BOILERS, PUMPS & VALVES
TACKING PUMP INEFFICIENCY
Today’s pumps are incredibly efficient, but if mistakes are
made in the system design, pump selection or commissioning phases, or if performance cannot be monitored effectively
post-installation, it’s possible to leave thousands of pounds of savings on the table. Peter Wolff, global manager, Ecosystems and Performance Upgrades at Armstrong Fluid Technology, gives some top tips for optimising pump efficiency
in load. Design point and setpoints can be adjusted to match on-site conditions and the pumps are sequenced to operate along their peak efficiency natural curve automatically, for all load conditions. Equipment loading can be optimised across the system as a whole, to achieve significant reductions in energy consumption.
TIP 3: STAGING PUMPS FOR GREATER EFFICIENCY Traditional pump staging strategies turn on the next pump when the existing or current pumps reach 95% of maximum speed. Pumps are typically staged off when the existing or current pumps slow down to 55% of maximum speed. Both of these scenarios (staging pumps on too late, and off too early) involve lost efficiency. The best practice alternative is to adopt efficiency-based staging points (as opposed to staging points based on pump speed). With this control strategy in place, the system ‘surfs’ across the top of the efficiency curves throughout the day, eliminating the wastage inherent in pump speed-based control approaches. This improved strategy can achieve energy savings of over 30%.
TIP 1: EFFECTIVE SIZING At the design and pump selection stage, determine whether the project needs to expand incrementally. For example, is this a district energy network or data centre? If so, selecting pumps designed for the peak output at some future date will build inefficiency into the system from the outset and increase the risk of technical problems. An effective solution is to harness modular design by installing packaged HVAC solutions that facilitate scaling-up, as they are purpose- designed for incremental expansion. For data centre projects, modular packaged systems provide much needed predictability and reliability of environmental performance. For large and complex projects, scalable energy centres and/or temporary energy centres can also avoid the problems of operating over-sized pumps. For pump and system selection on all projects,
look for tools such as AID (Armstrong Integrated Designer), available through ADEPT select software, which simplifies selection and sizing of pumps and accessories, saving time, improving accuracy, and enhancing energy efficiency. The tool enables the creation of comprehensive equipment schedules and system layouts with pre-configured solutions, with the benefit of real-time performance estimates.
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TIP 2: OPERATE PUMPS ALONG THEIR NATURAL CURVE Pumps in variable-speed HVAC systems will typically operate at between 10% and 60% of design flow nearly all of the time. So capacity-based control (which focuses on the equipment being at its most efficient when operating at 100% design flow) fails to harness the full energy and cost saving potential. Demand-based control, by contrast, operates each component at its most efficient point to meet the actual load. Pumps incorporating sensorless control have significant advantages in delivering demand-based control, as they automatically adjust to changing demand whilst reducing system complexity. When a variable frequency drive is added to a HVAC component such as a pump or fan, part-load efficiency can be improved significantly due to the pump affinity laws. If a rotating device is allowed to operate along its peak efficiency natural curve, this can increase operating efficiency by 400%. These efficiency improvements can only be achieved, however, if the pump affinity law relationship between pressure and rotary speed, along the natural curve, is maintained at decreased speeds. The latest generation of intelligent pumps
incorporate on-board inverters, making them capable of adjusting automatically to changes
ENERGY & SUSTAINABILITY SOLUTIONS - Spring 2026
TIP 4: PREVENTING OPERATIONAL DRIFT Operational drift can occur over time, often as a result of adaptations to the system after installation. These issues can now be overcome easily using cloud computing and machine learning. The advanced connectivity of today’s pump models provide the custodian with real time monitoring on browsers or apps, reducing energy costs, improving environmental performance, and predicting potential technical issues, at any stage in the lifecycle of a building. Armstrong Envelope, for example, is an integrated digital platform that delivers optimisation through performance mapping, cutting-edge analytics and lifecycle services. Importantly it can optimise equipment from other manufacturers in addition to Armstrong components. Armstrong’s Envelope Advisor can analyse the HVAC system’s operation effectiveness, air and water side, comparing it with industry standard guidelines, and highlight any issues affecting performance to enable them to be rectified. You don’t have to replace the complete pump
to harness this functionality. Many Armstrong pump models, for example, enable the pump head/rotating assembly to be updated whilst leaving the pump body in place. This reduces cost and disruption for the upgrade of the pump and can unlock significant savings.
Armstrong Fluid Technology T: 0161 223 2223
www.armstrongfluidtechnology.com
www.essmag.co.uk
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