What About Water Wells?

Water wells can be a real issue for solar systems.  We have many deep water wells in our area and it's not uncommon to have two or three horsepower pumps.  Pumps have a high "starting surge" because they have to start under load.  This surge can be several times the normal running power required for the pump.  Sooo---the system has to be sized to the start surge of the pump.  What this results in oftentimes is a system that is two or three times the capacity that it would have been without the pump.  That translates to two or three times the cost----you see where this is going.

Smaller pumps are not as difficult or costly, but still need to be calculated carefully for solar applications.

We sometimes use solar well pumps.  Solar pumps don't usually provide enough water flow to be used in the normal pressurized water system, so they trickle water into a storage tank during the day and then a small pressure pump (which our solar system CAN run) provides the proper water pressure and flow for normal use.  Another possibility with this type of storage system is that the tank might be filled occasionally with a generator and a regular 240 volt well pump while the small pressure pump continues to be powered by our solar system.  Here's a typical example.  Let's say we have a 1000 gallon tank and the generator/pump can pump 20 gallons per minute into it.  To fill the empty tank would take approximately one hour (1000/20=50 minutes) and perhaps one gallon of fuel for the generator.  1000 gallons might (if carefully used) take care of a small family for a month, so you could function for a year on 12 gallons of fuel.