pumping systems

A pump’s efficiency can degrade as much as 10% to 25% before it is replaced, according to a study of industrial facilities commissioned by the U.S. Department of Energy (DOE), and efficiencies of 50% to 60% or lower are quite common. However, because these inefficiencies are not readily apparent, opportunities to save energy by repairing or replacing components and optimizing systems are often overlooked.

Define Pumping System Efficiency

System efficiency incorporates the efficiencies of the pump,...

Overview 

Centrifugal pumps handle high flow rates, provide smooth, non pulsating delivery, and regulate the flow rate over a wide range without damaging the pump. Centrifugal pumps have few moving parts, and the wear caused by normal operation is minimal. They are also compact and easily disassembled for maintenance. The design of an efficient pumping system depends on relationships between fluid flow rate, piping layout, control methodology, and pump selection. Before a centrifugal pump is selected,...

Every industrial facility has a piping network that carries water or other fluids. According to the U.S. Department of Energy (DOE), 16% of a typical facility’s electricity costs are for its pumping systems. 

The power consumed to overcome the static head in a pumping system varies linearly with flow, and very little can be done to reduce the static component of the system requirement. However, there are several energy- and money-saving opportunities to reduce the power required to overcome the...

Understanding Your Pumping System Requirements 

Pumps transfer liquids from one point to another by converting mechanical energy from a rotating impeller into pressure energy (head). The pressure applied to the liquid forces the fluid to flow at the required rate and to overcome friction (or head) losses in piping, valves, fittings, and process equipment. The pumping system designer must consider fluid properties, determine end use requirements, and understand environmental conditions. Pumping applications...

Effective pump maintenance allows industrial plants to keep pumps operating well, to detect problems in time to schedule repairs, and to avoid early pump failures. Regular maintenance also reveals deteriorations in efficiency and capacity, which can occur long before a pump fails. Wear ring and rotor erosions, for example, can be costly problems that reduce wire-to-water efficiency by 10% or more. 

The amount of attention given to maintenance depends on how important a system is to a plant’s operations...

In the United States, more than 2.4 million pumps, which consume more than 142 billion kWh annually, are used in industrial manufacturing processes. At an electricity cost of 5 cents per kWh, energy used for fluids transport costs more than $7.1 billion per year. Even one pump can consume substantial energy. A continuously operated centrifugal pump driven by a fully loaded 100-horsepower motor requires 726,000 kWh per year. This costs more than $36,000, assuming average electricity costs of 5 cents...

In pumping applications with variable flow rate requirements, adjustable speed drives (ASDs) are an efficient control alternative to throttling or bypass methods. ASDs save energy by varying the pump’s rotational speed. In centrifugal pumping applications with no static lift, power requirements vary, as the cube of the pump speed and small decreases in speed or flow rate can significantly reduce energy use. For example, reducing the speed (flow rate) by 20% can lower input power requirements by approximately...