How do you size a solar pump?
Sizing for a solar pump is dependent on your Total Dynamic Head. The Total Dynamic Head calculated from your project will dictate which solar pump is the best fit for you. Total Head will also determine the necessary performance needed from a pump in order to mee your water needs. Every project is different and will have varying factors that affect Total Dynamic Head. There are a few factors required to calculate your Total Head. Pumping head is the maximum height that a pump can move fluid against gravity, and it determines the various head loss that the pump must overcome. To calculate total dynamic head you will need the following: your static water level, drawdown, additional vertical lift, and any frictional losses in the pipe are added together.
Static Water Level: A recent well survey will typically list your Static Water Level. It is the distance from land surface to the water in the well. -Drawdown: When the Static Water Level drops due to pumping, drought, etc., wells producing less that 5 gallons per minute will need to consider drawdown. The less gallons per minute the more potential drawdown you may have. Drawdown is the change in groundwater levels.
Additional Lift: The additional lift is an estimate of the elevation at your well head to the source you will be pumping into. The difference between the two elevations is the additional vertical lift you will add to your Total Dynamic Head.
Frictional Loss: The higher the Gallons Per Minute you have and the narrower the pipe, the more frictional loss will occur. That means more head on the pump and less flow at the outlet. Sizing you pipe up will help decrease the Frictional Losses.