Saving energy efficiently
EIGHT TIPS FOR ENERGY MANAGERS
Pumps and drives offer huge energy savings potential. By taking the right measures, power consumption can be reduced by up to 90 %. For proof, one need look no further than the projects already implemented by KSB. But how do energy managers approach this complex topic in practice? Where should they start, and which strategy pays off? The following eight tips provide guidance on how you can improve the efficiency of your systems.
Tip No. 1: To reap big rewards, start small
Start with projects that can be tackled with maximum benefit and minimum effort. Studies show that pump drives consume around 300 TWh of electricity annually in the EU, accounting for almost 10 % of the total power consumption. By comparison, lighting plays only a minor role. It therefore makes sense to start with compressors, pumps and fans, as they can be found everywhere. Circulator pumps in heating and air-conditioning systems or pumps in industrial processes and in water/waste water applications offer substantial potential for savings without requiring an excessive amount of work or time. This is confirmed in practice:
Tip No. 2: Pumps offer huge savings potential
KSB’s experts helped reduce the energy consumption of the heating, air-conditioning, water and sanitation systems in Venice’s Palazzo Grassi by 30 %. SAP AG in Walldorf, Germany, focused on its data center. The company was able to save 73 % of energy by optimizing the air-conditioning system of its building services equipment. The ProMinent GmbH in Heidelberg (Germany) reduced its annual electricity costs for the pump test laboratory by around 60 %. This was achieved by modernizing the pumps employed in the company’s water treatment system which uses reverse osmosis, ozone and filtration for water treatment. The general overhaul of the district heating system at the Salzgitter Flachstahl GmbH (Germany) secured a 50 % reduction in power consumption. The key to success: system optimization using new Multitec pumps whose speed is controlled in line with demand. But top of the list comes Heidelberger Druckmaschinen AG (Germany), which achieved phenomenal annual energy savings of 92 %. Experts from KSB analyzed the entire cooling lubricant circuit of the grinding machines and equipped the system with high-efficiency Etanorm pumps in high-end design with PumpMeter, PumpDrive and KSB SuPremE® motors. Pneumatically actuated butterfly valves were installed in the piping and an updated control system ensures optimal use of energy at part-load operation. With these measures, the energy savings add up to well over 10,000 euros per year. It is therefore not surprising that the second system will also be modernized.
Tip No. 3: Focus on medium-sized pumps
Take a walk through your plant or building. Check the pumps used for heating, cooling and water supply systems or other processes. Play less attention to the year of construction and rather concentrate on the control mode and the pump drives’ rated power. Look at the motor name plates. If the motor is equipped with a frequency inverter, it is almost certain that the system uses demand-driven operation. Cataloguing every single pump is nevertheless recommended.
Ignore pumps that have a rated motor power of less than 1 kilowatt. They may often harbor potential savings, but the effort is only justified if hundreds of pumps of this size are in use. Pumps with a rated power of several 100 kilowatts can also be ignored, as you can expect that the system has already been optimized in terms of energy-efficient operation. If you are not sure, consult specialists with the requisite experience.
KSB’s recommendation is clear: Concentrate on pumps with a nominal power of between 3 and approx. 50 kilowatts. Optimizations in this category are easy to implement and comparison offers for optimization measures can be obtained relatively quickly. At the same time, it is easier to obtain approval for the necessary investment as the overall scope remains manageable.
Tip No. 4: Prioritize continuous operation over short-term operation
It is especially important to chalk up successes during the early stages of energy savings projects. Functioning as flagship initiatives, these can create momentum for further projects and act as a conduit for experience gained. It therefore makes sense to pay particular attention to pumps that are operated continuously, as the savings grow with increasing operating hours. Plant inspection tours should therefore be repeated at night, at weekends or outside production times. If you come across a pump operating at these times with a hot motor – especially if it is making a lot of noise – then you have identified a promising candidate for the next project. If the motor power cable has become yellow or brittle due to heat, this is also an indication for inefficient operation. A lack of frequency inverter on the pump or in the control cabinet serves to corroborate this evidence.
Tip No. 5: Use tools available
By monitoring the motor noise of a fixed-speed asynchronous motor, the free KSB Sonolyzer® app can determine whether the operating point lies in the part-load range and whether potential savings are possible. Further measurement need then only be performed in cases where the prospects for economic benefits look promising. The app is available for download from the KSB web site free of charge.
Once potential energy guzzlers have been identified, intelligent pressure sensors such as KSB’s PumpMeter determine the operating point, thus providing reliable figures for the actual optimization potential. PumpMeter measures the difference in pressure between the inlet and outlet of a centrifugal pump. The operating point is displayed as a characteristic curve on the measuring instrument and can immediately be evaluated. The load profile, obtained as a histogram, can be stored for up to ten years and accessed at any time via a software program. Based on this data, the economic efficiency of optimization measures can be determined quickly and easily. And this is the basis for any investment decision. Following the implementation of energy saving measures, PumpMeter serves to continuously monitor and optimize pump operation.
Tip No. 6: From small to big
After examining the pumps, enlarge your radius and set your sights on the system as a whole. It is often here that you can find the best opportunities for efficient savings. Asking questions regarding the system helps identify and tap this potential: Do the pump and its operating mode match the system’s demand? Does the pump run continuously or occasionally? Was a thermostat installed in the past and then taken out of service? Is the pump controlled by the boiler’s control system? Has the pump been switched from automatic to manual mode at some point in time? When was it last serviced? This information usually results in a reliable action plan.
Tip No. 7: Consult experts
If you have not already done so, now is the time to consult the experts. At this point concrete measures must be calculated and implemented on the basis of the data obtained. It might be necessary to select new pumps, pump control systems or impeller geometries, or consider aspects regarding the efficiency of the entire system. Both require the expertise and extensive experience of pump specialists.
Tip No. 8: Don’t get overwhelmed – focus on one project
It is important to start out on one project and pursue optimization potential until the end. Not until this has been completed should you address new challenges. A successful project can be reiterated later and stands to benefit from the experience and momentum gained during the previous undertaking.
In the end, pursing this cycle represents good energy management and ultimately a successful energy manager.