|Original arrangement:||Electro-mechanical drive:|
|Shaft power at low operating point with fixed speed arrangement||Shaft power at low operating point with controlled speed|
|1,700m @ 500m3/h at 71.0% efficiency (5,580 ft @ 2,200 USGPM at 71.0%)||1,143m @ 500m3/h at 75.8% efficiency (3,750 ft @ 2,200 USGPM at 75.8%)|
|Power: 2,944 kW (3,950 hp)||Power: 1,854 kW (2,485 hp)|
The new arrangement provided a power saving of 1,090 kW which translates into a considerable saving every year that has been estimated between €218,000 ($237,000) and €436,000 ($475,000) depending on the annual operating hours. Furthermore, the initial installation costs are lower than those for a variable speed drive and the overall efficiency is higher.
As with all control technologies there are both advantages and constraints that must be considered when implementing this type of system. The overall footprint of the solution can be a major factor, especially on retrofit situations. In this case, the electro-mechanical drivetrain enables the main drive motor to be connected directly to the grid, removing the need for bulky speed control equipment.
However, this solution does have limitations and can currently only be used with equipment drawing up to 20 MW (26,800 hp) of power and with a maximum speed of 14,500 rpm. Nevertheless, these constraints still allow for a considerable amount of equipment to benefit from the latest innovation in speed control for large scale pumps.
Pumping applications around the world account for a significant percentage of global energy consumption. Creating savings such as those in the example above will have a major benefit for applications that use medium and high voltage drives to power high performance pumps, such as those used in the oil and gas, petrochemical and mining industries.
As pressure increases on most industries to reduce manufacturing costs and minimize overheads, so it becomes all the more important to question the conventional thinking on motor control. There is, of course, no single answer for every application but as new solutions become available they should be examined for suitability.
In situations where pumping applications experience a change in duty requirements, many will benefit from an improvement in design. This can be delivered by retrofit experts that offer advice, design proposals and complete installation services based on years of experience.