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National Grid upgrade from Armstrong Fluid Technology

A recent energy upgrade carried out by Armstrong Fluid Technology for the National Grid in Solihull, UK, reduced pump energy consumption by more than a third.

Armstrong Tango Design Envelope parallel pumping solutions.

Armstrong pumps were installed to replace six sets of twin-headed pumps that were 16 years old. A new Tango parallel pumping solution installed on the heating system reduced energy consumption by 42 per cent.

In addition to the improvements in environmental performance, the installation of the off-site manufactured Armstrong Tango solution made it possible for the pumps to be replaced over the weekend, reducing disruption for building occupants. Throughout their lifetimes, the advanced control, performance management features, and innovative design of the pumps will reduce the time and costs involved in routine maintenance, providing both best installed cost and best life-cycle costs.

Project overview

The energy upgrade project was carried out at National Grid’s three-storey commercial office block in Solihull, Birmingham. Priorities included the need to reduce energy costs and improve environmental performance of the building. As the workforce of around 200 staff were to continue to work in the building for six days per week throughout the energy upgrade, it was also important that the pump replacement could be carried out with the minimum disruption to daily routine and productivity.

The pumps to be replaced were Holden and Brooke (Armstrong legacy) models manufactured in 2002. Six sets of twin-headed pumps were removed in total. Three were supplying chilled water (one primary and two secondary) for air conditioning, whilst the remainder were supplying the heating system and domestic hot water requirements. The pumps removed from the site ranged in size from 7.5kW to 37kW.

Recycling of old pumps

The materials used in the construction of Armstrong pumps can be recycled at the end of the product’s useful life with the help of a specialist sustainable disposal company. In the energy upgrade project for National Grid, the legacy Armstrong pumps were disassembled and the materials were separated, enabling them to be recycled.

During the course of the upgrade project, 3.5 tonnes of equipment were removed from the site and a Certificate of Sustainable Disposal was provided to the National Grid. Funds resulting from the sale of the recycled materials are contributed to Armstrong’s allotted charitable causes, as part of its environmental sustainability initiative – Planet Proposition.

Equipment solution

The new pumps selected for installation were Armstrong Tango Design Envelope parallel pumping solutions. The recently-launched Armstrong Tango range offers high levels of efficiency, with built-in parallel sensorless pump control, motor efficiency exceeding IE4, embedded intelligence and connectivity, and innovative design for ease of maintenance. These capabilities, when combined, typically deliver energy savings of more than 30 per cent, significantly improving life-cycle costs.

Designed for all variable speed operation, the Armstrong Tango solutions are fully-integrated parallel pumping modules offering significant reductions in size and weight, and improved efficiency, with particular advantages for applications where full duty standby would traditionally be installed.

Each Tango solution features two pump heads with built-in parallel sensorless pump control integrated as standard. This optimises hydraulic performance, providing three per cent to six per cent improvement in efficiency. In addition, the iECM permanent magnet motors, with higher RPM and integrated drive and controls, deliver levels of energy efficiency in advance of IE4, providing another two per cent to seven per cent efficiency improvement.

Most importantly, the Armstrong Tango range offers a replacement for traditional full duty standby pump configurations in that the optional blanking plate enables on-going single pump operation during servicing and maintenance, with automatic optimisation of energy efficiency.


The Design Envelope performance characteristics of the replacement Armstrong Tango pump solution made it possible for legacy 7.5kW to 15kW twin headed pumps at the National Grid site to be replaced by smaller 5.5kW to 7.5kW models with integral inverters. This provided an opportunity to reduce the embedded carbon related to the project, as well as reducing physical footprint to free up space in the plant room.

A Tango parallel pumping solution, installed as part of the energy upgrade, was closely monitored to analyse potential energy reductions within a range of different operational scenarios. Average kWh/h of the legacy pumps in the week prior to retrofit was 10.79.

After retrofitting, the replacement Tango solution was monitored for a week (prior to commissioning) to provide a baseline measurement of energy consumption. This revealed that the Tango pump reduced average kWh/h from 10.79 to 10.2. The Tango parallel pumping solution was then commissioned to demonstrate its full pump performance characteristics. This resulted in a significant further reduction in energy consumption, with average kWh/h dropping down to 6.26. This demonstrated a 42 per cent reduction overall in average kWh/h as a result of replacing the legacy pumps with the Tango solution.

Pump management and after sales service

Achieving optimised operation of the pumps is greatly assisted by Armstrong’s Pump Manager - a web-based service that leverages the embedded intelligence and connectivity available in its Design Envelope pumps to provide sustained performance and significantly enhanced reliability. Delivered as a secure, Cloud-based application, it provides wireless connectivity and a host of on-board web services as standard.


Going forward, all pairs of pumps have now been commissioned to operate at their most efficient. For this energy upgrade in a three-storey office block, energy savings are expected to be in the region of 30 per cent and 45 per cent for each pair of pumps, delivering significant reductions in utilities bills for the building owner. Other benefits arising from the choice of Armstrong Tango parallel pumping solutions include, reduced embedded carbon, smaller physical footprint, enhanced maintenance and improved reliability, resulting in lower life-cycle costs.

13 November 2019


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