Pumps, Motors and Chillers — Calculator guides — Workspace
Motor Power, Pump Flow Rate, Chiller TR Load, Chiller Flow Rate and Heat Loss: inputs, method and gotchas.
What these calculators are for
Five calculators in Utilities & Services Engineering
size the rotating equipment and cooling loads of a plant: the motor a pump
needs, the flow a motor can deliver, the tonnage a chiller must carry, the
flow a chiller needs, and the heat a motor gives off into its room.
Motor Power
Inputs
Media — Water or Oil.
Flow rate — m³/hr, LPM, L/sec, US GPM or
m³/sec.
Head — m, mm, cm, ft or inch.
Efficiency pump — 0.55, 0.6 or 0.7.
Efficiency motor — 0.6, 0.75 or 0.8.
How it is calculated
Flow is converted to m³/sec.
Density is taken as 1000 kg/m³ for water and 850 kg/m³ for
oil.
Hydraulic power (kW) = flow × head ×
density × 9.81 ÷ 1000.
Pump power (kW) = hydraulic power ÷ pump
efficiency.
Motor power (input) (kW) = pump power ÷ motor
efficiency — the power the motor draws.
Typical use and gotchas
Use it to choose a motor for a known duty point. The result is the
calculated power; pick the next motor size above it yourself.
Flow rate and head must both be above 0; a zero or negative value…