23. The system of claim 19 , wherein determining the one or more mass volumes comprises partitioning the one or more mass volumes into core mass volumes and perimeter mass volumes based on a specified distance between a perimeter of the core mass volume and a perimeter of a corresponding one of the one or more mass volumes.
19. A system comprising: one or more computers operable to perform operations comprising: receiving a conceptual representation of a building including one or more user-defined floor levels and multiple surfaces defining geometrical volumetric spaces; and responsive to a request to generate an analytical energy model, automatically generating the analytical energy model by: deriving geometric information from the conceptual representation; based on the geometric information, defining one or more mass volumes; algorithmically assigning one or more surface types to mass volume surfaces based, at least in part, on surface type definitions, a number of space adjacencies and the geometric information, associated with a corresponding mass volume surface, the surface type definitions specifying a material construction of a corresponding surface type; defining one or more thermal mass zones based on the determined one or more mass volumes and a corresponding number of user-defined floor levels; deriving, using a model generator, thermal properties of the one or more thermal mass zones; wherein the deriving is based on the geometrical columetric spaces, the one or more surface types assigned to the mass volume surfaces, and corresponding material construction; and combining the defined one or more thermal mass zones, the derived thermal properties, and predefined analytical energy model parameters to generate the analytical energy model.