District Heating Water Supply Pump Station
The client was concerned about their increasing energy bill. The station provides hot water, for heating, to a district with over 3000 homes.
The station has 4 pumps, all of the same type and all fitted with variable speed drives. The duty flow is 1350 m3/h, duty head of 143 m and a power rating of 745 kW.
The station manager is very keen to reduce operational costs and has expressed a willingness to change operating practices to achieve the energy reduction.
The pipework is warped with insulation so it wasn’t practical to fit any more sensors. It was decided that the station sensors would be checked and then used to complete the pump performance tests.
The station was equipped with flow meters, pressure sensors, power meters and speed sensors. All the signals from these sensors were recorded by the station SCADA system.
The station manager provided 12 months of historic data to help Thermancy engineers to better understand pumping operations at the station.
17% drop in pump efficiency from BEP
Pump speed turned down to 1000rpm, resulting in pump efficiencies as low as 10%.
The data indicated that the best efficiency point (BEP) of the worst performing pump was at 17.4%, with other pumps down 10.3%, 9.8%, 7.6%.
In the summer period, it was noticed that the pump speed was turned down to around 1000rpm, causing the pump efficiency to drop to around 10%.
By refurbing pump C (the worst performing pump) and by increasing the pump speed, the station energy bill has come down by over 16%.