Drives for water pumping

Whether surface water or groundwater is used for water production, Danfoss VFDs can help optimize the process and reduce energy and maintenance costs. A typical application is the control of deep well pumps, where the integrated advanced minimum speed monitor secures sufficient lubrication to protect the pump. Energy savings are achieved by selecting wells based on water level height. The VLT® AQUA Drive is also widely used in the desalination industry for controlling inlet and high-pressure pumps as well as booster pumps in relation to energy recovery.

Within the water supply, drinking water distribution is typically the largest energy consumer. At the same time, 25–50% leakage is not unusual. By dividing the water distribution into pressure zones, the average pressure can often be reduced by 30–40%. The VLT® AQUA Drive is very widely used in boosting pumping stations to regulate pressure in each pressure zone. Integrated application software functions, such as Sleep mode, Dry run detection, Automatic Energy Optimization (AEO), Cascade control, Automatic flow compensation and Ramp functions help simplify the installation and make it more reliable, reduce the risk of water hammer, control pressure and reduce energy consumption. 

With access to water resources becoming scarce in some regions of the world, efficient and sustainable irrigation is becoming more and more important. It’s all about supplying enough water to get maximum crop yield without using more water and energy than absolutely necessary. Danfoss VFDs adapt pressure or flow rate to the actual need. And integrated application software functions help to both protect the pipe system by limiting pressure boost and cut energy consumption.

The ultimate solution, and a very fast-growing trend, to reduce energy consumption is to use solar-powered pumps. Danfoss Drives has developed a dedicated inverter series exactly for this purpose. The VACON® product range includes a specially designed encapsulation for this environment and advanced software, meaning that operation is possible even when clouds are partially blocking sunlight from reaching the photovoltaic panels.

Energy optimization and SCADA control of the wastewater canalization system is also a fast-moving trend. By using the VLT® AQUA Drive’s integrated deragging function, it is possible to improve pump efficiency by 15–30% and also drastically reduce maintenance costs. The deragging function prevents pump efficiency from dropping by increasing clocking and extends pump maintenance intervals. Using VFDs together with a SCADA system also offers the possibility to secure maximum utilization of the volume capacity in the canalization system in relation to storm water overflow.

The energy used in the water distribution system typically represents 60–80% of the total energy consumption for the whole water supply system. By adapting the pressure to the real need using pressure zones and boosting pumping stations, you can achieve energy savings of 25–40%. At the same time, you can reduce water leakage by 30–40%.

Regulating the pressure in the network can also provide the following benefits:

• a 40–55 % reduction in the amount of new pipe breaks 
• a reduction in maintenance costs and expensive pipe and road repair
• limited risk of bacteria and contamination of tap water (infiltration)
• extended service life of the network 
• postponed investment in plant upgrades
• reduced risk of water hammer