A research on energy saving possibilities with variable speed pumps in pressurized irrigation systems

Many of the irrigation pumping stations cannot be operated due to high energy costs resulting from design mistakes or when operated they bring about high running costs. In this study, energy saving possibilities were analysed in a pumping station serving two different pressurized irrigation networks and a model to save provide energy savings was developed. The model is aimed to optimize energy consumption by matching pump and system characteristic curves during the whole irrigation season. For this purpose, current situation of the pumping plant was investigated by evaluating pump and irrigation system as a whole. By optimizing the system with the help of the methodology developed, the quantity of energy savings respect to classical approach was determined under different scenarios based on variable speed technologies. In addition, overall efficiency of the pumping station and the specific energy of the alternatives examined were calculated, the economic analysis was carried out. The adaption of pumping characteristic curves to irrigation system curves is possible with pumping stations having variable speed technologies. Therefore, simulation tools and variable speed technologies approach were used in combination. It was concluded that in comparison with the current constant speed operation, annual energy savings of about 12%, 15% and 30.3% may be achieved at the pumping station under three scenarios. It was demonstrated that specific energy consumption can be decreased from 0.4591 kWh m-3 to 0,2835 kWh m-3 and from 0.3956 kWh m-3 to 0.3076 kWh m-3 in M-1 and M-2 irrigation systems respectively.All the results and economic analyses showed that the presented methodology is efficient in terms of energy savings and applicable in terms of economics.