5.0 1 Diurnal energy balance pattern for a sample day

0.0 5.0

10.0 15.0

20.0 25.0

30.0 35.0

1965 1970 1975 1980 1985 1990 1995 2000 2005 Years E n ar g y c o m su n ti o n m il li o n b ar re ls 0.0 10.0

20.0 30.0

40.0 50.0

60.0 70.0

80.0 P u p u la ti o n m il li o n Total final ernergy consumptionpetroleum+electricicty Total consumption of petroleum products Electricity consumption Population million persons operating cost of diesel, two other factors preferring electricity were convenience of operation and oil and tune-up costs of the diesel engine. Figure 1. Energy consumption in agricultural sector and population growth Table 1. Irrigation pumping plant equipment efficiency New 1986 Equipment Attainable efficiency percent Pumps centrifugal, turbine 75-82 Right angle pump drive gear head 95 Automotive-type engines 20-26 Industrial engines Diesel 25-37 Natural gas 24-27 Electric Small 75-85 Large 85-92 Hill 1999 suggested the general ways for reduced energy consumption in irrigation pumping plant including: 1. No pumping – revert to rain fed cropping 2. Pump perform based on water crop water requirements. 3. Evaluate irrigation system 4. Test pump operation 5. Practice flow load management 6. Use low cost energy. Overall pumping plant efficiencies for electrically driven pumps average were 45 to 55 percent based on field testing program in some states of USA, as compared to a attainable efficiency of 72 to 77 percent. This research showed about 25 percent of electrical energy used for pumping was wasted due to poor pumping plant efficiencies alone. some of the more common causes of unsatisfactory performance and their remedies are as follows: 1. Impellers that are out of adjustment. 2. Pump bowls designed for a higher pumping rate 3. Damaged impellers 4. Incorrect power unit selection 5. Failure to perform required maintenance Chavez et al., 2010. In recently years pressurized irrigation systems expand in Iran. For provide pressure these systems consume more energy than gravity systems therefore investigation of efficiency and waste energy at agricultural pumping plant in present situation and promotion ways of energy efficiency is necessary.

2. MATERIAL AND METHODS