LDD-05 · HVAC System (Overview)

To regenerate: hand the prompt below to Codex / ChatGPT with image generation enabled (or any gpt-image-1 / DALL-E 3 endpoint), save the result as site/diagrams/05-hvac-fpo.png, redeploy. Page picks it up automatically.

Recommended params: model gpt-image-1, aspect 16:9, size 1536 × 1024.

Prompt:

Architectural systems-visualization rendering of a 120' × 60' luxury pre-engineered metal building (PEMB) barndominium, shown as a longitudinal partial cutaway / sectional perspective looking east, with the west wall removed so the entire interior N-S length is visible. Wide-angle photoreal view, captured in cool late-morning ambient light. 16:9 aspect. No people in frame. The render reads as part architectural rendering, part exposed-systems diagram — the HVAC infrastructure is the subject.

Spatial hierarchy. The cutaway reveals four bays (30' each) running N to S from left to right of frame: north 30' = ILS zone, central 60' = gym (foreground) + living wing (behind the spine), south 30' = garage / workshop. Two floors are visible — ground floor and upper bedroom level. The PEMB structure is exposed in dark charcoal — primary frames, purlins, secondary framing.

Zone-by-zone HVAC infrastructure (the hero subject). Each zone shows its dedicated system, visibly distinct:

- Living wing (right-center of frame, behind the spine wall): A single ~14"-diameter pre-insulated round main trunk runs N-S high in the ceiling, centered ~12' off the spine. Five visible E-W primary branches drop perpendicular off the trunk, each ending in a discreet linear slot diffuser integrated into the ceiling plane. Smooth wye takeoffs, long-radius elbows, dark-bronze finish on the duct exterior so it reads as architectural rather than utility.

- Gym (center-left foreground): Two small commercial high-wall mini-split indoor units mounted on the west wall (matte white casings), and four low-profile dark-bronze destratification fans suspended from the gym ceiling structure at orderly intervals — small residential-commercial hybrids, NOT giant warehouse HVLS fans. The fans hang ~16' AFF, integrated into the three N-S ceiling infrastructure bands.

- Upstairs bedrooms (upper level, above the living wing): A separate ducted heat pump system — smaller trunk visible running through the upper-floor ceiling cavity, supplying bedroom branches.

- UCR / pajama lounge (upper level, above the gym): Radiant heat indication — visible hydronic supply lines coming up from the central manifold, a subtle reminder of the radiant + passive-cooling strategy.

- ILS (north 30' bay, left of frame): A single mini-split indoor unit visible on the north wall, plus an outdoor condenser stub visible through the north envelope.

- Workshop (south 30' bay, right of frame): A single mini-split indoor unit visible high on the south wall.

- LOW (above the workshop): A capped line-set stub-out visible at the upper south wall, marked as Phase 1 rough-in only.

Central mechanical room. Just visible at the south end ground level, behind a discreet door, glimpses of a hydronic manifold cluster + heat pump indoor coil + ERV unit. Not the focus, but present as the system origin.

ERV. A small dark-bronze ERV unit mounted high on the south wall above the mech room, with two discreet supply/exhaust penetrations through the IMP envelope. Restrained, not flashy.

Surrounding architecture. Polished light-warm hardwood floors visible in the gym + living + bedroom zones. Light-warm concrete sealed-slab floors in the ILS, workshop, and garage zones. Matte medium-warm-gray IMP envelope panels visible where the cutaway exposes the perimeter. Dark charcoal PEMB structure throughout.

Lighting mood. Cool, even, late-morning ambient — soft and diagnostic, like a high-quality architectural section rendering. NOT golden-hour. The mood is "systems clarity" — every duct, fan, and unit reads cleanly without dramatic shadow. Subtle warm glow from a few interior fixtures in the living wing as accent.

Material palette. Dark charcoal PEMB steel and exposed ceiling structure, dark-bronze ducts and ERV and destratification fans, matte white commercial mini-split casings, restrained dark-bronze trim throughout, light-warm hardwood / concrete floor planes, medium-warm-gray IMP envelope cuts. No bright colors. No yellow/black hazard striping. No bright-blue or red ductwork.

What this is NOT (critical). Do NOT render as: an HVAC catalog illustration, a residential ductwork-101 textbook diagram, a mechanical-room photograph, a commercial-building MEP coordination snapshot, or an explanatory exploded axonometric with floating arrows and labels. NO floating arrows or text labels. NO bright-yellow sheet metal. NO bright-blue or red ductwork colors. NO commercial-warehouse HVLS fans (the destratification fans must be small + dark + visually quiet). NO uniform suspended ceiling tile. NO drop ceiling at all. NO triangulated arena trusses.

Style direction. Professional architectural systems visualization, photoreal, evenly exposed. Reads as part long-section perspective, part educational systems diagram — but no diagram annotations in frame. Neutral camera at slight elevation (~7'-8' to see across both floors), perpendicular to the cutaway plane, wide angle equivalent to ~24mm full-frame. Sharp focus throughout, no shallow DOF. Should feel like an architecture-and-engineering-magazine spread on "how this house breathes," not an MEP coordination drawing.