In this post I want to share a handy method to estimate **pump power requirement**. Pump power is a function of these parameters:

- Flow rate
- Delivered pressure
- Pump efficiency

If the flow rate in US gallon per minute (USgpm) and delivered pressure is in psi, then use the equation below to estimate pump power:

** Pump Power Requirement (HP) = Flow rate (GPM) x ∆P / (1715 x Eff)**

Where:

∆P = delivered pressure (discharge minus suction), psi

Eff = pump efficiency

If the flowrate in m^{3}/h and delivered pressure is in bar, then use the following equation:

** Pump Power Requirement (kW) = Flow rate (m ^{3}/h) x ∆P / (36.01 x Eff)**

Where:

∆P = delivered pressure (discharge minus suction), bar

*How to determine pump efficiency?*

The pump efficiency will depend on the type of pump used and the operating conditions. In this post, I shared how to estimate pump efficiency as a function of head and flow rate. For preliminary purpose, the following graph can be used to estimate pump efficiency of centrifugal pump.

In this spreadsheet I shared above pump power calculation. I hope you find this useful.**Reference:**

- Branan, Carl,
*Rules of Thumbs for Chemical Engineers*, Gulf Professional Publishing, 2005. - Sinnot, R.K.,
*Chemical Engineering Design Volume 6*, Elsevier Butterworth-Heinemann, 2005. - Feature image by Denny Müller on Unsplash