An Energy-Based Criterion for Selecting Low-Energy-Consumption Centrifugal Pumps

Pumping systems are among the most electrical energy-consuming applications. To improve energy savings in such systems, new efficient pump’s models have been proposed and developed from studies that are mainly focused on the behavior of the internal flow and the optimization of the impeller’s geometrical parameters. However, this useful approach is insufficient to achieve satisfactory and efficient operation and, thus, to guarantee a reduction in the current level of energy consumption in these systems. To achieve this, the pump must not only operate efficiently but also consume low energy. In this paper, a mathematical criterion was developed for selecting low-energy-consumption pumps among pumps previously selected through an efficiency criterion. The analytical solution obtained was implemented in MATLAB®and relies on two databases. The first one comprises information on 52 pumps from different manufacturers and operating ranges and includes numerical coefficients describing the flow rate dependence, Q, on the head, H(Q), shaft power, N(Q), and efficiency, \(\eta (Q)\) $\eta (Q)$ . The second database contains system parameters, such as piping system’s length, diameter, and material, the different tube fittings and accessories, and the information about the suction and discharge reservoirs, e.g., free surface velocity and pressure, and the static heads. Typical residential and commercial systems were considered. The results show that the developed model accurately identifies pumps with the lowest energy consumption for a given system. First, the model identifies efficiently operating pumps. Later, using the low-energy-consumption criterion, it identifies the most energy-saving pumps among those operating efficiently. Finally, a numerical indicator of the energy consumption, defined relative to the pump with the highest value, allows for determining which pump has the lowest consumption. This methodology also facilitates the evaluation and understanding of why inefficient pumps may have low energy consumption, thus providing a rationale for their exclusion.