Energy Saving Projects
DMU has adopted a strategic target to reduce its carbon emissions by 43% by 2020, from 2005 levels. To achieve this, we will need to make significant reductions in the amount of energy that we use to operate our buildings and communications infrastructure. We must look to reduce the amount of energy that we use, to use energy more efficiently and to reduce the carbon content of the energy that we do use, if we are to meet our targets. For details of energy that we are generating on campus from renewable sources, see ‘Renewable Energy’.
Over the years we have installed a range of equipment that has helped us to provide the same level of service, whilst using less energy. Projects have included: voltage optimisation, boiler load management systems and lighting control systems. In addition, we have an automatic meter reading system that collects data from over 300 electricity, gas and water meters across the campus. We monitor this data to identify any unusual events that could lead to energy wastage.
Here, we describe some of the projects that have taken place at DMU in the last couple of years. Each of these projects is expected to reduce energy consumption sufficiently to payback the investment made within 5 years.
At the Queen Elizabeth II Diamond Jubilee leisure centre, we have invested in two projects that have reduced both electricity and gas consumption. Firstly, a cover for the swimming pool was installed. This reduced DMU’s gas consumption, by reducing the heat lost from the swimming pool water when the pool is not in use. The picture below shows the pool cover being removed from the pool at the start of the day.
Secondly we have installed ‘variable speed drives’ on the pool circulation pumps. The drives will control the speed at which the pumps circulate water around the pool, based on the level of use. Before installation, the pumps were working at 100% capacity, 24 hours a day seven days a week, drawing an electrical load of 15kW. The average load of the pumps since the drives were installed is now just 3.4kW.
The graph below shows the electricity consumption profile of the leisure centre the week before the pumps were installed (red line) overlaid with the consumption profile for the week after the pumps were installed (blue shaded area). The difference in the electricity consumption since the pumps were installed equates to a saving of approximately fifty tonnes of CO2/year and will reduce the electricity bill by £12,000/year.
The pictures above show one of the three variable speed drives that control the pool circulation pumps, and the main controller that samples the pool water to establish the most efficiency pump speed.
LED lighting typically uses approximately 50% of the electricity required by conventional fluorescent lighting. It is ideal in areas where the lighting is used for extended periods of time, or in areas where replacing broken lamps is difficult or costly due to access problems. However, LEDs are much more expensive to purchase and we are therefore targeting their installation into areas that give us the best rate of return, in terms of energy and maintenance cost savings. To date, we have replaced some of the lighting in the Kimberlin Library, Bede Halls of Residence, Estates Services Building, Hawthorn and Portland buildings. In addition, we have replaced external security lighting with LED equivalents, as these are on all night every night, and provide a better light quality.
The pictures below show an LED light, prior to fitting and installation, and a kitchen in one of the DMU halls of residence with LED lights. In the halls of residence, a total of 240 kitchen lights were changed. The previous light fittings used 35W each, whereas the new LED fittings use just 13W each. In total, the new lights are expected to reduce DMU’s CO2 emissions by an estimated 12 tonnes CO2/year, saving DMU over £3,000 and paying back the investment in around 4 years.