Pump Sizing Calculator for District Heating
Operating point, pump power and annual electricity demand
The calculator determines the design operating point of a heat network pump: flow rate and pump head from network heat output, temperature spread and the pressure losses along the most critical supply path. It also estimates the electrical pump power and the annual electricity demand.
Preliminary sizing of the network pump — operating point, pump power and annual electricity demand from network capacity, spread and pressure losses.
- Pump head
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- Hydraulic power
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- Electrical power
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- Annual electricity
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- Pump electricity share
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Assumptions: Δp = 2 · R · L (supply and return of the most critical path) + allowance for generator, transfer station and fittings · fluid properties at mean temperature — heating water 70 °C (ρ = 978 kg/m³, cₚ = 4.19 kJ/(kg·K)), water 10 °C (ρ = 1000 kg/m³, cₚ = 4.19 kJ/(kg·K)), water-glycol 30 vol% (ρ = 1040 kg/m³, cₚ = 3.7 kJ/(kg·K)) · P_el = V̇ · Δp / η with the total efficiency η of hydraulics, motor and drive (typically 0.60–0.75) · annual electricity via equivalent full-load hours f_part-load · t_operation (typically 1500–3000 h/a). The tool provides a preliminary sizing of the nominal operating point and does not replace a hydraulic network calculation with part-load profiles. Last updated: July 2026. VICUS Software accepts no liability for the correctness of the results.
How the calculator works
The design flow rate follows from the network heat output and the spread. The required pressure rise comprises supply and return of the path to the critical consumer plus an allowance for the heat source, substation and fittings:
V̇ = Q̇ / (ρ · cp · ΔT) Δp = 2 · R · L + Δpallowance H = Δp / (ρ · g)
Electrical power follows from the overall efficiency of hydraulics, motor and frequency converter; the annual electricity demand from equivalent full-load hours:
Phyd = V̇ · Δp Pel = Phyd / η Wa = Pel · tfull
- Typical overall efficiencies are 0.60–0.75, equivalent full-load hours 1500–3000 h/a.
- If the annual heat delivered is entered, the tool checks the pump electricity share against the 1–2 % guide value.
- Fluid properties at mean temperature (heating water 70 °C; water or water-glycol 30 % at 10 °C).
- The result is the nominal operating point. Part-load behaviour, control strategy and pressurisation are not modelled.
Background and theory
Pump curves, system curve, speed control and typical efficiencies are explained in the knowledge article pump sizing for district heating networks.
For a full thermo-hydraulic network simulation with annual load profiles, heat losses and pump energy for every pipe, use VICUS Districts.