MECHANICAL SYSTEM DESIGN
Systems, equipment and distribution
Deterministic Hexanta calculations from the native loads and the design criteria. Calculated, assumed and blocked values are labelled; no manufacturer rating is invented.
Results: Change run — criteria revision 3 — RECORDED (verified evidence, not re-run) · S3-P03C-CR003 (change on the P03A coordination candidate)
No equipment is selected (no selection register supplied)
No manufacturer-verified rating is held: every FCU, AHU, heat pump, pump and fan is NOT SELECTED. Pump and fan duties stay BLOCKED until fitting, terminal and plant-side losses are supplied.
Ventilation and air balance
Outdoor air
1,933.4 l/s
Calculated
General extract
1,621.4 l/s
Calculated
WC extract
312.0 l/s
Calculated
Ventilation rule values are SYNTHETIC (XX-TEST) until a licensed source is held.
AHU-01 — option A1 (scenario options, undecided)
SCENARIO OPTIONS — D-05a–g undecided; fan heat excluded; HR effectiveness is a regulatory-minimum scenario
Summer outdoor 32.1 °C db / 21 °C wb (IESVE Rev02 design weather (ASHRAE design weather database; heating 99.6 %, cooling 0.4 % monthly percentile)); room 24 °C, 50 % RH.
| Option | Cooling coil kW | Heating coil (winter) kW | Summer reheat kW | Warnings |
|---|---|---|---|---|
| A1 Neutral supply 24/21 C, room-neutral moisture, LTHW reheat (founder provisional temperatures) | 39.36 | 14.22 | 24.11 | condensation, frost_risk, reheat_required |
| A2 Neutral supply 24/21 C, drier supply absorbs room latent (FCUs sensible only) | 56.83 | 14.22 | 31.34 | condensation, frost_risk, reheat_required |
| A3 Cool supply 14 C summer (close to off-coil, minimal reheat), room-neutral moisture; 21 C winter | 39.36 | 14.22 | 0.63 | condensation, frost_risk, reheat_required |
Central plant (heat source and duties)
PROVISIONAL — base duties from native loads + AHU scenario options; pipe heat gains/losses, fan heat and distribution losses EXCLUDED (INPUT REQUIRED)
Heat source (proposed for coordination): four_pipe_ashp.
Cooling, basis A
100.3 kW
Room peaks + AHU coil
Cooling, basis B
88.4 kW
IESVE coincident + AHU (approx.)
Heating (AHU off in pre-heat)
33.1 kW
Margin (selected)
20 %
Assumed
PROVISIONAL — defaults, NOT engineer-selected. Room duties use ONE design peak per room: heating = the IESVE intermittent (boosted) plant load, which already includes the intermittent uplift over the steady-state load; cooling = room total (sensible + latent) at the room peak. The plant duty = the selected basis + the AHU coil of the selected AHU option (outdoor air counted once, on the AHU coil). The margin is applied ONCE, to that plant duty only; it is never applied to room loads, the AHU coil or the uplift separately.
| Heating plant | kW | Basis |
|---|---|---|
| Room design heating peaks (Σ, one per room) | 33.1 | IESVE boosted plant load |
| of which intermittent uplift (audit only) | 16.5 | already inside the design peaks — not added again |
| steady-state (audit only) | 16.6 | IESVE steady-state |
| AHU heating coil | 14.2 | AHU option A1 |
| Heating base duty | 47.3 | Σ room design heating peaks (intermittent uplift included) + AHU heating coil — preheat and AHU coincide (conservative) |
| Margin 20 % | 9.5 | applied once |
| Selected plant duty | 56.8 | plant_selection.margin_option = 20 % |
| Cooling plant | kW | Basis |
|---|---|---|
| Room design cooling peaks (Σ sensible + latent) | 60.9 | sensible 51.4 + latent 9.5 kW |
| Coincident building cooling (IESVE) | 49.1 | simultaneity 0.805 |
| AHU cooling coil (outdoor air, counted once) | 39.4 | AHU option A1 |
| Cooling base duty | 88.4 | IESVE coincident building cooling peak + AHU cooling coil — central plant (simultaneity from the simulation) |
| Margin 20 % | 17.7 | applied once |
| Selected plant duty | 106.1 | plant_selection.margin_option = 20 % |
Change the basis or the margin under Criteria → Plant selection; the change is recorded with its reason and re-run.
PROVISIONAL — scenarios for comparison; none is engineer-approved
| AHU option | Strategy | Base kW | +0 % | +10 % | +20 % | Summer reheat kW |
|---|---|---|---|---|---|---|
| A1 | Heating — AHU running during warm-up | 47.3 | 47.3 | 52.0 | 56.8 ● | 24.1 |
| A1 | Heating — AHU held off during warm-up | 33.1 | 33.1 | 36.4 | 39.7 | 24.1 |
| A1 | Cooling — coincident building peak | 88.4 | 88.4 | 97.2 | 106.1 ● | 24.1 |
| A1 | Cooling — sum of room peaks (non-coincident) | 100.3 | 100.3 | 110.3 | 120.3 | 24.1 |
| A2 | Heating — AHU running during warm-up | 47.3 | 47.3 | 52.0 | 56.8 | 31.3 |
| A2 | Heating — AHU held off during warm-up | 33.1 | 33.1 | 36.4 | 39.7 | 31.3 |
| A2 | Cooling — coincident building peak | 96.4 | 96.4 | 106.0 | 115.6 | 31.3 |
| A2 | Cooling — sum of room peaks (non-coincident) | 108.2 | 108.2 | 119.0 | 129.9 | 31.3 |
| A3 | Heating — AHU running during warm-up | 47.3 | 47.3 | 52.0 | 56.8 | 0.6 |
| A3 | Heating — AHU held off during warm-up | 33.1 | 33.1 | 36.4 | 39.7 | 0.6 |
| A3 | Cooling — coincident building peak | 65.1 | 65.1 | 71.6 | 78.1 | 0.6 |
| A3 | Cooling — sum of room peaks (non-coincident) | 76.9 | 76.9 | 84.6 | 92.3 | 0.6 |
● = the current selection (not approved). Each value = base × (1 + margin): the margin is applied once. Summer reheat runs with cooling in that AHU option (energy / Part L review).
Fan coil units — required duties
| FCU | Room | Cooling sens. W | Cooling total W | Heating W | Supply l/s | OA l/s | CHW l/s | LTHW l/s | Basis | Selection |
|---|---|---|---|---|---|---|---|---|---|---|
| FCU-GF-01 | Open-plan office zone 1 | 4,749 | 5,684 | 2,663 | 393.4 | 190.3 | 0.227 | 0.064 | Calculated | not selected |
| FCU-GF-02 | Open-plan office zone 1 | 4,749 | 5,684 | 2,663 | 393.4 | 190.3 | 0.227 | 0.064 | Calculated | not selected |
| FCU-GF-03 | Open-plan office zone 2 | 4,674 | 5,609 | 2,658 | 387.2 | 190.3 | 0.224 | 0.064 | Calculated | not selected |
| FCU-GF-04 | Open-plan office zone 2 | 4,674 | 5,609 | 2,658 | 387.2 | 190.3 | 0.224 | 0.064 | Calculated | not selected |
| FCU-GF-05 | Open-plan office zone 3 | 4,653 | 5,588 | 2,658 | 385.4 | 190.3 | 0.223 | 0.064 | Calculated | not selected |
| FCU-GF-06 | Open-plan office zone 3 | 4,653 | 5,588 | 2,658 | 385.4 | 190.3 | 0.223 | 0.064 | Calculated | not selected |
| FCU-GF-07 | Open-plan office zone 4 | 3,485 | 3,952 | 2,663 | 288.6 | 105.3 | 0.158 | 0.064 | Calculated | not selected |
| FCU-GF-08 | Open-plan office zone 4 | 3,485 | 3,952 | 2,663 | 288.6 | 105.3 | 0.158 | 0.064 | Calculated | not selected |
| FCU-GF-09 | Meeting room 1 | 4,830 | 6,150 | 2,074 | 400.1 | 250.8 | 0.245 | 0.050 | Calculated | not selected |
| FCU-GF-10 | Meeting room 2 | 4,584 | 5,904 | 1,616 | 379.7 | 250.8 | 0.235 | 0.039 | Calculated | not selected |
| FCU-GF-11 | Reception | 3,303 | 3,523 | 2,074 | 273.6 | 50.8 | 0.140 | 0.050 | Calculated | not selected |
| FCU-GF-12 | East lift lobby | 2,044 | 2,154 | 1,947 | 169.3 | 29.0 | 0.086 | 0.047 | Calculated | not selected |
a room's loads and outdoor air are divided equally between its FCUs (no per-facade split: IESVE models each zone as one room)
Distribution networks — sizing and index circuits
| Network | Medium | Design flow l/s | Sections | Index end | Route m | Friction lower bound Pa | Pressure |
|---|---|---|---|---|---|---|---|
| OA Outdoor air supply (AHU-01 to FCU inlet plenums) | air | 1,933.400 | 19 | FCU-GF-09 | 47.0 | 35 | lower bound (7 missing) |
| GEX General extract (rooms to AHU-01 heat recovery) | air | 1,621.400 | 13 | EG-GF-07 | 62.6 | 48 | lower bound (6 missing) |
| WCX WC extract (WCs to EF-01, discharge to atmosphere) | air | 312.000 | 5 | XG-GF-06 | 11.8 | 7 | lower bound (2 missing) |
| HW-CHW Four-pipe CHW and LTHW distribution (shared route; CHW omits LTHW-only branches) — CHW | water | 3.936 | 22 | FCU-GF-09 | 51.4 | 13,185 | lower bound (9 missing) |
| HW-LTHW Four-pipe CHW and LTHW distribution (shared route; CHW omits LTHW-only branches) — LTHW | water | 1.368 | 27 | FCU-GF-09 | 51.4 | 17,030 | lower bound (9 missing) |
| SD-01 FCU-GF-01 discharge to supply diffusers | air | 393.390 | 3 | SD-GF-01B | 4.4 | 4 | lower bound (1 missing) |
| SD-02 FCU-GF-02 discharge to supply diffusers | air | 393.390 | 3 | SD-GF-02B | 4.4 | 4 | lower bound (1 missing) |
| SD-03 FCU-GF-03 discharge to supply diffusers | air | 387.177 | 3 | SD-GF-03A | 4.4 | 4 | lower bound (1 missing) |
| SD-04 FCU-GF-04 discharge to supply diffusers | air | 387.177 | 3 | SD-GF-04A | 4.4 | 4 | lower bound (1 missing) |
| SD-05 FCU-GF-05 discharge to supply diffusers | air | 385.437 | 3 | SD-GF-05B | 4.4 | 4 | lower bound (1 missing) |
| SD-06 FCU-GF-06 discharge to supply diffusers | air | 385.437 | 3 | SD-GF-06B | 4.4 | 4 | lower bound (1 missing) |
| SD-07 FCU-GF-07 discharge to supply diffusers | air | 288.643 | 3 | SD-GF-07A | 4.4 | 2 | lower bound (1 missing) |
| SD-08 FCU-GF-08 discharge to supply diffusers | air | 288.643 | 3 | SD-GF-08A | 4.4 | 2 | lower bound (1 missing) |
| SD-09 FCU-GF-09 discharge to supply diffusers | air | 400.099 | 3 | SD-GF-09B | 4.2 | 4 | lower bound (1 missing) |
| SD-10 FCU-GF-10 discharge to supply diffusers | air | 379.722 | 3 | SD-GF-10B | 5.1 | 4 | lower bound (1 missing) |
| SD-11 FCU-GF-11 discharge to supply diffusers | air | 273.608 | 3 | SD-GF-11A | 3.0 | 2 | lower bound (1 missing) |
| SD-12 FCU-GF-12 discharge to supply diffusers | air | 169.317 | 1 | SD-GF-12A | 1.7 | 1 | lower bound (1 missing) |
Pumps and fans
| Tag | Description | Flow l/s | Pressure | Duty | Missing inputs |
|---|---|---|---|---|---|
| CHWP-01A/B | CHW secondary variable-speed pumps (duty/standby; PICV terminals) | 3.936 | BLOCKED — lower bound only | Blocked NOT CALCULATED | fitting ζ for every counted fitting (bends/tees); terminal device loss (coil + control valve + isolation, or grille/regulator); plant-side losses (heat pump/chiller, strainers, headers) |
| LTHWP-01A/B | LTHW secondary variable-speed pumps (duty/standby; PICV terminals) | 1.368 | BLOCKED — lower bound only | Blocked NOT CALCULATED | fitting ζ for every counted fitting (bends/tees); terminal device loss (coil + control valve + isolation, or grille/regulator); plant-side losses (heat pump/chiller, strainers, headers) |
| AHU-01 supply fan | AHU supply fan (external: OA ductwork to FCU plenums) | 1,933.400 | BLOCKED — lower bound only | Blocked NOT CALCULATED | fitting ζ for every counted fitting (bends/tees); terminal device loss (coil + control valve + isolation, or grille/regulator); AHU internal losses (filters, coils, heat recovery, attenuators) and intake/exhaust louvres |
| AHU-01 extract fan | AHU extract fan (external: general extract ductwork) | 1,621.400 | BLOCKED — lower bound only | Blocked NOT CALCULATED | fitting ζ for every counted fitting (bends/tees); terminal device loss (coil + control valve + isolation, or grille/regulator); AHU internal losses (filters, coils, heat recovery, attenuators) and intake/exhaust louvres |
| EF-01 | WC extract fan | 312.000 | BLOCKED — lower bound only | Blocked NOT CALCULATED | fitting ζ for every counted fitting (bends/tees); terminal device loss (coil + control valve + isolation, or grille/regulator); AHU internal losses (filters, coils, heat recovery, attenuators) and intake/exhaust louvres |
| FCU-GF-01 fan (external) | FCU fan external static: discharge plenum, branches and diffusers | 393.390 | BLOCKED — lower bound only | Blocked NOT CALCULATED | fitting ζ for every counted fitting; diffuser, plenum box and damper ΔP (manufacturer); FCU return-air path (ceiling plenum / grille) and filter ΔP |
| FCU-GF-02 fan (external) | FCU fan external static: discharge plenum, branches and diffusers | 393.390 | BLOCKED — lower bound only | Blocked NOT CALCULATED | fitting ζ for every counted fitting; diffuser, plenum box and damper ΔP (manufacturer); FCU return-air path (ceiling plenum / grille) and filter ΔP |
| FCU-GF-03 fan (external) | FCU fan external static: discharge plenum, branches and diffusers | 387.177 | BLOCKED — lower bound only | Blocked NOT CALCULATED | fitting ζ for every counted fitting; diffuser, plenum box and damper ΔP (manufacturer); FCU return-air path (ceiling plenum / grille) and filter ΔP |
| FCU-GF-04 fan (external) | FCU fan external static: discharge plenum, branches and diffusers | 387.177 | BLOCKED — lower bound only | Blocked NOT CALCULATED | fitting ζ for every counted fitting; diffuser, plenum box and damper ΔP (manufacturer); FCU return-air path (ceiling plenum / grille) and filter ΔP |
| FCU-GF-05 fan (external) | FCU fan external static: discharge plenum, branches and diffusers | 385.437 | BLOCKED — lower bound only | Blocked NOT CALCULATED | fitting ζ for every counted fitting; diffuser, plenum box and damper ΔP (manufacturer); FCU return-air path (ceiling plenum / grille) and filter ΔP |
| FCU-GF-06 fan (external) | FCU fan external static: discharge plenum, branches and diffusers | 385.437 | BLOCKED — lower bound only | Blocked NOT CALCULATED | fitting ζ for every counted fitting; diffuser, plenum box and damper ΔP (manufacturer); FCU return-air path (ceiling plenum / grille) and filter ΔP |
| FCU-GF-07 fan (external) | FCU fan external static: discharge plenum, branches and diffusers | 288.643 | BLOCKED — lower bound only | Blocked NOT CALCULATED | fitting ζ for every counted fitting; diffuser, plenum box and damper ΔP (manufacturer); FCU return-air path (ceiling plenum / grille) and filter ΔP |
| FCU-GF-08 fan (external) | FCU fan external static: discharge plenum, branches and diffusers | 288.643 | BLOCKED — lower bound only | Blocked NOT CALCULATED | fitting ζ for every counted fitting; diffuser, plenum box and damper ΔP (manufacturer); FCU return-air path (ceiling plenum / grille) and filter ΔP |
| FCU-GF-09 fan (external) | FCU fan external static: discharge plenum, branches and diffusers | 400.099 | BLOCKED — lower bound only | Blocked NOT CALCULATED | fitting ζ for every counted fitting; diffuser, plenum box and damper ΔP (manufacturer); FCU return-air path (ceiling plenum / grille) and filter ΔP |
| FCU-GF-10 fan (external) | FCU fan external static: discharge plenum, branches and diffusers | 379.722 | BLOCKED — lower bound only | Blocked NOT CALCULATED | fitting ζ for every counted fitting; diffuser, plenum box and damper ΔP (manufacturer); FCU return-air path (ceiling plenum / grille) and filter ΔP |
| FCU-GF-11 fan (external) | FCU fan external static: discharge plenum, branches and diffusers | 273.608 | BLOCKED — lower bound only | Blocked NOT CALCULATED | fitting ζ for every counted fitting; diffuser, plenum box and damper ΔP (manufacturer); FCU return-air path (ceiling plenum / grille) and filter ΔP |
| FCU-GF-12 fan (external) | FCU fan external static: discharge plenum, branches and diffusers | 169.317 | BLOCKED — lower bound only | Blocked NOT CALCULATED | fitting ζ for every counted fitting; diffuser, plenum box and damper ΔP (manufacturer); FCU return-air path (ceiling plenum / grille) and filter ΔP |
Quantities
Route lengths from the design model (plan route length; flow + return for water). Fittings, risers to terminals and drops are excluded: a lower bound for take-off, not a BOQ.
Ductwork
268.7 m
Pipework (flow + return)
446.4 m
GEX grille
7 no.
WCX grille
3 no.
ahu
1 no.
buffer
2 no.
connection
1 no.
dosing
1 no.
| 1000x250 | 7.8 |
|---|---|
| 1000x300 | 20.7 |
| 1200x300 | 11.2 |
| 300x200 | 2.4 |
| 300x250 | 14.9 |
| 300x300 | 8.4 |
| 400x250 | 14.2 |
| 400x300 | 5.2 |
| 500x300 | 7.8 |
| 700x250 | 7.5 |
| 800x250 | 7.2 |
| 900x250 | 7.5 |
| Ø125 | 6.0 |
| Ø160 | 12.4 |
| Ø200 | 19.4 |
| Ø250 | 104.3 |
| Ø315 | 11.7 |
| CHW DN15 | 1.8 |
|---|---|
| CHW DN20 | 32.0 |
| CHW DN25 | 72.6 |
| CHW DN32 | 15.7 |
| CHW DN40 | 15.0 |
| CHW DN50 | 43.2 |
| CHW DN65 | 27.5 |
| CHW DN80 | 0.8 |
| LTHW DN15 | 141.4 |
| LTHW DN20 | 9.9 |
| LTHW DN25 | 30.0 |
| LTHW DN32 | 55.7 |
| LTHW DN50 | 0.8 |