Methodology
A single standardized exterior CFD methodology, applied to every facility in the cohort.
Scope
Each model examines the exterior airflow and thermal behavior around the building under representative wind and operating conditions: rooftop heat-rejection discharge, generator stack exhaust during emergency operation, and the resulting plume trajectories, recirculation patterns, and intake exposure. Interior thermal management and any aspect of as-built operational performance are out of scope.
Domain and geometry
- Cylindrical far-field domain, approximately 1 km radius.
- Ceiling height approximately 10 building heights above grade.
- Coordinate system: +Y true north, +Z up.
- Geometry sourced from public materials only — floor plans, satellite imagery, equipment counts. No proprietary drawings are used.
- Neighboring buildings within roughly 3 building heights are included as obstructions.
Atmospheric boundary conditions
- Inlet: logarithmic atmospheric boundary-layer velocity profile, reference height 10 m, von Kármán constant 0.4.
- Side walls: symmetry. Upper boundary: slip. Outlet: 0 Pa gauge pressure.
- Low-wind cases reconfigure the inlet and outlet as pressure boundaries.
- Ambient conditions: ASHRAE 0.4% cooling design values from the nearest reference station.
Heat sources
Rooftop units are modeled with paired mass-flow inlet and velocity outlet boundaries; discharge temperature is set by an intake-temperature-dependent thermal load, with optional derate tables. Generator stacks use manufacturer-typical exhaust temperatures and mass flows. Where equipment specifications are unavailable, industry mid-range values are applied and reported with a sensitivity note.
Solver and mesh
- Software: Siemens STAR-CCM+.
- Solver: segregated, steady-state RANS.
- Turbulence: realizable k-ε baseline; k-ω SST for low-wind, buoyancy-driven cases.
- Air: ideal gas (incompressible formulation) with polynomial-in-temperature specific heat and Sutherland's law viscosity.
- Mesh: polyhedral throughout — 48 ft base size in the far field, 16 ft base in the rooftop zone, and 2-inch local refinement at generator stack outlets.
- Grid-independence studies confirm mesh adequacy.
Outputs
Per-building deliverables comprise one headline visualization, three to four supporting visualizations across wind cases, and a one-paragraph summary. Quantitative outputs — chiller-inlet temperatures, generator re-ingestion temperatures, and recirculation values — are shared with the owner, developer, or design team of record on request.
Limitations
Exterior CFD built on public-source inputs is a screening-level analysis. Results indicate qualitative tendencies and relative comparisons across cases, not certified absolute performance. They represent idealized exterior conditions and do not represent the actual as-built performance of any facility.
Disclosure. This is independent research conducted by Resolved Analytics without engagement, sponsorship, or input from any firm or building owner. All inputs are derived from cited public sources; no proprietary drawings, specifications, or operational data are used. Facilities are described by type and configuration only and are not identified. Results represent idealized exterior conditions and do not represent the actual as-built performance of any facility. No claims are made regarding life-safety, code compliance, or operational performance. This material is not engineering services rendered to any party.