The calculation of the total envelope resistance has been fixed

.github/workflows/python-package.yml

@@ -65,5 +65,5 @@ jobs:
  flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
  - name: Test with pytest
  run: |
- python -m pip install pytest-cov pytest-xdist[psutil]
- python -m pytest -n auto
+ python -m pip install pytest-cov
+ python -m pytest

pyumi/shoeboxer/shoebox.py

@@ -47,28 +47,40 @@ def __init__(self, *args, azimuth=180, **kwargs):
 
  @property
  def total_envelope_resistance(self):
- """Get the total envelope resistance [m2-K/W]."""
- u_factor = 0
+ """Get the total envelope resistance [m2-K/W].
+
+ Note:
+ The envelope is consisted of surfaces that have an outside boundary
+ condition different then `Adiabatic` or `Surface` or that participate in
+ the heat exchange with the exterior.
+
+ """
+ u_factor_times_area = 0
+ gross_area = 0
  for surface in self.getsurfaces():
- if surface.Surface_Type.lower() not in ["wall", "roof"]:
+ # loop over surfaces that have heat exchange
+ if surface.Outside_Boundary_Condition.lower() in ["adiabatic", "surface"]:
  continue
  construction = surface.get_referenced_object("Construction_Name")
- wall = OpaqueConstruction.from_epbunch(construction)
- wall_area = surface.area
+ surface_construction = OpaqueConstruction.from_epbunch(construction)
+ surface_area = surface.area
+ gross_area += surface_area
 
- window_area = 0
+ # for the surface, loop over subsurfaces (aka windows)
+ surface_window_area = 0
  window_u_factor = 0
- for subsurface in surface.subsurfaces:
+ for subsurface in surface.subsurfaces + surface.subsurfaces:
  construction = subsurface.get_referenced_object("Construction_Name")
  window = WindowConstruction.from_epbunch(construction)
- window_area = subsurface.area
- window_u_factor += window.u_factor
- wwr = window_area / wall_area
- u_factor += (
- wall.u_factor * wall_area * (1 - wwr)
- + window_u_factor * window_area * wwr
+ surface_window_area += subsurface.area
+ window_u_factor += window.u_factor * subsurface.area
+
+ # calculate the u_factor_times_area
+ u_factor_times_area += (
+ surface_construction.u_factor * (surface_area - surface_window_area)
+ + window_u_factor
  )
- return 1 / (u_factor / self.total_envelope_area)
+ return 1 / (u_factor_times_area / gross_area)
 
  @property
  def total_envelope_area(self):