DENOVA — Pump Sizer v1.26

Project Information

ℹ Report metadata that stamps the printed engineering report. None of these fields affect calculations — they're for documentation, drawings, and submittal tracking.

Project Name Client project identifier

Project Number Drawing or doc reference

Engineer Responsible engineer

Location Site or city

Pump Tag Equipment tag number

Date Issue date

Remarks Optional — duty notes or design basis

Ready to size your pump?

Continue to the Pump Sizing tab to enter circuit, flow, head, and motor parameters.

⚡ Quick start Replaces current form values · Schedule entries are preserved

Project Untitled · Tag: — · Engineer: — ✎ Edit details

1DutyCircuit, fluid, flow rate or load

Circuit Type

❄️

Chilled Water

6–12°C · ΔT 5–6°C

CHW

🌊

Condenser Water

30–35°C · ΔT 5–6°C

🔥

Heating Hot Water

60–82°C · ΔT 10–20°C

HHW

Fluid TemperatureAverage circuit temperature — °C

Glycol %Ethylene glycol by volume — %

Duty / Standby ArrangementPump configuration

Fluid Density (ρ)

—

Specific Heat (Cp)

—

Flow Rate

From Thermal Load

Enter Flow Directly

Thermal LoadCooling or heating — kW

Design ΔTSupply–return — °C

Calculated Flow

—

2Pipe & HeadPipe size, friction, system head losses

Pipe, Velocity & Friction

Nominal Pipe SizeSteel Schedule 40 — DN

Pipe Velocity

—

Velocity Status

—

Friction Method

Pipe Roughness (ε)Steel new = 0.046 mm · HDPE = 0.007 mm

Total Pipe LengthIndex circuit one-way run — m

90° ElbowsCount

Tee BranchesCount

Gate / Isolation ValvesCount

Calculated Pipe Friction

—

System Head

Static HeadOpen systems / elevation change — kPa (0 for closed loops)

Chiller DropPrimary equipment pressure drop — kPa

Coil / AHU DropHeating or cooling coil — kPa

Control Valve Drop2-way CV at design — kPa

Other LossesStrainer, NRV, misc — kPa

Safety MarginApplied to subtotal — % (typical 10–15%)

Total Dynamic Head (kPa)

—

Total Dynamic Head (metres)

—

3Motor & NPSHPump efficiency, motor sizing, suction check

Motor & Electrical (indicative)

⚠ Cable size, breaker rating, and starting method shown as preliminary indication only. Final electrical design must be verified by a licensed electrical engineer per local code (AS/NZS 3000, IEC 60364, NFPA 70, etc.) considering installation method, cable length, voltage drop, ambient temperature, grouping factor, and protection coordination.

Pump Efficiency (η_p) Estimated from manufacturer curves — %

Motor Efficiency (η_m)IE2/IE3 motor — %

Supply Voltage3-phase AC

Running Hours / YearAnnual operation estimate — hrs

Electricity TariffAverage cost per kWh — $/kWh

NPSH & Suction (open systems)

ℹ For closed pressurised loops: set Suction Tank Height = static fill head (m above pump suction), and Suction Pipe Losses ≈ 0 kPa. The atmospheric-pressure assumption still applies via the altitude correction.

Suction Tank HeightBelow tank water level — m (+ve = flooded)

Suction Pipe LossesFriction in suction line — kPa

NPSH RequiredFrom pump manufacturer — m

Site AltitudeAbove sea level — m (corrects P_atm)

NPSH Available

—

NPSH Margin

—

◇ Advanced · Optional Manufacturer curve override and closed-loop expansion vessel sizing — both safe to skip for preliminary work.

Optional: Manufacturer Q-H Curve Optional▾

ℹ Paste Q-H points from a manufacturer datasheet to replace the parabolic approximation. Format: Q (L/s), H (m) — one pair per line, comma or space separated.

Q-H Datasheet Points e.g. "0, 45" · "5, 40" · "10, 30" — Q in L/s · H in metres

Polynomial Fit Result

Enter ≥3 data points to fit curve

No custom curve loaded

Optional: Expansion Vessel Sizing Closed loops▾

System VolumeTotal fluid volume — litres

Cold Fill Temp.System fill / commissioning — °C

Max. Operating Temp.Highest fluid temp. in circuit — °C

Fill Pressure (kPag)Cold fill system pressure — kPa gauge

Max. System Pressure (kPag)Safety valve setpoint − 50 kPa — kPa gauge

Glycol De-rateFor glycol systems — add 10% margin

ℹ EXP.VESSEL — Sizing per EN 12828 / AS 4201. Results are preliminary estimates. Final sizing by mechanical engineer. Excludes pipe and equipment expansion above fill temperature. Pre-charge pressure = fill pressure (kPag).

4Review & ScheduleCalculation health, results, add to schedule

📈

No analysis available yet

Analysis tools (interactive Q-H curves, VSD energy modelling, life-cycle cost, system sensitivity) become available once you've sized a pump.

Performance Curves

Impeller Trim Full diameter → trimmed: 100%

VSD Speed Affinity laws — H∝N², Q∝N, P∝N³: 100%

⚠ Illustrative curve only — synthetic Q-H curve generated from the duty point using typical centrifugal-pump shape factors. Not a manufacturer pump curve. For actual selection, use Optional: Manufacturer Q-H Curve on the Pump Sizing tab.

━ H-Q Curve ╌ System ┈ Efficiency ─ Power ● Duty ○ BEP POR

System Sensitivity

System Resistance Variation Drag to see duty point shift: +0%

VSD Energy Analysis

Part-Load ProfileAnnual load distribution

VSD EfficiencyDrive + motor — %

Analysis PeriodYears for LCC

Part-Load Profile

Load %	Flow (L/s)	Head (m)	Speed %	Fixed kW	VSD kW	Saving	Hours	Fixed kWh	VSD kWh

Parallel Pump H-Q

ℹ Shows combined operating curve for 2 identical pumps in parallel vs single pump duty. Critical for 2D+1S and 2+1 arrangements.

Life Cycle Cost

Specific Speed

Equipment Schedule

📋

No pumps in schedule yet

Size a pump on the Pump Sizing tab, then click Add Pump to build your equipment schedule. Or load a sample project to see how it works.

Formulas & Methodology

Flow Rate

Q (L/s) = Load (kW) / [ρ (kg/m³) / 1000 × Cp (kJ/kg·K) × ΔT (°C)]

Fluid density and specific heat corrected for temperature and glycol concentration. Ethylene glycol: ρ increases ~1.1 kg/m³ per % glycol. Cp decreases ~0.012 kJ/(kg·K) per % glycol.

Pipe Friction — Darcy-Weisbach

ΔP = f × (L_eq / D) × (ρV² / 2) [Pa → ÷1000 = kPa]
Colebrook-White: 1/√f = −2 log₁₀[ε/(3.7D) + 2.51/(Re√f)]
Re = ρVD / μ (μ_water ≈ 0.001 Pa·s at 20°C)
Equivalent lengths: 90° elbow = 30×DN, Tee branch = 60×DN, Gate valve = 8×DN (m)

Roughness values (ε): Steel new = 0.046 mm, Steel aged = 0.1–0.3 mm, Cast iron = 0.26 mm, HDPE = 0.007 mm, GRP = 0.01 mm. Schedule 40 internal diameters per ASME B36.10M.

Power Chain

P_hydraulic (kW) = Q (L/s) × TDH (kPa) / 1000 = ρgQH
P_shaft (kW) = P_hyd / η_pump
P_motor_input (kW) = P_shaft / η_motor
IEC motor: next standard size above P_motor_input (service factor = motor_std / P_motor_input)

IEC 60034 standard sizes (kW): 0.37, 0.55, 0.75, 1.1, 1.5, 2.2, 3.0, 4.0, 5.5, 7.5, 11, 15, 18.5, 22, 30, 37, 45, 55, 75, 90, 110, 132, 160, 200, 250, 315. Target service factor: 1.10–2.00.

NPSH Available — with Altitude Correction

NPSHa (m) = P_atm/(ρg) + Hs − Hf − Pvap/(ρg)
P_atm(Z) = 101.325 × (1 − 2.25577×10⁻⁵ × Z)^5.25588 [kPa, Z = altitude m]
Pvap (kPa) = 10^[8.07131 − 1730.63/(233.426+T)] × 0.133322 (Antoine equation)
Minimum margin: NPSHa − NPSHr ≥ 0.5 m (preferred ≥ 1.0 m)

At 1000 m altitude, P_atm ≈ 89.9 kPa vs 101.3 kPa at sea level — a reduction of ~1.2 m head equivalent. Critical for high-temperature systems and suction lift applications above 500 m.

Motor & Electrical — Preliminary Indication

I_FLA (A) = P_motor (kW) × 1000 / (√3 × V × PF × η_motor)
PF ≈ 0.87 (typical HVAC induction motor, 415V, IE2/IE3)
I_breaker = 1.30 × I_FLA → next standard MCB/MCCB size
Starting: DOL ≤4 kW · Star-Delta 4–22 kW · Soft Starter 11–75 kW · VSD ≥75 kW or variable flow

Disclaimer: Electrical estimates are preliminary indications only. Final electrical design by a licensed electrical engineer is mandatory. Comply with AS/NZS 3000, IEC 60364, NEC, or applicable local standard.

Affinity Laws (VSD / Impeller Trim)

Q₂/Q₁ = N₂/N₁ (flow ∝ speed)
H₂/H₁ = (N₂/N₁)² (head ∝ speed²)
P₂/P₁ = (N₂/N₁)³ (power ∝ speed³ — major energy saving at part-load)
Also applies to impeller trim within ≈10% trim range (consult mfr beyond 10%)

Specific Speed Classification

Ns = N × √Q / H^0.75 (N = rpm, Q = m³/s, H = m)

Ns Range	Impeller Type	Typical HVAC Application
10–50	Radial high-head	Multistage booster, high-rise distribution
50–200	Standard centrifugal radial	HVAC end-suction, inline, split-case — most common
200–500	Mixed radial / mixed flow	Large volume, moderate head — split-case, large inline
500–1000	Mixed flow / axial	Very high flow, low head — large condenser water plants

Expansion Vessel Sizing (Closed Loop)

V_exp (L) = V_system × (ρ_cold / ρ_hot − 1) × glycol_factor
V_vessel (L) = V_exp × P_max_abs / (P_max_abs − P_fill_abs)
Pre-charge pressure = P_fill (gauge)
Absolute pressure = gauge pressure + 101.3 kPa

Scope: Covers thermal expansion of fluid only. Does not include pump/pipework expansion, initial air purge volume, or makeup allowance. Per EN 12828 / AS 4201.
System volume estimate: ~10–15 L/kW for LTHW, ~6–10 L/kW for CHW systems. Verify with pipe schedule.

Glycol Viscosity & HI Pump Correction

ν (cSt) — kinematic viscosity of EG solution (ASHRAE data)
μ (Pa·s) = ν × ρ / 1,000,000 [used in D-W Reynolds number]
HI 9.6.7 correction: C_Q = f(ν) · C_H = f(ν) · C_η = f(ν)
Approximate: C_H ≈ 1 − 0.007×(ν−1)^0.75, C_Q ≈ 1 − 0.0045×(ν−1)^0.75

Important: D-W friction factor in this tool is corrected for glycol viscosity (μ varies with concentration and temperature). However, pump H-Q curve de-rating is advisory only — actual corrections require manufacturer-supplied glycol curves per HI 9.6.7.

EG %	ν at 5°C (cSt)	ν at 20°C (cSt)	Est. C_Q at 5°C	Est. C_H at 5°C
0%	1.52	1.00	1.000	1.000
20%	3.5	2.1	0.989	0.982
30%	5.5	3.2	0.980	0.967
40%	9.5	5.5	0.965	0.943
50%	16.0	9.0	0.946	0.913

Custom Pump Curve — Polynomial Fit

H(Q) = a₀ + a₁·Q + a₂·Q² (quadratic least-squares fit)
Actual operating point: solve (a₂ − R)·Q² + a₁·Q + (a₀ − H_static) = 0
Affinity law at speed N/N₀ = sp: H_new(Q) = a₀·sp² + a₁·sp·Q + a₂·Q²

Input format: Paste Q (L/s) and H (m) pairs from manufacturer datasheet. Minimum 3 points recommended 5–6. Best practice: include shutoff head (Q=0), BEP, and runout (near max Q). The polynomial is fitted by least-squares — R² ≥ 0.995 indicates an excellent fit. The actual operating point is computed by finding the intersection of the fitted curve with the system resistance curve.

Pump Family Selection Guide

Pump Family	Flow Range	Head Range	Open / Closed	Typical Application	Key Feature
Inline Circulator	0.1–5 L/s	0–25 m	Closed only	Small FCU loops, fan coil circuits	Wet rotor, no seal, no alignment
Close-Coupled End-Suction	1–35 L/s	5–70 m	Both	HVAC primary / secondary loops	Compact, most widely specified
Frame-Mounted End-Suction	3–100 L/s	5–90 m	Both	All-purpose HVAC, chiller plant	Best range, easy impeller trim
Vertical In-Line	2–60 L/s	5–60 m	Both	Variable-flow secondary, AHU	Pipe-mounted, space-saving
Horizontal Split-Case	20–500 L/s	10–120 m	Both	Large chiller plant, district cooling	Double suction, long life
Vertical Multistage	0.5–40 L/s	30–300 m	Closed	High-rise, booster sets	Compact, high-head
Horizontal Multistage	0.5–50 L/s	25–200 m	Both	Booster, high-pressure closed loops	Easier service than vertical
Packaged Booster Set	0.5–80 L/s	20–250 m	Both	Domestic water, fire suppression	Factory package with controls

HVAC Design Parameters

System	Supply Temp.	Return Temp.	Design ΔT	Pipe Velocity Target
Chilled Water (CHW)	6–7°C	11–13°C	5–6°C	1.2–2.5 m/s
Condenser Water (CW)	29–32°C	35–37°C	5–6°C	1.5–2.5 m/s (open system)
Low Temp. Hot Water (LTHW)	70–82°C	60–70°C	10–12°C	1.0–2.0 m/s
Medium Temp. HW (MTHW)	85–120°C	75–105°C	10–20°C	1.0–2.0 m/s
Domestic Hot Water (DHW)	60–65°C	—	—	1.0–2.0 m/s

IEC Motor Reference

kW	HP (approx)	IE2 η %	IE3 η %	Est. FLA @ 415V	Indicative Cable	Breaker (est.)

Assumptions

Fluid Properties: Water: ρ = 1000.6 − 0.0128(T−4)² kg/m³. Ethylene glycol correction applied as simplified linear model. For glycol >30% or T outside 5–60°C, use viscosity-corrected Darcy-Weisbach — pump manufacturer de-rated curves are essential.

Pump Efficiency: Preliminary ranges: small pumps Q <5 L/s → η 55–65%; medium 5–30 L/s → 65–75%; large >30 L/s → 72–82%. Verify against manufacturer catalogue data before finalising selection.

Energy Estimate: Annual kWh = motor_kW × hrs/yr × 0.75 average load factor. For accuracy, use full part-load profile analysis via the Analysis tab (VSD Energy section).

Glycol De-Rating: This tool does not automatically de-rate pump curves for glycol concentration. For glycol ≥20%, obtain manufacturer de-rated H-Q curves. Correction typically reduces head and efficiency while increasing motor power. Confirm shaft seal and O-ring material compatibility.

Pump Curves: H-Q and efficiency curves are mathematically generated approximations based on the duty point and assumed parabolic curve shape. These are for visualisation only — obtain actual manufacturer curves for final selection, commissioning, and VSD programming.

General Disclaimer: DENOVA Pump Sizer Lite v1.26 is a preliminary engineering tool for concept design and early-stage project support. All results must be independently verified by a qualified mechanical engineer. Not for use as a construction document without independent review. Electrical sizing is indicative only — final design by a licensed electrical engineer. DENOVA Engineering.

Pump Family Matrix

D-W Pipe Friction

Motor & Electrical

NPSH + Altitude

Interactive Curves

Submittal Report