R K District Heating Limited, which offers in-house district heating network design services was tasked with planning the pump house for the Blackburn Meadows district heating scheme and had a number of priorities. The pumping requirements on the site are complex and involve handling water at high maximum temperatures (up to around 115°C). The plant needs to offer high levels of energy efficiency across a wide range of operating conditions and the demanding timescales for the project meant that the equipment needed to be installed within shorter than average lead times.

 

Armstrong's 4300 Series pumps in action at Blackburn Meadows.

 
IPS4000 pump controller
 
The company chosen to supply the integrated pump solution was Armstrong Fluid Technology – a manufacturer of packaged pump solutions and integrated plantrooms with extensive experience of biomass-based systems. At the heart of the system are six Armstrong 4300 DE variable speed pumps integrated with Armstrong's IPS4000 pump controller. The variable speed pumps incorporate on-board inverters which enable them to respond instantaneously and automatically to changing requirements, adjusting their motor speeds and drawing only the power required to meet the load. As they are Armstrong DE (Design Envelope) models, they also provide energy efficient operation and flexibility to adapt in the future without the need for replacement or system over-sizing.

Balancing supply
 
The pumps are controlled by the Armstrong IPS4000 which calculates how best to meet demand and automatically manages pump operation accordingly. The IPS4000's advanced control technology ensures that pumps are operated at their most efficient point at all times, and are phased in and out in the best possible configurations to deliver the required capacity. By treating the system holistically, and balancing supply across all six pumps, the IPS4000 is able to achieve high levels of efficiency.
 
As the biomass-based district heating scheme has a particularly wide range of operating scenarios, the advanced control made possible by the IPS4000 ensures that energy efficiency is optimised whatever variations may occur. In the future, as additional plant rooms across the Sheffield area are integrated with the district heating scheme, the IPS4000 will ensure that the pumps adapt to accommodate the changing requirements whilst still maintaining optimum energy efficiency.

Off-site assembly
 
The specification of integrated pump solutions from Armstrong Fluid Technology also had significant advantages, as they were assembled, integrated and tested off-site, at Armstrong's purpose designed factory in Halesowen. The completed pump solution was supplied to site ready-assembled and only required final connection. Off-site manufacture ensured that all components for the pump solutions were connected and integrated exactly as required, maximising control over the final quality of the systems and ruling out the risk of errors. Using this approach, the timescales for delivery of the project were also reduced significantly, with assembly of the packaged plant able to progress concurrently with on-site construction, unaffected by adverse weather or other potential delays.
 
A number of practical benefits were also provided by the Armstrong integrated pump solution. The pumps are designed to be an integral component of the pipework, eliminating the need for inertia bases, springs, flexible pipe connectors, field grouting and alignment. This provides a tidier, easier to access pump room, whilst the dynamically balanced impeller, and the shaft assembly rotating vertically on the pump centreline provides quiet, long lasting operation with minimum vibration. The pumps also feature space-saving Suction Guides and FloTrex valves which reduce the requirement for pipework and fittings, and perform multiple functions with a single component.
 
David Forrest, Project Manager at R K District Heating said: “The pump house for the Blackburn Meadows district heating scheme was a complex and challenging project, so it was crucial to put together the best possible team to deliver it.” He added: “All parties involved in the project, including Matrix and NIS Insulations, as well as Armstrong, worked together effectively and this enabled us to reduce the project timescales by around six weeks.”
 
Mr. Forrest said that the control technology of the Armstrong pumps means there is very little need for supervision or intervention by engineers. The neat design means that high standards of presentation are maintained in the pump house and, despite the scale of the scheme, the lack of vibration and noise means that this is a pleasant area for engineers and the many visitors who come to the site.

 

Wayne Kuczer, Armstrong Fluid Technology's area sales manager for the north of England said: “We were delighted to be involved in such a prestigious project. Pump control technology is crucial in a project of this complexity to ensure that the equipment operates to its full potential, and our IPS4000 is excelling in this application.”
 
Design envelope IVS 4300.