We were pleased to be informed that Sainsbury’s Crayford, one of our many Sainsbury’s projects undertaken for Halsall Electrical last year had been nominated for RAC award in the category “Collaboration of the year” award.
The proposal to extend the existing SSL Sainsbury’s store at Crayford from and existing 35,000 sq.ft store to a gross area approaching 100,000 sq. ft. was always going to be challenging and local planning authority pressure enabled Sainsbury’s Stores Ltd to look toward new technology to solve their problems. The innovative solution of using a Ground Source Heat Pump (GSHP) system was fraught with possible problems, not least getting an aggressive retail construction team to lower their guard and work together to drive through un-explored engineering territory without resorting to the usual methods of divide and conquer.
The Main contractor, though taking management responsibility made the wise decision to actually back off and let the services team work directly with the Ground source system Provider to resolve issues without much need for authoritative instruction / intervention.
The team were just told to “get it done, make it work, complete on time”. The physical constraints of the site with demolition on one side, part operating store on another, an operating greyhound stadium next door and Overhead high voltage cables less than 10m above the roof top plant were as nothing compared to the political limitations imposed by ever changing boundaries of contractual responsibility.
Halsall and RED (as their Mechanical consultants) took the co-ordination lead helping the GSHP provider to integrate with the team, RED chaired meetings at their London Office as well as attending site based meetings. RED worked very closely with Greenfield Energy the GSHP provider through many incarnations of schematic layouts until the system was finally concluded.
The GSHP system provides water-based cooling to the CO2 refrigeration packs, for a saving of 20% of total store refrigeration energy compared to latest standard air-cooled options. The same system supplies ground source heat pumps which, boosted by the captured waste heat of rejection from refrigeration, are delivering space heating, cooling and hot water at average energy savings of 80% while replacing gas with electricity.
The closed-loop system also ensures limited water use (e.g., compared to an open-loop system), and minimal environmental impact. This was highlighted positively in the Environment Agency and Thames Water responses to consultations which were, unusually, required in Crayford’s case as the site lies within the most sensitive ‘Zone 1’ for water protection.
The system has been running close on a year now and the installation has proved so successful that we are working on 2 more systems of similar size with the same team this year.
The 100,000 sq. ft. store has carbon emissions less than the original 35,000 sq. ft. store, eliminating the use of Gas altogether and representing a 60% saving against a 2006 Benchmark Store. All the Energy performance targets specified pre construction has been met this year.