Building

Weighted-average internal building temperature from canyon and roof surface temperatures, implementing Oleson et al. (2010, CLM Tech Note Ch. 4) Eqs. 4.37–4.38. The roof length L_roof in an infinite canyon (Eq. 4.38) and the unclamped building temperature T_iB_unclamped (Eq. 4.37) are both algebraic functions of the canyon geometry (H_canyon, H_W, W_roof) and the inner-surface temperatures of the shaded wall, sunlit wall, and roof. T_iB is the area-weighted average with the two walls contributing 2*H_canyon of effective length and the roof contributing L_roof. Migrated from UrbanCanopy.jl@9200edd4 src/roof_wall_road_snow_temperatures.jl:401 (`BuildingTemperature` @component). NOTE: the migration-tracker entry listed `blocking_gap: other:discretization-plan` citing line :1152, but that line belongs to `RoofWallHeatConduction` (a separate non-exported helper function). `BuildingTemperature` itself is a pure two-equation algebraic `@component` with no PDESystem or MOLFiniteDifference — this migration is unblocked.

Heating/cooling fluxes through the building floor for the urban canopy thermal column. Migrated from UrbanCanopy.jl@9200edd4 src/roof_wall_road_snow_temperatures.jl:638 (`HeatingCoolingFlux` @component). Implements Oleson et al. (2010, CLM Tech Note Ch. 4) Eqs. 4.51 and 4.52: the building uses HVAC to clamp the internal building temperature T_iB to the prescribed comfort window [T_iB_min, T_iB_max]. The combined floor flux F_combined is the Crank-Nicholson average of F_bottom_n (time n) and F_bottom_np1 (time n+1) per Eq. 4.53/4.54; if T_iB falls below T_iB_min the absolute value of F_combined is reported as the heating flux F_heat (Eq. 4.51); if T_iB rises above T_iB_max the absolute value is reported as the cooling flux F_cool (Eq. 4.52); inside the comfort window both F_heat and F_cool are zero (no HVAC demand). Parameterized as observed-only with three algebraic equations: F_combined, F_heat, F_cool are state variables; T_iB, T_iB_min, T_iB_max, F_bottom_n, F_bottom_np1 are inputs (parameters in standalone form).