Model/tests/domain
Khalim Conn-Kowlessar 7b30b464e5 feat(ventilation): credit MVHR (24a) heat recovery via PCDB Table 323 + 329
MVHR (24a) heat-recovery support, part 2: the mapper + cascade wiring.

Both source paths now resolve balanced whole-house MV with heat recovery
to the MVHR kind:
- gov-API: `_API_MECHANICAL_VENTILATION_TO_KIND` 4 → "MVHR" (was None /
  treated as natural — under-stated ventilation heat loss, over-rating).
- Elmhurst Summary: `_ELMHURST_MV_TYPE_TO_KIND` "Mechanical ventilation
  with heat recovery (MVHR)" → "MVHR" (was UnmappedElmhurstLabel, which
  blocked the whole Summary for MVHR dwellings).

cert_to_inputs resolves the in-use heat-recovery efficiency + SFP for an
MVHR cert (`_mvhr_system_values`): pick the PCDB Table 323 data point by
the lodged wet-room count (SAP 10.2 §2.6.4), multiply the raw efficiency
by the Table 329 ducts-inside-envelope in-use factor (0.90) and the raw
SFP by the per-duct-type factor (rigid 1.4), and feed:
- the §2.6.6 eq (2) effective-air-change credit (23c) → (24a)/(25)m;
- the (230a) fan electricity (in-use SFP × 1.22 × V), costed but NOT
  added to the Table 5a gains (its effect is in the efficiency).
An MVHR lodged with no PCDF index falls back to the SAP 10.2 Table 4g
default (raw efficiency 66% × 0.70, raw SFP 2.0 × 2.5).

Worksheet-proven on simulated case 49 (000565 semi + Vent Axia Sentinel
Kinetic B 500140 + gas combi → Elmhurst Current SAP 72): every MVHR line
matches Elmhurst exactly — (33) fabric heat loss 100.5923, (23c) in-use
efficiency 81.9% = 91 × 0.90, (25)m Jan 0.8571, (230a) fan electricity
415.9325, (231) total pumps/fans 501.9325. The residual SAP 71 vs 72 is
the known 000565-family space-heating-demand artifact (same -1/-2 seen on
cases 47/48), not the MVHR logic.

Corpus: within-0.5 72.6% -> 72.7%, MAE 0.788 -> 0.782, PE 3.6 -> 3.5.
The 3 gov-API MVHR certs: Flat 1 +6 -> 0 (Table 4g default path) and
12a Princes Gate +3 -> +1 (heat-recovery credit); Apartment 707 -4 -> -6
is a separate baseline under-rate (it under-rated as natural too — the
MVHR credit correctly adds ventilation loss per Elmhurst's method).
Ratcheted _MAX_SAP_MAE 0.79 -> 0.785, _MAX_PE_PER_M2_MAE 3.7 -> 3.6.

Note: pyright strict type gate not run locally (pyright not installed).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-23 19:45:37 +00:00
..
addresses standardist Address 2026-05-22 10:13:32 +00:00
billing refactor(billing): relocate Bill Derivation to domain/billing/ (cross-stage) 2026-06-03 17:19:23 +00:00
epc move overlas to its own thing 2026-06-18 10:04:14 +00:00
epc_prediction sap calculator variaince changes 2026-06-18 10:22:21 +00:00
fuel_rates feat(fuel-rates): FuelRates snapshot + repository foundation (ADR-0014) 2026-06-02 09:29:07 +00:00
magicplan handle 50 rows in new template file 2026-06-10 16:18:46 +00:00
modelling fix(climate): compute EPC CO2/PE on the postcode demand cascade (SAP 10.2 Appendix U p.124) 2026-06-18 14:15:34 +00:00
property move overlas to its own thing 2026-06-18 10:04:14 +00:00
property_baseline feat(baseline): sap_code_to_fuel normalizes via the calculator's own helper 2026-06-05 18:59:25 +00:00
sap10_calculator feat(ventilation): credit MVHR (24a) heat recovery via PCDB Table 323 + 329 2026-06-23 19:45:37 +00:00
tasks tests framework completed 2026-05-20 14:00:19 +00:00
__init__.py added postcode splitter rewrite to ddd 2026-05-19 16:35:09 +00:00
test_building_geometry.py feat(modelling): floor Recommendation Generator + ground-floor-area geometry 2026-06-03 09:12:29 +00:00
test_postcode.py tests framework completed 2026-05-20 14:00:19 +00:00