Solar Pump Questionnaire
OVERVIEW: Solar water pumps enable you to move water from its remote source to where you need it, without access to power lines. Solar pumping has three primary uses; domestic use for washing, cooking and drinking, livestock watering, and irrigation.
The same basics are used for all three requirements, although domestic use may require additional capabilities.
Solar water pumps are different from regular AC powered pumps in more ways than the simple fact that they use DC power instead of AC. Most solar pumps are designed to be used in off-grid situations, and are designed to be extremely efficient. By not experiencing losses when going from DC to AC and back to DC, you can maximize your pumping while minimizing your power use.
DC powered pumps use direct current from motor, battery, or solar power to move fluid in a variety of ways. Motorized pumps typically operate on 12, 24,32 OR 48V volts of DC power. Solar-powered DC pumps use photovoltaic (PV) panels with solar cells that produce direct current when exposed to sunlight.
The most efficient way to use a solar pump is PV-direct, powering the pump directly off the solar panel, without using batteries. Rather than experiencing losses through storing power in batteries, the water itself is stored in a cistern or tank to be used when needed. It’s much easier to store water than power. The difference between a cistern and a tank is a cistern has a removable lid, and a tank is generally sealed.
A float switch can be connected to control when to turn the pump on or off based on the water level. A pump up switch will turn the pump on when the tank is low, and off when it is full. It is also known as a full tank shut off switch. A pump down float will turn on the pump when the tank is full, and off when it is empty. It is also known as an empty tank shut off switch.
When providing water for a house, water pressure must be created to allow the water to flow inside the pipes. A typical house has 3 bar of pressure, although, as low as 2 bar may be adequate for your needs. Water pressure can be achieved a few ways. Gravity feed is the most basic method; where the water is stored in a tank higher than the house.
If a high storage tank isn’t possible, a smaller booster pump can be added to the solar system to pressurize the pipes. This pump would have to be connected to an additional battery bank to allow pressurizing at any time of day or night. The booster pump technical specs will show the bar capability and how many amps are needed to create the pressure.
Typical Solar Pump Layout Diagram
Solar-powered pumping systems (SPPS) have been utilized for over 20 years.
As photovoltaic (PV) modules become more affordable and the energy efficiency of both the modules and solar-powered pumps increases, SPPS will become a leading technology in remote areas.
SPPS have proven successful in irrigation and livestock watering applications.
There are some problems involved with SPPS that can be avoided with feasibility analysis and proper installation.