Unit-level data for MF/SFA buildings

[joseph-robertson]

Moved from: https://trello.com/c/Sgeu6Q7u/96-unit-level-data-for-mf-sfa-buildings.

ResStock currently has a number of building-level options that are mapped to dwelling unit (eg, stories, # of units, infiltration), we instead want to update:

• ResStockArguments to directly populate unit-level options (chose this for now)
• TSVs (do we eventually want to do this?)
  • Geometry Attic/Foundation Type
  • Infiltration
  • Geometry Stories
  • Ducts (leakage for units not adjacent to foundation space)
  • ?

[joseph-robertson]

For infiltration, we see adjusted ACH50 values as high as ~106 (multifamily, 67 units, 3 stories, sampled 50 ACH50). Although, as you can see in the plot below, the distributions across building types are generally similar.

[afontani]

For infiltration, the action would be to assign the ACH 50 value to the unit and scale it based on the amount of the area to the outside environment.

[joseph-robertson]

Here are the results when we set the air leakage type to "unit total" instead of "unit exterior only" (along w/ commenting out "Infiltration adjustment for SFA/MF units" in ResStockArguments).

[aspeake]

For infiltration, the action would be to assign the ACH 50 value to the unit and scale it based on the amount of the area to the outside environment.

That is supposed to be what's happening here:

resstock/measures/ResStockArguments/measure.rb

Lines 665 to 698 in 8500b4b

	# Infiltration adjustment for SFA/MF units
	# Calculate exposed wall area ratio for the unit (unit exposed wall area
	# divided by average unit exposed wall area)
	if (n_units_per_floor <= 2) || (n_units_per_floor == 4 && has_rear_units) # No middle unit(s)
	exposed_wall_area_ratio = 1.0 # all units have same exterior wall area
	else # Has middle unit(s)
	if has_rear_units
	n_end_units = 4 * n_floors
	n_mid_units = n_units - n_end_units
	n_bldg_fronts_backs = n_end_units + n_mid_units
	n_bldg_sides = n_end_units
	else
	n_end_units = 2 * n_floors
	n_mid_units = n_units - n_end_units
	n_bldg_fronts_backs = n_end_units * 2 + n_mid_units * 2
	n_bldg_sides = n_end_units
	end
	if has_rear_units
	n_unit_fronts_backs = 1
	else
	n_unit_fronts_backs = 2
	end
	if ['Middle'].include? horiz_location
	n_unit_sides = 0
	elsif ['Left', 'Right'].include? horiz_location
	n_unit_sides = 1
	end
	n_bldg_sides_equivalent = n_bldg_sides + n_bldg_fronts_backs * aspect_ratio
	n_unit_sides_equivalent = n_unit_sides + n_unit_fronts_backs * aspect_ratio
	exposed_wall_area_ratio = n_unit_sides_equivalent / (n_bldg_sides_equivalent / n_units)
	end
	# Apply adjustment to infiltration value
	args[:air_leakage_value] *= exposed_wall_area_ratio