Keeping control of electric heating costs
April 1st 2008

For buildings still using electricity for space and water heating, robust easy-tooperate energy management systems such as the Ambiflex MF620 and MF820 can help to reduce energy costs and cut emissions, as Fife Council has discovered

In the past, Fife has been a major coal-producing region. In the 1960s, with coal stations forming the backbone of UK power generation and prices relatively low, Fife Council chose electricity as the preferred heat source for its municipal buildings and schools.Times have now changed and electricity is no longer the cheap energy source it was just a few decades ago.Yet today, a number of publicly-owned buildings in Fife remain electrically heated.

With rising prices, the Council began a review in early 2006 to identify ways of reducing costs and cutting carbon emissions. It identified some of the major energy consumers and produced a priority list of actions and locations, which included a number of primary schools.A key element in the programme was the implementation of a central energy management system.

The energy management system chosen by Fife Council was supplied by Ambiflex, the Cheshire-based manufacturer of building management systems.A combination of MF620 and MF820 controllers have now been installed at 37 sites.These are networked using the company's Ambilink software to the Council Energy Management Department via ethernet connection.

However, there is a facility at each location for temporary local override of the settings, to take account of special events like parents'evenings, and so on.

In the schools, a set of heating distribution panels are connected to an electrical contactor and this forms a heating 'zone'. A temperature sensor is installed in each zone. In addition, a further sensor is fitted to the exterior of each building to track outside air temperature.

The electricity tariffs negotiated by Fife Council include peak and offpeak periods. In order to keep costs as low as possible, cheaper off-peak electricity is used to charge the panels overnight in order to maintained optimum temperature during the hours the school is in use.

This means that the controller has to measure outside temperature, compare it with the internal conditions and calculate how many hours of charge are needed prior to the changeover to peak rate at 7.30am. If the temperature in any zone drops below the required level during the day, this is detected by the temperature sensors and that zone receives a heating boost – up to two, of 1.5 hours duration each.

Fife Council has carried out an assessment of the effectiveness of the energy management systems.

The annual consumption to March 2005 and to March 2006 was 16,793,111kWh and 17,099,974kWh respectively, giving an average pre- Ambiflex consumption of 16,946,543kWh.The consumption to the end of March 2007 was 15,269,657kWh showing a saving of 1,676,886kWh.This represents a 10% reduction.Taking an average cost of 7 pence per kWh for all the sites, this amounts to a cost saving of £117,382 over the year and a payback of 1.57 years.

"We had the option to choose between a number of different manufacturers,"explains Fife Energy Officer Forbes Reid."The Ambiflex system provided value for money, it was simple to operate and the design indicated it could do the task we required.The speed and quality of the Ambiflex service was also a key factor.The value for money we have achieved from our investment decision has now been clearly demonstrated."