The electrical performance of the PV modules can be severely affected by operating temperature of silicon cells due to properties of the crystalline silicon used; the energy generated from these cells decreases with their high temperatures. To reduce this decline in energy, the PV modules use cooling water by placing a tube containing many regular holes on the top end of the module, and water flows on the surface freely in several flows. So, with flow rate (4.224 l/min.m2), module temperature decreases up to (20C°); the record of increased value of electrical yield over the whole day is about (12.8%). and efficiency rises (from 8.31% to 9.62%) of (1.31%). With Flow rate (3.167 l/min.m2), temperature of module decreases up to (18C°); the record of increased value of electrical yield is about (9.8%), and efficiency rises by (1.03%). But with flow rate (2.112 l/min.m2), temperature of module decreases up to (15.5C°); the record of increased value of electrical yield is about (7.8%), and efficiency rises by (0.83%). Furthermore, flow of water on the surface of PV module reduces the reflection losses because the refractive index of water with (1.3) is intermediate between air (1) and glass (1.5). In addition, the surface of module remains clean.