example 15.6   
 energy needed o pump water every day 3.406250kWh/day 
 overall efficiency 0.34 
 energy output of pv system 10kWh/day 
 annual energy out of array 10Wh/Wp 
daily energy output of array 5.479Wh/Wp 
 peak wattage of pv array 1825.00Wp 
 rms output voltage 222.14V
number of modules in series 13 
 rated peak power output of each string 520.00W 
 number of strings in parallel 4