| name | openfdd-ecm-engineering |
| description | Use when migrating or changing generic ECM math in open_fdd.ecm_engineering, publishing PyPI ECM workbook exports, or Compare honesty (FITTED vs industry). Triggers on: ECM, fan affinity, scheduling bins, full-parity workbook, Industry_Screening, BUG-ECM-018, BUG-ECM-019, sat_reset, open-fdd PyPI wheel. |
ECM engineering
Canonical generic math: open_fdd.ecm_engineering (PyPI).
EnergyPlus IDF surgery stays out of openfdd-mcp; patch/sim via EnergyPlus-MCP / WattLab runner.
vibe freeze (2026-07-30+): do not polish vibe19/vibe20 tips as the product path.
Ship spreadsheet + honesty through PyPI → open-fdd. See
docs/ecm/ENGINEER_UPSELL_BRIEF.md and docs/ecm/OPENFDD_AGENT_ECM_HANDOFF.md.
Golden example (Liberty dual-AHU)
Packaged workbook:
open_fdd/ecm_engineering/examples/liberty_dual_ahu/ECM_FULL_PARITY.xlsx
Characterization twin (test machine): runs/geo_b100_dual_ahu_shape_ops11.
Rules:
- Spreadsheet = 2nd set of eyes on E+ (industry method), not a rubber stamp.
- Never label reverse-solved FLH as independent BALLPARK (BUG-ECM-018 → FITTED).
- Dual-AHU
sat_reset must preserve winter dump + raise cool DAT on both AHUs
(BUG-ECM-019 — fixed +122 MWh vs broken flat-14°C −7 MWh).
- Opt-start industry = cut run hours + warmup/cooldown OAD 0% / full recirculation.
Migration pattern
inventory → golden/characterize → implement/confirm in Open-FDD
→ parity → switch adapter → delete twin → regression → docs → PyPI bump
Already delegated (do not re-port)
fan_affinity, schedule_reduction, outside_air_sensible, kw_per_ton_improvement,
boiler_efficiency_improvement, scheduling_fan/cooling/heating_bins.
Keepers: playground vibe_code_apps_20/docs/OPENFDD_ECM_TWINS.md (historical).
Result contracts
Return enough detail (summary, bins, assumptions, warnings, provenance,
fitted vs industry status) so adapters do not recompute formulas and UI
never green-checks fitted exact matches as independent validation.
