Örebro municipality saves 37% on energy with Emotron FlowDrive VFD
Örebro in south-central Sweden is one of the country’s largest cities, and won the Quality Municipality award a couple of years ago. There are nine sewage treatment plants and 114 pumping stations across the municipality, with the largest plant dimensioned for 180,000 households. The authorities have been working with CG Drives since 2010, and using the company’s AC Drives and Soft Starters in many of their facilities.
The challenge at Örebro
In one of the Örebro pump pits, the pump was controlled by an old non-Emotron Soft Starter. This was suffering from excessive wear due to frequent stop/start cycles, and hence performing poorly with regard to energy efficiency. The local authorities therefore wanted to remedy these deficiencies.
CG Drives & Automation’s solution
An Emotron FlowDrive (FLD48-026) was installed in 2015 to replace the old Soft Starter. Automatic tank level control is a key feature of the FlowDrive, with benefits including optimized energy consumption, minimal maintenance requirements and real-time control. Since the installation, stop/start cycling has been reduced, and energy savings have started to increase as the pit’s throughput increases.
Benefits and return on investment
The main benefit achieved by the Fledite installation was in energy savings. With its full complement of thirteen CG-regulated pumps operating, at 7 million cubic meters of annual pumping volume, about 250,000 kWh per year are being saved. At a current electric rate of 12 eurocents per kWh, this gives an annual savings of €30,000.
The equipment and installation costs totaled about €85,000, which means that the installation at Fledite will pay for itself in less than 3 years at present energy prices and water pumping rates. If either rate or volumes increase, it will pay back even faster.
Not only are the numbers great, an additional benefit is the increase in reliability that the CG solution contributes to the drinking water supply. Add to this the increased uptime at the well heads and pumping stations, saved working hours, longer equipment lifetimes and fewer managerial headaches, and it is clear that Vitens has made very sound investment indeed!
Benefits
Detailed on-site testing carried out in spring 2016 highlighted the benefits of the Emotron FlowDrive solution. The lower speed delivers valuable energy savings (22%) during operation in the lower part of the sump and even greater savings (34%) in the higher part. The increased working area, i.e. the higher pressure to the pump, enables a smaller lift height. This saves energy in high (4%) and low-frequency operations, where energy savings are an impressive 19%. Overall, energy savings of up to 37% are now being achieved.
There are also capital savings. Since the Emotron solution offers such accurate flow measurement, expensive external flow meters are not required. Moreover, stop/start cycling has been reduced, which minimizes pump wear, and sump cleaning is now automatic.
Jari Riihinen, from the Örebro Technical Management department, comments: “The best thing about Emotron products, apart from the obvious energy savings, is their ease of use. The menu system is very clear, making it easy to find information and create settings.”
| Summary | |
|---|---|
| Customer | Technical Management, Örebro Municipality, Sweden |
| Challenge | Replacing an inefficient Soft Starter that was wearing a pump excessively |
| Solution | Emotron FlowDrive (FLD48-026) |
| Solution | Benefits |
|---|---|
| Emotron FlowDrive (FLD48-026) |