Most of the pumps are fitted with a 2. 7 kW systems can deliver about 124,000 liters of water/day from a total of 50 meters setoff head and 70 meters dynamic head. . This solar water pump up to 3. Solar-powered pumps run on electricity generated by photovoltaic (PV) panels or the radiated thermal energy available from collected sunlight as opposed to grid electricity- or diesel-run water pumps. [1] Generally, solar-powered pumps. . To determine the kilowatt rating of a solar circulation pump, one must consider several influential factors. The application purpose significantly matters, since residential systems. . Once the parameters are known, the power requirements (P) in kilowatts (kW) can be calculated using the following formula: “' P = (Flow Rate Head Height Specific Gravity of Water) / (System Efficiency 1000) + Pipe Friction Loss “' Specific Gravity of Water: 1000 kg/m³ Units: Flow Rate (m³/h), Head. . How much water do you need per day? (Measured in Gallons per Day or Liters per Day). It's the total vertical distance you need to lift the water, plus any friction loss from the length of the pipe. This calculation assumes 100% efficiency; for example, at 90% efficiency, the power needed equates to 83.