Making pumps more energy efficient

06 February 2023

Around 16% of a typical industrial facility’s electricity costs are generated by its pumping systems. Find out how to reduce this figure.

With energy prices continuing to rise, many food processors will be finding their pumps becoming even more expensive to run. However, there are savings to be made. Castle Pumps offers some advice on how to optimise energy consumption of pumps – whether for new or existing pumps.

Avoid oversizing: Oversizing the pump is common to cater for any uncertainties of the duty required in the design process for example when the exact viscosity of a sauce is unknown. However, as a higher performance in terms of flow and pressure requires the motor to run at a higher power, an oversized pump uses more energy than necessary. For that reason, it is important to select a pump that can be run as close to its Best Efficiency Point as possible.

Variable frequency drives (VFDs): The purpose of a VFD is to vary the speed of the motor to achieve the application’s actual performance requirements, as opposed to the maximum that the pump can provide, therefore reducing energy waste. They are usually used to slow oversized pumps or where there are differing duty requirements i.e. sometimes it may need to operate at full speed while at other times it does not. For example, where the same pump is responsible for filling a small barrel with wine and also tank to tank bulk transfer.

Parallel pumping systems: When the occasional duty requirements are significantly higher than the standard operating conditions, a single pump could be operating far from its Best Efficiency Point for much of the time. By installing a second smaller pump to meet the average system requirements, the larger, higher energy consuming pump would only need to be used when it warrants it.

Limit pipework pressure loss: The power of the pump required needs to account for pipework pressure loss, so bends and changes in the size of the pipework should be kept to a minimum. Whilst food production requires pipework to be regularly cleaned and free of corrosion and rust, this can result in pressure loss, which means cleaning and maintenance of pipework is vital.

Install control features: Pumps are often in operation when they are not actually doing anything, due to lack of control. Control systems, such as pump timers, batch meters and level switches can be implemented to shut down a pump when it is not in use. For example, once the required volume of ingredient is dosed into a mixture, or once a container being filled of product is full.

Carry out maintenance: Like any equipment, wear can reduce efficiency. The energy efficiency of a pump can degrade as much as 10-25% before it is replaced, making routine maintenance critical. For example, leakages mean that more power is required to produce the same flow, making wear ring replacement even more vital.