Worked cases · Miami
Three fan-coil wings and a lobby on one chiller, through a manifold
Guest rooms on the DOE Small Hotel rhythm — full at night, out by day — on two-pipe fan coils, a lobby on an outside-air unit that carries the latent plus a fan coil of its own, five receivers on one chiller.
Open the building in the appHarbour View is three wings of twelve guest rooms, each wing run as one fan-coil machine — a fan and a two-pipe coil at 1.2 m³/s, breathing the rooms' own air — and a lobby-and-restaurant on the outside-air unit (the lead, carrying the latent) plus a fan coil, all five receivers on the modular chiller through a water manifold. The rooms carry the Small Hotel occupancy profile: full at night, empty by day, the mall's opposite.
The fan coils found three control defects in one afternoon: a cycling machine's on-state is the landed scale when a ceiling held it above the floor (the wings had run a 5 % trickle all night, warm and wet); a cycled chiller's leaving water is the hour's mean, not its on-state; and an off valved coil reports zero flow, so a water-serving block with nothing to chill is off — which stopped the chiller cycling for a design flow going nowhere on 2 000 idle hours.
On Miami's year the building reads 323 MWh of cooling on 88.9 MWh of electricity; the lobby has 21 humid hours since its fan coils stopped drying what the outside-air unit already dries, and 9 unmet cooling hours on which the outside-air lead lands a few per cent short of the call and its fan coils are asked too little to start — nights on which the room ends 0.02–0.04 K over its 24 °C setpoint: the lead misses by a tenth of a kelvin or so at its top stage, and the 50–90 W left over, split between two fan coils, is under each one's idle threshold; the wings show 8 275 humid hours each — a two-pipe fan coil has no reheat, so no ceiling is declared, and the page says so.
What it reads on Miami
| Cooling / electricity | 323 MWh / 88.9 MWh |
| Lobby | 21 humid hours (274 before the moisture rule); 9 unmet cooling hours, the outside-air lead a few per cent short of the call and the room never above 24.0 °C |
| Wings | held, no unmet hour; 8 275 humid hours each (no reheat, no ceiling — declared) |
What it taught
- A manifold is several couplings on one port; the receivers' returns mix by flow, a shut valve counting as a fact about the header.
- A two-pipe fan coil holds temperature, not humidity; a ceiling on it only makes it over-cool the room.
- A chiller that sees no flow is off — a flow switch at a tenth of design flow made the pair oscillate across the one-hour lag.
The machines
- Fan-coil wing, 1.2 m³/s chilled water — open in the builder
- Outside-air unit with heat recovery, 0.45 m³/s — open in the builder
- Air-cooled chiller, 90 kW class — open in the builder
Sources
- DOE Commercial Prototype Building Models — Small Hotel (guest-room schedule)
- PVGIS TMY, Miami
Readings of the shipped model on the building's own PVGIS typical meteorological year; engineering estimates from catalog data and published correlations. The building runs on every plan, including Free, a few times a day.