23/06/14 Council takes the plunge and saves £60k on energy costs with EMIR User the Central Group and ABB drives
Liverpool City Council is saving £60,000 a year on energy costs at five of its swimming pools following the installation of ABB variable-speed drives on filtration pumps and air handling units. Faced with rising energy costs and the need to trim budgets, the council approached ABB authorised value provider Central Group for help in cutting the energy use at its swimming pools. The council’s maintenance manager says: “We had an energy conservation report done on one of our pools by an independent company which had recommended ABB variable-speed drives.” Central Group investigated the pumping set up at the swimming pool. The two filtration pumps were originally run in a duty/standby configuration. Pumping rates were increased as more people entered the pool. Central suggested using the pumps in a parallel pumping scheme that would cut energy use. Gianfranco Colangeli of Central says: “At first the council was sceptical of the proposed scheme. We suggested a trial to prove that it could work and they agreed. “We logged the energy use of the pumps beforehand - we then installed two new ABB drives. Our predictions indicated a 10-15 percent saving, but logging the energy use we found that the drives made a 35 percent saving, with a payback of around six months. This was all with no change in the flow rate or water pressure.” Following the installation of the permanent drives, Central Group also installed low occupancy switches, which cause the drives to run the motors at even lower speeds when few people are using the pool or when the pool is closed. “We had budgeted for 45 Hz,” says Colangeli, “but we can go as low as 30 Hz.”
Since the initial installation, ABB drives have been retrofitted into four other swimming pools, for water pumps and air handling units. With a total of 20 drives over the five sites ranging from 7.5 to 18 kW, the project is saving £60,000 a year, with a payback of around two years.