Solar water pumping for irrigation and drinking purposes is considered one of the
most recently power system needed. The most important usage of solar pumping systems is to irrigate
the agricultural lands to help farmers instead of using electrical or fuel system that take a lot of time,
high cost, effort and much losses. In this research, the performance evaluation of a mini water pump (5
Watt) powered by small solar photovoltaic (PV) panel (10 Watt) was investigated to supply the needed
water for irrigating roof cultivation units. The experiments were carried out at Faculty of Agriculture,
Zagazig University, Sharkia Governorate, Egypt (Latitude 30.5o – Longitude 31.5o) in winter and
summer seasons of 2018. Two solar pumping systems were evaluated; DC solar pumping system
(DSPS) and AC solar pumping system (ASPS) under different operating parameters of PV panel tilt
angles (15o, 30o, 45o, 60o and 75o), solar radiation hours during daylight (9:00 to 15:00) and pumping
heads (0 ,0.5, 1 and 1.5 m). All parameters were evaluated by determinations of pumping discharge,
hydraulic energy, pump efficiency and cost. The obtained results revealed that, the best PV panel tilt
angle for Zagazig region was 45o and 30o in winter and summer, respectively. Discharges and
pumping efficiencies of ASPS were higher than DSPS. The optimum pumping conditions were 0.25
and 1 m of pumping heads with 220 l/hr., and (83 l/hr., for winter, 88 l/hr., for summer) of pumping
discharge for ASPS and DSPS, respectively. Pumping costs of one cubic meter of water by DSPS at
pumping heads of 0, 0.5, 1 and 1.5 m were (0.16, 0.17, 0.19 and 0.21 LE) and (0.15, 0.17, 0.19 and
0.21 LE), during winter and summer seasons, respectively. While pumping costs of one cubic meter of
water using ASPS were about 0.22, 0.45, 1.23 and 7.11 LE/m3 at the same heads, respectively. So, a
small size of solar PV power system can be efficiently supply irrigation water for roof cultivation units.