Digital Engineering

AHU Fan Performance Simulator

v2.43 · Bounded-curve solver repair

GUIDED FAN ANALYSIS

Start with the design maturity, then move through one clear stage at a time.

A structured workflow for concept fan-law analysis, manufacturer-curve selection, operating-point review, and IES-VE part-load schedules.

01Choose pathwayEarly stage or detailed design

02Define dutyAirflow, pressure and speed

03Review & exportPerformance, curves and DSM

Single-file engineering tool. Project data remains in the browser and can be exported as portable JSON.

Choose an analysis pathway You can switch pathway later without losing the current inputs.

Speed621 rpm

Airflow1.33 m³/s

Pressure327 Pa

FanLensFan curve analysis and part‑load schedules

Guided concept and detailed-design fan analysis Fan laws, manufacturer curves and IES-VE DSM Single-fan workflow v2.43

PProject save, autosave and filesSave in this browser, restore the last session, or export a portable project file.Project 1

1Design inputsSet airflow, static pressure, fan-speed limits and the current operating demand.

2Part-load scheduleReview the fan-law output and copy the normalised flow and power fractions into IES-VE.

Stage 1

Define design and operating duty

Set airflow, static pressure, fan-speed limits and the current operating demand.

1 of 2

Flow Rate

1.497 m³/s

Fan Speed

300 rpm

Fan static Δp

64 Pa

P_brake

0.13 kW

P_elec

0.14 kW

η overall

0.668

Fan control strategyChoose this before entering the operating condition. The selection is synchronised between Early Stage and Detailed Design.

Required choice

Variable speed selected. RPM changes with airflow demand; minimum VSD speed is active and the IES-VE Q/Qd–P/Pd curve is generated automatically.

LIVEAHU airflow and pressure animationFan speed and airflow motion respond to the active design or operating point.

View Fan Fan operation view — VSD fan/system intersection

Live visual: airflow particles, fan rotation, component pressure drops and duty values update with the inputs.Use the View control above the animation.

Early-stage pathway. Define the concept duty point here, then continue to the IES-VE Part-Load stage. Manufacturer curves and engineering selection are available in Detailed Design.

Early-stage fan-law analysis

Physics laws only · Q∝n Δp∝n² P∝n³ · No experimental or manufacturer data involved. Enter the design duty point and operating demand — all outputs are derived directly from first principles. Switch to Detailed Design when manufacturer test curves are available.

01System design dutyEnter the concept design airflow and static pressure requirement.8.40 m3/s | 930 Pa

02Fan speed and VSD limitsSet maximum speed, design selection and minimum controllable speed.1450 rpm max | 30% min

03Operating airflowMove the live operating point within the allowable VSD range.3.75 m3/s operating

04Live fan-law resultsReview the calculated speed, pressure, power, SFP and specific speed.300 rpm | 0.14 kW

05IES-VE part-load dataOpen the generated Q/Qd and P/Pd schedule only when it is needed.11 schedule points | P proportional to Q^3

IES-VE Part-Load Schedule · Variable Speed Fan Law (P ∝ Q³)

Design flow Q_d

1.40 m³/s

Design ΔP

420 Pa

Design P_elec

0.97 kW

n_design / n_max

1160 / 1450 rpm (80%)

Q_min at n_min

0.52 m³/s  (30% of n_max)

Min Q/Q_d fraction

0.375

Rows generated from 100% down to the minimum speed entered above. The minimum is always included as the final row. Use Q/Q_d and P/P_d columns directly in IES-VE fan schedule (Apache Systems → Fan → Part-load curve → User defined).

Flow %	Q (m³/s)	n (rpm)	Fan/System ΔP (Pa)	P_shaft (kW)	P_elec (kW)	Q / Q_d	P / P_d	SFP W/(l/s)
100% Qd	1.400	1160	420	0.905	0.973	1.000	1.0000	0.695
94% Qd	1.313	1088	369	0.745	0.801	0.938	0.8240	0.611
88% Qd	1.225	1015	322	0.606	0.652	0.875	0.6699	0.532
81% Qd	1.137	943	277	0.485	0.522	0.813	0.5364	0.459
75% Qd	1.050	870	236	0.382	0.410	0.750	0.4219	0.391
69% Qd	0.962	798	199	0.294	0.316	0.688	0.3250	0.328
63% Qd	0.875	725	164	0.221	0.237	0.625	0.2441	0.271
56% Qd	0.787	653	133	0.161	0.173	0.563	0.1780	0.220
50% Qd	0.700	580	105	0.113	0.122	0.500	0.1250	0.174
44% Qd	0.612	508	80	0.076	0.081	0.438	0.0837	0.133
38% Qd ← min flow	0.525	435	59	0.048	0.051	0.375	0.0527	0.098

Component	Operating assumption	Operation Δp
① Filter	average filter curve, n=1.6	26 Pa
② Heat Exchanger	typical HX curve, n=1.8	12 Pa
③ Heating Coil	typical coil curve, n=1.8	1 Pa
④ Cooling Coil	typical coil curve, n=1.8	6 Pa
⑤ Duct/Friction	turbulent duct/fitting curve, n=2.0	19 Pa

01Engineering design duty checkCheck selected duty, required RPM and motor brake-power adequacy.Live selection status

02Design versus operating pressure breakdownCompare component design pressure with the current operating condition.872 Pa design total

IES-VE Part-Load Schedule — Early Stage Physics laws · no manufacturer data

01Schedule basis and design pointReview the fan-law basis and the values used to normalise the schedule.8.40 m3/s design | 1450 rpm max

02IES-VE part-load schedule tableOpen the table to copy the Q/Qd and P/Pd fractions into IES-VE.11 generated points

IES-VE Part-Load Schedule · VSD Fan Law (P ∝ Q³)