Every EnerHabitat result is conditioned by the modelling assumptions below. This page is the canonical list: each entry states the assumption and the consequence it has for interpreting the outputs. The theory pages (1D, 2D) restate the subset relevant to each solver.
Scope
| A single opaque envelope component is simulated: no windows, no ventilation, no infiltration, no internal gains, no latent loads, no HVAC equipment model |
The energies quantify the component alone, per unit of its surface area; differences between results isolate the effect of the constructive system if the constructive system is the only change |
| The forcing is a synthetic monthly average day from an EPW file, iterated to a periodic regime |
Results characterise a typical day of the month, not an annual simulation nor any real weather sequence; extreme days are outside the scope unless an EPW is constructed |
In the air-conditioned mode the setpoint is constant and ideal (the adaptive neutrality temperature \(T_n\), or System2D.setpoint) |
No thermostat dynamics, schedules, equipment capacity or efficiency; demands are ideal sensible loads |
Materials and geometry
Materials are isotropic, homogeneous per region, with constant properties (k, rho, c) |
No temperature or moisture dependence; hygroscopic or phase-change materials are out of scope |
| Perfect thermal contact between layers (zero contact resistance) |
Real assemblies with air gaps or poor contact will transfer less heat than modelled |
| No moisture transport, condensation, rain wetting or internal heat generation |
Purely dry, sensible heat conduction |
| 1D: heat flows perpendicular to the component, per unit area |
Edge effects, thermal bridges and 2D/3D paths are not captured (use the 2D model for in-width heterogeneity) |
| 2D: the cross-section is invariant out of plane and the lateral cuts of the repeating cell lie on mirror-symmetry planes (adiabatic) |
Valid for the periodic HollowBlock/Slab patterns |
Surfaces and forcing
Prescribed film coefficients (NOM-008/020-ENER): \(h_o = 13\) fixed; walls \(h_i = 8.1\) W/(m²·K); roofs (tilt < 60°, EnergyPlus/ISO 6946 boundary) switch every time step between \(h_i = 9.4\) (upward flow) and \(6.6\) (downward flow) from the indoor-surface vs indoor-air temperatures |
No wind dependence; indoor coefficients are step-wise constants, not full convection correlations; configurable via config.ho/hi/hi_up/hi_down, and config.hi_flow = False restores a fixed \(h_i\) everywhere |
| Solar and long-wave loads enter through the sun–air temperature, with the empirical factor \(RF\) linear in tilt (3.9 → 0 °C between 0° and 90°) |
No shading, no urban context |
| The plane-of-array irradiance uses the isotropic-sky transposition with ground albedo 0.25 (pvlib defaults) |
Anisotropic sky models or site-specific albedo are not applied |
| The indoor air is a single well-mixed node of depth \(L_a=2.5\,m\) per unit area (free-running mode) |
No furniture or other-surface thermal mass; \(L_a\) is a volume-to-area ratio, not a room depth |
Cavities (2D, Fill.AIR)
| The air of each cavity is well mixed (one temperature per cavity) and radiatively non-participating, with constant properties |
Stratification inside a cavity is not resolved |
| One uniform \(h_c\) per cavity, from the correlations of Xamán (walls) or Hollands (roofs), evaluated with the mean face temperatures |
Local convection patterns are not resolved |
| Cavity surfaces are grey and diffuse, each emitting at its mean temperature, with uniform emissivity |
The radiosity (Gebhart) solution is exact within these assumptions; spectral or specular effects are not modelled |