Water pumps are machines for moving water, they play a fundamental part in agriculture as they move water from its source to the fields and crops. Water pumps can be used with many forms of irrigation, such as drip, sprinklers or with a hose.
There are a wide range of water pumps available, from simple manually operated pumps to those powered by fossil fuels or electricity.
How do water pumps work?
Water pumps can work in a few different ways, but in the simplest terms, water pumps consist of three main parts: an inlet, pump system and an outlet.
Water is drawn into the pump though the inlet side when a pressure difference is made within the pump system, the water wants to move from an area of high pressure to an area of low pressure. This is used to move the water through the pump to the outlet side, into a hose, and towards your farm or water tank.
There are two main types of water pumps, and they are categorised in how they create the pressure difference within the pump system. These types are:
- Positive Displacement Water Pumps – create a pressure difference by changing the available space (volume) within the pump system. Using components such as; pistons, closed chambers and valves, the pressure is decreased on the inlet side which draws water into the pump. Then the pressure is increased forcing (displacing) the water through the outlet side of the pump system. (The Futurepump SF2 is an example of this!)
- Centrifugal Water Pumps – use rotating blades, known as impellers, which pass energy from the rotation into the water flow to drive the water through the pump system.
Something in common with these pumps is that they need energy to work, this energy can come from fuel or electricity, or with a bit of effort, from you manually moving the pump parts with a lever.
What different water pumps are there for smallholder farmers?
There are many different types of water pumps available and it can get quite confusing which options are best and most suitable for your farm. Budget, farm size, water source, how much water you need, and power source all need to be considered when choosing a water pump.
Your water source will play a big part in which water pumps are suitable for you. If you have a water source at the surface such as a river, lake, water pan, tank or even a very shallow well or borehole with a water level between 0 at 7m (0 and 23ft) then a Surface Water Pump will be suitable for you.
If the water source is deeper than this, you will need a Submersible Water Pump. This is because pumps that are placed on the surface cannot physically lift water from any deeper down than 7m. The height a water pump can lift water is known as its Total Head (or total lift).
- Surface water pumps are pumps placed on the ground, out of the water, with a hose from the inlet side of the water pump placed into the water. These pumps suck water up to the pump system and then push water to your farm.
- Submersible water pumps are lowered into the water. They have power cables and the outlet hose attached to the pump under the water, so these pump systems need to be water tight to work. These pumps push the water up from the pump’s depth to your farm.
The amount of water pumped, known as the flow rate, will vary depending on your pump type and power source.
In general, the greater the distance the water needs to be lifted (a bigger head) the lower the flow rate will be, as more energy is required to move the water. So, if you put the same energy in to each, pumping water with submersible pumps from greater depths (large head) will produce less water than a surface water pump from shallow sources (low head).
This works the same with your power source, the more power your pump has the higher the flow rate.
How should you power your water pump?
As we said above, all water pumps need energy to work…
Across the tropics, petrol and diesel water pumps remain popular, as they can look like the cheapest option in the shop. However, there are many ongoing costs for these pumps that pushes their price up over the lifetime of the pump.
Fossil fuel pumps tend to have short lifespans, needing regular maintenance from a mechanic and you’ll need to keep buying fuel. On top of that, they are very polluting, lowering the air quality on your farm and producing carbon dioxide which contributes to climate change which has been found to influence the regularity of the dry/wet seasons.
Another option is manual water pumps, such as the treadle pump. These require you to manually pump the pump, often with your feet. However, these type of water pumps, whilst affordable, require a lot of your time and labour.
In contrast, if you have a solar water pump, the solar panels will keep providing free and clean energy for your pump as solar energy is available everywhere, all day for free! This means, you don’t need to be connected to the electricity grid or travel to purchase more fuel. In addition, the only servicing you need to do is give the panels a wipe every so often to get the dirt and dust off and you’re good to go. This is why we truly believe renewable solar energy is the best way for a smallholder farmer to power their water pumps.
By powering your water pump with solar energy, you will:
- Save money, as you do not need to buy fuel
- Have more time to do other things, as no labour is needed to pump the water
- Be able to maintain your water pump yourself
- Be able to irrigate in an environmentally friendly and sustainable way
The Futurepump SF2 solar pump
The Futurepump SF2 is a surface solar water pump, and consists of a motor, flywheel and piston powered by solar panels. This simple system has fewer moving parts than petrol or diesel pumps and is accessible and easy to maintain by yourself!
Set up is easy, just place the solar panels in a sunny spot on your farm, plug them into the water pump, connect your hoses (and any irrigation methods you have) and get your crops growing.
If you want to find out more about the Futurepump SF2 solar pump you can get all the technical details on our solar water pump datasheet.