Boilers & Burners

OFFSITE FABRICATED HEATING SYSTEM TICKS ALL BOXES FOR SOCIAL HOUSING PROVIDER

Rob Erwood, Sales & Specification Director at Baxi Commercial Solutions, discusses how using an offsite fabricated heating solution helped WDH achieve all its project goals at the Smirthwaite Estate

Refurbishing the heating systems of properties to the required efficiency standards with minimum disruption to residents can be challenging for housing associations. One highly effective approach is to use offsite fabricated heating solutions, as Wakefield & District Housing (WDH) discovered when carrying out a heating refurbishment at the Smirthwaite Estate in Normanton.

The Estate consists of 192 twobedroom maisonettes, 70 three-bedroom houses and 14 one-bedroom bungalows. Previously, three 25-year-old boilers had served two district heating circuits which in turn feed heat interface units (HIUs) within the individual dwellings to provide heating and hot water services.

When the old boilers came to the end of their serviceable life, WDH’s inhouse technical services team installed temporary plant to maintain the service while they evaluated the feasible options.

“We were keen to explore the use of renewable technologies, either to replace or assist new gas-fired boilers,” said Stephen Dumbrell, WDH’s Assistant Mechanical Services Manager. “Given the nature of the existing heating system at Smirthwaite, and therefore the possible limitations, we asked Rob Wilson at Building Services Solutions to carry out an appraisal of the low carbon options.”

The findings of the report ruled out air source heat pumps, ground source heat pumps and biomass as practical alternatives at the estate.

“For a number of reasons – including space constraints, insufficient power supply, noise, the existing distribution system and operating temperatures – these technologies had to be disregarded as viable options,” Rob explained.

Instead, he recommended modular, energy-efficient replacement boilers with a Plate Heat Exchanger (PHE) to deliver long-term improved heating reliability while reducing energy consumption and carbon and NOx emissions.

“This was the most practical, cost-effective and reliable approach to improve outcomes for residents while meeting WDH’s requirements for improved efficiency, minimal disruption and easy future maintenance,” Rob continued.

Rob specified installing eight Remeha Gas 220 Ace 300 in a backto-back arrangement using a Remeha offsite fabricated cascade system with a Plate Heat Exchanger. Remeha is part of Baxi Commercial Solutions.

Working with Rob and WDH, the Baxi Commercial Solutions team prepared CAD and 3D drawings of the boiler cascade arrangement bespoke to the design parameters. In addition to the boilers, the specially sized and integrated pump sets and PHE, the packaged solution includes a pressurisation unit, dosing pot and an expansion vessel.

The detailed drawings provided early visualisation of the layout. Through subsequent collaborative discussions with the group, revisions were considered and implemented to reach a final design that met all the site constraints and requirements. Production took place in a factory environment, with comprehensive end-of-line testing.

The equipment was delivered to site in clearly numbered pallets with a reference drawing for guidance. WDH’s technical services team then bolted the boilers together and connected them to the existing system.

“It is very unusual for an inhouse team to be able to carry out a project of this scale,” said Stephen. “One of the many benefits of using the rig was that it provided a good structure for our engineers. It avoided the need to size all the individual components and, as no welding was required, saved a significant amount of installation time.”

The switch to the new boilers took around four hours, allowing WDH to achieve their key goal for minimal downtime and disruption to residents.

“The plant room has been completely transformed,” Stephen continued. “We now have a very well organised plant room that makes the best use of space and provides good accessibility to all the boilers for future maintenance.”

Commissioning was carried out by Baxi’s commissioning engineers who safety tested the installation in conjunction with the WDH site team and control specialist. The Baxi Commercial Solutions team will also provide WDH’s technical services team with onsite training on the new boilers to ensure ongoing high performance.

WDH are anticipating a considerable reduction in energy consumption from the more efficient equipment and design and further operational cost savings with the removal of expensive breakdown callouts.

Martyn Shaw, Executive Director of Technical Services at WDH, said: “I am extremely proud of what we have achieved. Our teams have gone over and above to overcome a complex issue, showing dedication, innovation and due diligence to get the job done well for our customers.

“The simple fact that the residents at Smirthwaite saw little or no disruption during the transition to the new system, is a testament to the inhouse talent we have at WDH. The system will help us to achieve our aim of creating better, more sustainable places to live.” remeha.co.uk