A key element of Marks & Spencer’s carbon reduction and sustainability strategy is an estate-wide energy efficiency programme. The retailer has worked closely with control and monitoring specialist RDM over many years, developing its approach into one of the most advanced and successful in the retail industry.
New Ways of Reducing Energy Use
Having successfully adopted many major energy saving technologies and practices, the challenge is always to identify new ways of reducing energy use, so that progress in cutting emissions can be maintained and the company’s stretching targets achieved.
A potentially promising area identified was to harness the ability of RDM control systems to optimise suction pressure on the many hundreds of refrigeration packs operating in the retailer’s stores across the country.
Suction pressure optimisation involves allowing RDM pack controllers to offset the target suction pressure in response to fluctuations in cooling load. This more closely aligns the performance of the refrigeration system to actual demand, improving efficiency without sacrificing the performance of store systems.
To take full advantage of the energy saving opportunity, the retailer simply had to apply software updates. They also choose to re-commissioned refrigeration plant across its whole estate, to ensure the base condition of equipment was tip-top.
Performance and Quality Requirements Had to Be Met
The work focussed on HFC refrigerant-based systems, as CO2-based cascade systems inherently allow suction pressure to float in response to cooling demand.
In addition to working with RDM, M&S collaborated with specialist energy consultants. A key focus was on trials to establish the most effective configuration for optimising plant, to ensure that all performance and quality requirements continued to be met.
Multiple regression analysis was carried out to precisely determine the savings that could be attributed to the initiative. The analysis was verified by specialists at Reading University statistical services centre, who authenticated the results.
Abbey Design Associates re-commissioned and configured the RDM pack controls and Data Manager front end systems across the retailer’s estate. RDM remotely upgraded all pack controller software to the latest versions, to ensure optimisation was as effective as possible.
AB Group carried out site-by-site, system-by-system investigation and improvement works, to maximise the savings. Using RDM’s latest monitoring systems, the retailer was able to identify systems that were under-performing. AB Group then visited the stores identified, to locate the problematic equipment and resolve issues
RDM created bespoke reports which enabled M&S to identify where further work was needed in order to optimise store equipment. Work could be as minor as replacing a faulty probe, through to a more complex plant-wide issue requiring more detailed investigation.
All work carried out was logged and reported back to M&S’s FM teams, ensuring that learnings were carried forward and integrated into the company’s maintenance programme.
What Has Been the Impact of the Programme?
Analysis to date indicates a potential annual saving of 4 to 5% on refrigeration pack energy consumption. This equates to a reduction of over 1000tonnes CO2e and offers a payback on investment of less than a year.
The partners say that they are confident that, through further testing and refinement, they can further develop the initiative, increasing energy savings and reducing carbon emissions further.
About Resource Data Management
Resource Data Management (RDM) is a global energy and building controls specialist who are trusted to provide customised HVACR and BEMS solutions to the world’s leading companies.
RDM energy solutions provide retailers, contractors and facilities management companies with access to real-time performance data giving businesses full control over energy use.