Grundfos system optimises water distribution

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Need to reduce leaks, save on energy costs while meeting the fluctuations in water demand? The Grundfos Demand Driven Distribution solution will deliver against all three of these challenges…

The demand for clean and safe drinking water continues to grow and this is a major challenge as we need to maintain these precious resources in the best way possible. One of the major obstacles to achieving this means we need to get much smarter about managing water and in particular tackling leakages. For instance in London, 1,000 million litres of clean water are lost every day while globally this figure is estimated at 45 million m3 per day, enough to serve 200 million people.

Today Grundfos can put forward a solution to this problem via a process called Demand Driven Distribution (DDD). This system uses pressure control to deliver against demand this means that in high flow periods, friction loss in the mains is relatively high and any corresponding losses are therefore low. However, when this demand decreases and the flow is maintained, this leads to additional water loss in these off-peak periods. The benefits of using the DDD system helps to manage these changes in demand meaning a leakage reduction of approx. 20%.

What is DDD?

The Grundfos DDD system achieves this by automatically adapting the setpoint to match the actual flow, in order to meet the actual demand that exists within the system. This solution is unique to Grundfos’ DDD controller and has been made possible because the MPC controller has been specifically designed and programmed to achieve this task. 

This controller actually addresses this issue in two ways, firstly by reducing surplus water pressure in pipes and secondly it also lowers the risk of water hammer, which is a primary cause of new pipework weaknesses. This multi-pump solution operates at proportional pressure and this ensures flow is supplied precisely as is needed and at the required pressure.

Additionally, the controller will work with all types of pumps, as well as delivering significant water leakage savings, its high-efficiency motors can also markedly reduce energy consumption.

 

Real life examples

This Demand Driven Distribution concept is already delivering wide-ranging implications for pumping systems. An example in The Netherlands adopted by Dunea, one of the ten clean water companies who provide drinking water to approximately 1.2 million clients.

The capacity demanded a normal operation consisting of between 80 – 300 m3/h, heads from 22 mwc to 36 mwc. The average capacity requirement for the station is 140 m3/h at 23 mwc; in case of emergencies, the booster station needs to supply 700 m3/h at 36 mwc.

Grundfos proposed a three-pump system consisting of NB 100-315/334 with a rated motor power of 30 kW each. All pumps were to be equipped with VFD and controlled by means of MPC controls. Dunea were impressed by both the design and the fact that Grundfos could supply the complete booster station, including the concrete pit and electrical work.

The complete system has now been operational for some time and the client continues to be impressed with its operation, energy savings and maintenance costs.

Another project that benefited from DDD in terms of reduce leakage and energy costs can be found in Ploesti, in Romania. With 60,000 consumers and a weekly pumped volume of 100,000 m3 per week.  The pressure was 2.9 bar during the day, and 2.6 bar at night.  Non-Revenue Water (NRW) was 30% meaning 1.5 million m3 of water was being lost a year. Following a range of investments, including DDD the upgraded system is saving 50,000 kW/h energy per year and 150,000 m3 in reduced leaks.

SK Water in Denmark is yet another example of DDD at work and their solution has helped them to reduce pipework leakage by 80% in Korsor.

To find out more about these projects, read about others as well as calculate what your savings might be click here.