "
                          "to RunTimeErrors")
        try:
            conduction = (1 / sum((1 / element.r_conduc) for element in
                                  self.thermal_zone.rooftops))

            self.r_rest_rt = (conduction - self.r1_rt)
        except RuntimeError:
            print("As no rooftops are defined lumped "
                  "parameter cannot be calculated")

    def _calc_inner_elements(self):
        """Lumped parameter for outer wall elements

        Calculates all necessary parameters for inner walls. This includes
        InnerWalls, Ceilings and Floors.

        Attributes
        ----------
        omega : float [1/s]
            angular frequency with given time period.
        outer_walls : list
            List containing all TEASER Wall instances that are treated as same
            outer wall type. In case of TwoElement model OuterWalls,
            GroundFloors, Rooftops
        """

        omega = 2 * math.pi / 86400 / self.t_bt

        inner_walls = (self.thermal_zone.inner_walls +
                       self.thermal_zone.floors +
                       self.thermal_zone.ceilings)

        for in_wall in inner_walls:
            in_wall.calc_equivalent_res()
            in_wall.calc_ua_value()

        if 0 < len(inner_walls) <= 1:
            # only one outer wall, no need to calculate chain matrix
            self.r1_iw = inner_walls[0].r1
            self.c1_iw = inner_walls[0].c1_korr
        elif len(inner_walls) > 1:
            # more than one outer wall, calculate chain matrix
            self.r1_iw, self.c1_iw = self._calc_parallel_connection(
                inner_walls,
                omega)
        else:
            warnings.warn("No walls are defined as outer walls, please be "
                          "careful with results. In addition this might lead "
                          "to RunTimeErrors")

    def _calc_wf(self):
        """Weightfactors for outer elements(walls, roof, ground floor, windows)

        Calculates the weightfactors of outer walls, rooftops, including
        ground and windows.

        """

        self.weightfactor_ground = 0.0

        if self.merge_windows is True:

            for wall in self.thermal_zone.outer_walls:
                wall.wf_out = wall.ua_value / (
                    self.ua_value_ow + self.ua_value_win)

            for win in self.thermal_zone.windows:
                win.wf_out = win.ua_value / (
                    self.ua_value_ow + self.ua_value_win)

            for rt in self.thermal_zone.rooftops:
                rt.wf_out = rt.ua_value / self.ua_value_rt

        elif self.merge_windows is False:

            for wall in self.thermal_zone.outer_walls:
                wall.wf_out = wall.ua_value / self.ua_value_ow

            for win in self.thermal_zone.windows:
                win.wf_out = win.ua_value / self.ua_value_win

            for rt in self.thermal_zone.rooftops:
                rt.wf_out = rt.ua_value / self.ua_value_rt

        else:
            raise ValueError("specify merge window method correctly")

    def _calc_mean_values(self):
        """Calculates mean values for inner and outer elements

        This function calculates mean values inside the thermal zone (e.g.
        the mean value for coefficient of radiative heat transfer between
        inner and outer walls
        """

        self.alpha_rad_inner_mean = (self.area_ow * self.alpha_rad_inner_ow +
                                     self.area_win * self.alpha_rad_inner_win +
                                     self.area_gf * self.alpha_rad_inner_gf +
                                     self.area_rt * self.alpha_rad_inner_rt +
                                     self.area_iw * self.alpha_rad_inner_iw) \
            / (self.area_ow + self.area_win +
               self.area_iw + self.area_gf +
               self.area_rt)
        self.alpha_rad_outer_mean = (self.area_ow * self.alpha_rad_outer_ow +
                                     self.area_rt * self.alpha_rad_outer_rt +
                                     self.area_win * self.alpha_rad_outer_win) \
            / (self.area_ow + self.area_rt +
               self.area_win)

    def _calc_number_of_elements(self):
        """Calculates the number of facade elements with different tilt/orient

        This function calculates the number of outer elements with a
        different combination of orientation and tilt, this includes the
        rooftops and ground floors.
        """

        outer_elements = (
            self.thermal_zone.outer_walls + self.thermal_zone.windows)

        tilt_orient = []
        for element in outer_elements:
            tilt_orient.append((element.orientation, element.tilt))
        self.n_outer = len(list(set(tilt_orient)))

        tilt_orient_rt = []
        for roof in self.thermal_zone.rooftops:
            tilt_orient_rt.append((roof.orientation, roof.tilt))
        self.n_rt = len(list(set(tilt_orient_rt)))

    def _fill_zone_lists(self):
        """Fills lists like weightfactors and tilt, orientation

        Fills the lists of a zone  according to orientation and tilt of the
        zone. Therefore it compares orientation and tilt of all outer
        elements and then creates lists for zone weightfactors, orientation,
        tilt, ares and sunblinds."""

        outer_elements = (
            self.thermal_zone.outer_walls +
            self.thermal_zone.windows)

        tilt_orient = []
        for element in outer_elements:
            tilt_orient.append((element.orientation, element.tilt))
        tilt_orient = list(set(tilt_orient))

        for i in tilt_orient:
            walls = self.thermal_zone.find_walls(i[0], i[1])
            wins = self.thermal_zone.find_wins(i[0], i[1])

            if self.merge_windows is True:
                self.facade_areas.append(sum([element.area for element in (
                    walls + wins)]))
            else:
                self.facade_areas.append(sum([element.area for element in (
                    walls)]))

            self.orientation_facade.append(i[0])
            self.tilt_facade.append(i[1])

            if not walls:
                self.weightfactor_ow.append(0.0)
                self.outer_wall_areas.append(0.0)
            else:
                self.weightfactor_ow.append(
                    sum([wall.wf_out for wall in walls]))
                self.outer_wall_areas.append(sum([wall.area for wall in
                                                  walls]))

            if not wins:
                self.weightfactor_win.append(0.0)
                self.g_sunblind.append(0.0)
                self.window_areas.append(0.0)
                self.transparent_areas.append(0.0)
            else:
                self.weightfactor_win.append(
                    sum([win.wf_out for win in wins]))
                self.g_sunblind.append(
                    sum([win.shading_g_total for win in wins]))

                if self.merge_windows is False:
                    self.window_areas.append(
                        sum([win.area for win in wins]))
                    self.transparent_areas.append(
                        sum([win.area for win in wins]))

                else:
                    self.window_areas.append(0)
                    self.transparent_areas.append(
                        sum([win.area for win in wins]))

        tilt_orient_rt = []
        for roof in self.thermal_zone.rooftops:
            tilt_orient_rt.append((roof.orientation, roof.tilt))
        tilt_orient_rt = list(set(tilt_orient_rt))

        for i in tilt_orient_rt:
            rts = self.thermal_zone.find_rts(i[0], i[1])

            self.orientation_rt.append(i[0])
            self.tilt_rt.append(i[1])
            self.weightfactor_win_rt.append(0)
            if not rts:
                self.weightfactor_rt.append(0.0)
                self.rooftop_areas.append(0.0)
            else:
                self.weightfactor_rt.append(
                    sum([rt.wf_out for rt in rts]))
                self.rooftop_areas.append(sum([rt.area for rt in rts]))

    def _calc_heat_load(self):
        """Static heat load calculation

        This function calculates the static heat load of the thermal zone by
        multiplying the UA-Value of the elements with the given Temperature
        difference of t_inside and t_outside. And takes heat losses through
        infiltration into account.

        Attributes
        ----------
        ua_value_ow_temp : float [W/(m2*K)]
            UA Value without GroundFloors
        ua_value_gf_temp : float [W/(m2*K)]
            UA Value of all GroundFloors
        """
        self.heat_load = 0.0

        ua_value_ow_temp = self.ua_value_rt + self.ua_value_ow
        self.heat_load = \
            ((((ua_value_ow_temp + self.ua_value_win) +
               self.thermal_zone.volume *
               self.thermal_zone.use_conditions.infiltration_rate * 1 / 3600 *
               self.thermal_zone.heat_capac_air *
               self.thermal_zone.density_air) * (self.thermal_zone.t_inside -
                                                 self.thermal_zone.t_outside))
             + (self.ua_value_gf * (self.thermal_zone.t_inside -
                                    self.thermal_zone.t_ground)))

    def set_calc_default(self):
        """sets default calculation parameters
        """

        # Attributes of inner walls
        self.area_iw = 0.0

        # coefficient of heat transfer facing the inside of this thermal zone
        self.alpha_conv_inner_iw = 0.0
        self.alpha_rad_inner_iw = 0.0
        self.alpha_comb_inner_iw = 0.0
        # coefficient of heat transfer facing the adjacent thermal zone
        self.alpha_conv_outer_iw = 0.0
        self.alpha_rad_outer_iw = 0.0
        self.alpha_comb_outer_iw = 0.0

        # UA-Value
        self.ua_value_iw = 0.0

        # resistances for heat transfer facing the inside of this thermal zone
        self.r_conv_inner_iw = 0.0
        self.r_rad_inner_iw = 0.0
        self.r_comb_inner_iw = 0.0
        self.r_conv_outer_iw = 0.0
        self.r_rad_outer_iw = 0.0
        self.r_comb_outer_iw = 0.0

        # lumped resistance/capacity
        self.r1_iw = 0.0
        self.c1_iw = 0.0

        # Attributes for outer walls
        self.area_ow = 0.0

        # coefficient of heat transfer facing the inside of this thermal zone
        self.alpha_conv_inner_ow = 0.0
        self.alpha_rad_inner_ow = 0.0
        self.alpha_comb_inner_ow = 0.0

        # coefficient of heat transfer facing the ambient
        self.alpha_conv_outer_ow = 0.0
        self.alpha_rad_outer_ow = 0.0
        self.alpha_comb_outer_ow = 0.0

        # UA-Value
        self.ua_value_ow = 0.0

        # resistances for heat transfer facing the inside of this thermal zone
        self.r_conv_inner_ow = 0.0
        self.r_rad_inner_ow = 0.0
        self.r_comb_inner_ow = 0.0

        # resistances for heat transfer facing the ambient
        self.r_conv_outer_ow = 0.0
        self.r_rad_outer_ow = 0.0
        self.r_comb_outer_ow = 0.0

        # lumped resistances/capacity
        self.r1_ow = 0.0
        self.r_rest_ow = 0.0
        self.c1_ow = 0.0
        self.r_total_ow = 0.0

        # Optical properties
        self.ir_emissivity_outer_ow = 0.0
        self.ir_emissivity_inner_ow = 0.0
        self.solar_absorp_ow = 0.0

        # Additional attributes
        self.weightfactor_ow = []
        self.weightfactor_ground = 0.0
        self.outer_wall_areas = []

        # Attributes for GroundFloor
        self.area_gf = 0.0

        # coefficient of heat transfer facing the inside of this thermal zone
        self.alpha_conv_inner_gf = 0.0
        self.alpha_rad_inner_gf = 0.0
        self.alpha_comb_inner_gf = 0.0

        # UA-Value
        self.ua_value_gf = 0.0

        # resistances for heat transfer facing the inside of this thermal zone
        self.r_conv_inner_gf = 0.0
        self.r_rad_inner_gf = 0.0
        self.r_comb_inner_gf = 0.0

        # lumped resistances/capacity
        self.r1_gf = 0.0
        self.r_rest_gf = 0.0
        self.c1_gf = 0.0
        self.r_total_gf = 0.0

        # Optical properties
        self.ir_emissivity_inner_gf = 0.0

        # Additional attributes

        self.weightfactor_ground = 0.0

        # Attributes for rooftops
        self.area_rt = 0.0

        # coefficient of heat transfer facing the inside of this thermal zone
        self.alpha_conv_inner_rt = 0.0
        self.alpha_rad_inner_rt = 0.0
        self.alpha_comb_inner_rt = 0.0

        # coefficient of heat transfer facing the ambient
        self.alpha_conv_outer_rt = 0.0
        self.alpha_rad_outer_rt = 0.0
        self.alpha_comb_outer_rt = 0.0

        # UA-Value
        self.ua_value_rt = 0.0

        # resistances for heat transfer facing the inside of this thermal zone
        self.r_conv_inner_rt = 0.0
        self.r_rad_inner_rt = 0.0
        self.r_comb_inner_rt = 0.0

        # resistances for heat transfer facing the ambient
        self.r_conv_outer_rt = 0.0
        self.r_rad_outer_rt = 0.0
        self.r_comb_outer_rt = 0.0

        # lumped resistances/capacity
        self.r1_rt = 0.0
        self.r_rest_rt = 0.0
        self.c1_rt = 0.0
        self.r_total_rt = 0.0

        # Optical properties
        self.ir_emissivity_outer_rt = 0.0
        self.ir_emissivity_inner_rt = 0.0
        self.solar_absorp_rt = 0.0

        # Additional attributes
        self.weightfactor_rt = []
        self.rooftop_areas = []
        self.tilt_rt = []
        self.orientation_rt = []

        # TODO: check this value
        self.r_rad_rt_iw = 0.0

        # Attributes for windows
        self.area_win = 0.0

        # coefficient of heat transfer facing the inside of this thermal zone
        self.alpha_conv_inner_win = 0.0
        self.alpha_rad_inner_win = 0.0
        self.alpha_comb_inner_win = 0.0
        self.ratio_conv_rad_inner_win = 0.0

        # coefficient of heat transfer facing the ambient
        self.alpha_conv_outer_win = 0.0
        self.alpha_rad_outer_win = 0.0
        self.alpha_comb_outer_win = 0.0

        # UA-Value
        self.ua_value_win = 0.0
        self.u_value_win = 0.0

        # resistances for heat transfer facing the inside of this thermal zone
        self.r_conv_inner_win = 0.0
        self.r_rad_inner_win = 0.0
        self.r_comb_inner_win = 0.0

        # resistances for heat transfer facing the ambient
        self.r_conv_outer_win = 0.0
        self.r_rad_outer_win = 0.0
        self.r_comb_outer_win = 0.0

        # lumped resistances/capacity
        self.r1_win = 0.0

        # Optical properties
        self.ir_emissivity_win = 0.0
        self.solar_absorp_win = 0.0

        # Additional attributes
        self.weightfactor_win = []
        self.window_areas = []
        self.transparent_areas = []
        self.g_sunblind = []
        self.weighted_g_value = 0.0

        # Misc values

        self.alpha_rad_inner_mean = 0.0
        self.n_outer = 0
        self.n_rt = 0
        self.facade_areas = []
        self.tilt_facade = []
        self.orientation_facade = []
        self.heat_load = 0.0
        self.cool_load = 0.0