Danfoss Drives in the Water industry
Danfoss in the water industry
Our tight focus on energy efficiency at every stage of development, including the net efficiency when the new generation VLT® AQUA Drive is installed, means that you get a drive that delivers cost savings of up to 25% of the investment in the drive in its first year, when compared to traditional AC-drive solutions. That’s the equivalent to the savings gained by choosing an IE 3 motor instead of an IE 2.
Drinking water production
Whether surface water or groundwater is used for water production, the VLT® AQUA drive 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.
Drinking water distribution
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 AC drives 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.
Wastewater canalization system
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 an AC drive 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.
Wastewater treatment plants
The latest buzzwords in wastewater treatment plants are ‘Bio refinery’ and ‘Water Resource Recovery Facilities’. These cover the general acceptance that wastewater has to be considered as a resource from which both energy and valuable resources can be gained. In some of the most advanced cases, energy production has now (even without adding external carbon resources) got to a level where the energy recovered from wastewater treatment process not only covers the plant’s own needs, but also the energy needs for drinking water production and distribution as well as wastewater pumping. In other words, the whole water cycle can be considered energy neutral.
A precondition for energy neutrality is a control handle in the form of an AC drive available for all rotating equipment, so that the fully computer-controlled facility can adapt to the changing load. Typically, 30–60% of energy is used in the biological process; AC-drive control can usually cut energy consumption by 20–40%. Sludge age control by control of the RAS pumps is similarly important to both limit energy consumption and also avoid ‘burning’ carbon, which is needed in the digester for generating gas for energy production. The VLT AQUA Drive has been chosen for some of these most advanced facilities, where high installed efficiency of the drive and greater reliability and ease of operation have been key selection criteria.
Industrial water and wastewater
The importance of a clean and stable water supply as well as taking advantage of opportunities to make major cost reductions on the wastewater-handling side has been realized by many industries. Some industries are even moving towards a zero, or very close to zero, water use. On the clean water side, this requires utilization of advanced water treatment technologies such as RO and ultrafiltration. The VLT AQUA Drive helps improve process reliability and reduce operation costs. On the wastewater handling side, the trend is similar to the municipalities’ vision; wastewater should be seen as a resource from which energy and other resources can be obtained.