Different types of water pumps in Solar Off-grid Mode

Water is the source of life, without it, especially without liquid water, there will be no life at all. And since the sources of water are always far away from the place of using it, people develop different techniques to transport it and store it, they develop different ways of pumping based on the conversion of mechanical energy.
Water Pumping System using Gravity
The evolution of pumping systems was developed so many years ago by using the parameters; gravity and pressure, but the appearance of electricity and motors marks the evolution of pumping technology by presenting a huge selection of pumps compatible with different applications.
Water Pumping System using pressure

Pumping is not related to water only, all pumping technologies are used also for oil and other liquids. But in this article, we are going to talk about water pumping only, at the same time, we will not take in consideration :

        • Water stations for big cities or Municipale water treatment
        • Sewage Treatment
        • Fire protection
        • Industrial processing

Our main focus will be on irrigation and domestic water supply.

Different application of pumping systems

For Irrigation:

Submersibles & Surface Pumps for Irrigation

Immersed or Submersible Pump:
This type of pump is commonly used to pump water from wells, sumps and other bodies of water, and it’s considered the most used pump for irrigation and also in some domestic cases. The device is composed of two units, the electric motor and the impeller (turbine) and it can be connected through a variable frequency drive or other electronic devices to optimize the consumption or maintain the flow and pressure depending on the needs.

Surface pump:
This type of pump is used to pump water from ponds, lakes, rivers and other surface water sources. Also used to distribute water to different points while maintaining the same pressure (drop by drop system). Most of the time, the surface pump is a centrifugal one which transports water from a place to another using the centrifugal force. But in some few cases, we can find another technology used in surface pump which is based on the movement of a piston or diaphragm back and forth (reciprocating)

Other types of Pumps for Irrigation:

For irrigation systems, we can find many other different types of pumps such as doser pumps, mixing pumps and injection pumps. Depending on the earth & plant type, the farmer needs to inject many products with water to assure better production in terms of quantity and quality.
Injection Pumping System
Automatic Doser Pump

For Domestic Uses

Pool Pumping system:

Swimming Pool Filter Pump
The circulation of water through the filter, heater and sanitizer is done by a specific pool pump to keep the water clean and healthy. There are two types of pumping systems for pool applications; single-speed pumping and variable-speed pumping, for both systems we can use the same pump and add variable frequency drive for the second application. Variable-speed pumping is more energy efficient than single-speed and they can save money and energy bills

Booster Pump:

In case the water system is not able to deliver enough pressure, the booster pump can provide additional pressure. There are two main types of booster pumps; centrifugal pump which is the most common type of booster, it work by using centrifugal force to move water through the pump, and positive displacement pumps which works by trapping a certain quantity of water and forcing it out of the pump.

Different PV solutions for pumping systems

Off-Grid Solutions

Immersed and Surface Pumps (pool pump also considered):

Depending on quantity of water demande, for this case the most valuable solution is using a Solar Pumping System with Variable Frequency Drives, the System will produce water during Solar PV production and use it directly or store it in a tank or lake.
This solution is so easy to make, and it contains few number of devices (PV array, VFD, Protection Accessories).

Solar Pumping System Diagram

Booster & Doser Pumps:
are most of the time single phase devices with less than 2 HP, using a variable frequency drive is not the right choice while those devices work a few minutes depending on the needs and their work is not related to Solar Intensity. In this case we advise using a small off-grid solution with one to two hours of autonomy in the batteries depending on night needs and solar conditions.

Injection & Mixing Pumps: For injection pump, it work normally at the same time with the pump of irrigation while the mixing pumps will work while the irrigation pump is not working, for this case and to optimize the cost, we can use the same irrigation solar system to bypass the energy and feed-in the Mixing pumps, while the injection pump can work in parallel with Irrigation pump.


In off-grid mode, and especially for power more than 2HP, it is always better to use a VFD and store water in the place of using battery storage, except in case of using a booster pump, but in general booster pump capacity is not so high and it’s very rare when we can see a booster working continuously for many hours. In the next parts of the article we will see other solutions under different conditions (Grid, Generator or other sources). At the same time we will size an example which covers most of the types of pumps in different PV solutions and we will make a technical and financial comparison.
Author: Abdellah Lhannaoui, Technical Engineer NA