poster - International Conference of Agricultural Engineering

Pressure: it was obtained by means of two pressure gauges. One gauge was installed
in the suction circuit, and the other was placed in the discharge circuit. Value ranges
were between 0-6 and 0-10 bars, respectively.
These measurement instruments are required to be installed in the pump in a representative
measurement period (e.g. during the crop highest water demand period). In this study,
instruments were installed from March 16th to 23rd of 2011. Although the period in which the
measurements were obtained did not coincide with the maximum demand period of the
installation, it permitted to compare the demand measured in situ (by using the measurement
instruments) with its electric bill. For this purpose, the electric bills of the irrigation station
along the 2010-2011 season were compiled, what made possible to study its evolution and
possibilities of improvement. In this comparison, the electricity and irrigation water
consumption parameters were contrasted, taking into account the water consumption
estimations and the irrigation calendars for every plot of the studied farm. These data were
supplied by the managing enterprise of the farm.
Some of the more representative indicators of the WUA were calculated. Finally, from
calculated indicators and obtained measurements, some corrective actions to improve the
energy efficiency of the system were proposed and valued financially and energetically.
3. Results
Descriptive
Performance
Efficiency
TABLE 1. Indicators applied to the case study irrigation system.
Value in the
Indicators
irrigation
station
Irrigated area (Sr, ha) 98.93
Annual irrigation water supply per unit irrigated area (V TSr, m 3·ha -1 ) 3,480
Total annual volume of irrigation water supply (V T, m 3 ) 344,277
Maximum total contracted active energy (kWh) 19.8
Annual consumed active energy (Eac, kWh) 68,123
Annual consumed reactive energy (Er, kVArh) 36,802
Power Factor (FP) 0.89
Consumed Energy per unit irrigated area (kWh·ha-1) 688.60
Consumed active Energy per unit irrigated area (EacSa, kWh·ha -1 ) 681.27
Consumed active energy per unit irrigation delivery (EacV T, kWh·m -3 ) 0.20
Energy cost per unit irrigated area (CENSr, €·ha -1 ) 123.07
Energy load index (ICE, m) 56.7
Average energy efficiency of the pumping system (EEB, %) 55.6
Efficiency of the energy supply (ESE, %) 91.2
General energy efficiency (EEG, %) 50.7
The main energy efficiency indicators that were obtained in this study for the 2010-2011
season are presented in Table 1. These indicators coincide with the ones used for collective
irrigation systems that, with some peculiarities, can be also extended to individual irrigation
systems. Energy consumption data used in this study included only from June of 2010 to
March of 2011 (Table 2), being considered as representatives of a full year. Water
consumption data along the irrigation season of lettuce crops began in December of 2009
(first seedlings grown) and finished in April of 2010. The next season began again in
September of 2010 in order to finish in April of 2011 (see Table 2). For this reason, only a
simultaneous comparison of water and energy consumption data from October of 2010 to
March of 2011 was able to be performed. In this study it has been taken into account that
irrigation water consumption between May and September is low or inexistent.
Total annual volume of irrigation water supply has been obtained from seasonal irrigation
water consumption data. These data have not been contrasted with in situ values because,
-1
in this case, no devices were available for that purpose. The calculated value of 3,480 m
3·ha
is an estimated average value obtained from the average consumption of lettuce in the
studied farm according to the estimated data provided by the management enterprise.