Pump Power Calculator

Calculate the required pump power for a given flow rate and head (or pressure difference).

Calculate Pump Power

Calculate Pump Power (P = (ρ ⋅ g ⋅ Q ⋅ H) / η)

Pump power represents the energy required to move a fluid at a given flow rate and head (or pressure difference). The calculation can be made at different levels as hydraulic power, shaft power and motor power.

Hydraulic Power (Power Transferred to Fluid):

P_hydraulic = ρ ⋅ g ⋅ Q ⋅ H

P_hydraulic = Q ⋅ ΔP

**ρ:** Fluid density (kg/m³)
**g:** Gravitational acceleration (9.81 m/s²)
**Q:** Volumetric flow rate (m³/s)
**H:** Total head (m)
**ΔP:** Pressure difference (Pa)

Shaft Power (Pump Input Power):

P_shaft = P_hydraulic / η_pump

**η_pump:** Pump efficiency (in decimal, for example 0.75 for 75%)

Engine Power (Including Pump and Engine Efficiency):

P_motor = P_shaft / η_motor

**η_motor:** Motor efficiency (usually between 85-95%)

This calculator gives the hydraulic power and pump shaft power in Watts as a base. If necessary, you can perform an additional efficiency calculation for the motor power.

What are Pump Power Calculations?

**Pump power calculations** are performed to determine how much energy (power) a pump needs to move a given fluid at a desired flow rate and head (or pressure difference). These calculations are critical in pump selection, system design, and energy consumption analysis.

Basic Types of Power:

**Hydraulic Power (Fluid Power, Water Horsepower):** It is the net power transferred by the pump to the fluid. It is the minimum power theoretically required to move the fluid, excluding friction losses and other inefficiencies.
P_hydraulic = ρ ⋅ g ⋅ Q ⋅ H (In terms of Head)

P_hydraulic = Q ⋅ ΔP (In terms of pressure difference)
- **ρ:** Fluid density
- **g:** Gravitational acceleration (approximately 9.81 m/s²)
- **Q:** Volumetric flow rate
- **H:** Total discharge head (equivalent height of total pressure energy provided by the pump)
- **ΔP:** Pressure difference between the inlet and outlet of the pump
**Shaft Power (Input Power):** The power applied to the shaft to turn the pump impeller. It is greater than hydraulic power because the pump has its own internal friction and mechanical losses. Pump efficiency takes these losses into account.
P_shaft = P_hydraulic / η_pump
- **η_pump:** The efficiency of the pump (usually a decimal value between 0.5 and 0.9).
**Motor Power (Electrical Input Power):** The electrical power drawn by the motor that powers the pump. It is greater than the shaft power because the motor has its own electrical and mechanical inefficiencies.
P_motor = P_shaft / η_motor
- **η_motor:** The efficiency of the motor (usually a decimal value between 0.85 and 0.95).

Application Areas:

Liquid Transfer Systems: Water supply, wastewater treatment, chemical processes and oil/gas pipelines.
HVAC Systems: Water circulation pumps in cooling and heating systems.
Construction Industry: Site drainage, concrete pumps.
Agriculture: Irrigation systems.
Marine: Ship engine cooling systems, ballast pumps.

This calculator is based on the basic hydraulic principles of pump power and includes the concept of efficiency. In real world applications, additional factors such as pipeline friction losses, static head, velocity head, cavitation risk (NPSH), fluid viscosity and temperature can affect the total head of the system and pump performance. Detailed engineering analysis, pump characteristic curves and expert knowledge are required for precise pump selection and system design.