Solar Water Pumping System SS2 Solar Photovoltaic Installation & Maintenance Lesson Note

What is a Solar Water Pump?

In many parts of Nigeria, farmers struggle to get water to their crops. Using a petrol generator is expensive because fuel prices keep rising. A Solar Water Pump uses the sun’s energy to lift water from a borehole or a stream and push it to where it is needed.

The big difference: A standard solar system uses batteries to store energy. In a basic solar pumping system, we often don’t use batteries. Instead, we pump as much water as possible while the sun is out and store the water in a high tank.

Why skip batteries? Water tanks are cheaper and last longer than chemical batteries!

The Main Parts of the System

To design a system, you need to know these four parts:

1. The Solar Array: These are the panels that catch the sun.
2. The Controller (The Brain): This sits between the panels and the pump. It makes sure the pump doesn’t “struggle” when the sun is weak (like in the early morning).
3. The Pump: This is the motor that moves the water.
   1. Submersible Pump: Stays inside the borehole underwater.
   2. Surface Pump: Sits on the ground near a river or well.
4. The Storage Tank: This acts like your “battery.” It holds the water for use at night or on cloudy days.

Designing the System (The “Lift” Logic)

When designing, we don’t just guess. We need to measure the Total Dynamic Head (TDH). This is a fancy way of saying “How hard does the pump have to push?”

To find the “Head,” you add two things:

• Vertical Lift: The distance from the water level in the ground to the top of the tank.
• Friction Loss: The “resistance” the water feels as it rubs against the inside of the pipes. Long, thin pipes make the pump work harder.

Simple Calculation Step: If your borehole is 30 meters deep and your tank is 5 meters high, your total lift is 35 meters. You must choose a pump that is strong enough to “push” water that high.

Applications in Agriculture

How does this change a farm? In SS2 Agricultural Science, we learn about irrigation. Solar makes it automatic.

• Drip Irrigation: The solar pump fills a tank, and the tank slowly “drips” water directly onto the roots of the plants. This saves water and energy.
• Livestock Watering: Cattle and poultry need a constant supply of fresh water. Solar pumps ensure the troughs are always full without the farmer having to be there to turn on a generator.
• Year-Round Farming: In the North or during the dry season, farmers can grow crops like tomatoes and onions even when there is no rain, simply by “harvesting” the sun.

Maintenance and Safety

Solar pumps are “set and forget,” but they still need a little love to last 20 years.

1. Clean the Panels: Dust and bird droppings act like a “blanket” over the panels. A quick wipe with water once a week can increase water flow by 20%.
2. Dry Run Protection: If the borehole goes dry, the pump can burn out. A good controller will have a sensor that turns the pump off if there is no water.
3. The “Vermin” Problem: In a farm environment, rats love to chew on wires. All cables should be hidden in metal or thick plastic pipes (conduits).

Summary for the Designer:

• First, find out how much water the farm needs per day (in Liters).
• Measure the depth of the water (The Head).
• Size your panels to provide enough power even on “hazy” days.