Seven years on from the first installation for Lincolnshire County Council, Sabien Technology’s M2G boiler load optimisation controllers continue to deliver energy savings in line with those predicted at the time of specification.

The M2Gs were installed during two programmes, primarily to prevent wasteful boiler dry cycling. The first programme saw 87 units installed on boilers across 23 Council properties, including Council offices, residential homes, libraries and registry offices. CUSUM analysis at three sites showed weighted average savings in gas consumption of 15%.

Having proven the technology, the Council decided to extend the use of M2G, installing 1,100 units in a range of primary and secondary schools. On completion of the school’s project, the Council then undertook further measurement and verification of energy savings.

“We carried out further CUSUM analysis following the school project, comparing fuel consumption with the same period the previous year and correcting the results using degree day data. The average savings across all the schools that were assessed was 9.1%, though some were as high as 30%”, recalled the Council’s Senior Sustainability Officer Steve Golightly.

“We supplied the equipment to the schools at no charge, and they were able to keep all of the savings, so the M2G installation has effectively freed up funds for them to use in other areas,” he added.

In most cases, the highest savings have been achieved during spring and autumn when boilers are running for longer periods at part-load and boiler dry cycling is most likely to occur. In some cases, though, the Council also measured savings as high as 20% in winter.

“When we investigated this further, we found these were smaller schools with a single, over-sized boiler. Because the boilers were over-sized they were also running at part-load, and dry cycling, through the winter. Installation of M2G prevented this energy wastage, which accounts for the winter savings,” Steve Golightly explained.

Most boilers in the Council’s school estate were already fitted with relatively simple controllers providing timed control and weather compensation, though some larger schools have building management systems (BMS). In all cases, the M2G units have worked in harmony with existing controls to increase the energy savings that are being achieved.

“The M2Gs that we first installed have now been running for seven years; without any issues, they are all still working well and we have not had any problems with ambient temperature control. So, we are very pleased with the investment we have made in M2G and when we visit sites in the County to advise on energy savings, M2G is one of the first things I recommend,” Steve Golightly concluded.