Are variable speed compressors a sensible option?
Third Quarter 2004
Pneumatic systems & components
Perimeter Security, Alarms & Intruder Detection
Generally it is believed that variable speed technology offers the most efficient method of producing compressed air.
In the First World where it was conceived, it may be a plausible solution when one considers the cost of their electricity and high operating standards. However, in South Africa, we probably have the cheapest electricity in the world, which casts an overwhelming doubt on the actual benefit of variable speed - energy saving, in relation to the capital cost of this type of technology.
The fact that a variable speed drive compressor can only be totally effective in a plant that has extreme fluctuations, (variable), in air demand, implies that the plant has to either be running at maximum efficiency, in other words with zero air wastage, or alternatively, the compressor has to be substantially over-sized in order to obtain the energy-saving benefit of operating at various speeds.
Rather a catch-22, I would say!
Invariably however, such plants do not exist in the real world. It is thus very dangerous to believe that variable speed technology will offer the best economical solution to your air requirement. Inherently, this type of technology is maintenance-intensive and can become costly in terms of sophistication if the plant is neglected. Particularly in SA, we have to accept that the level of skills on the workshop floor is way below First World standards, due to the fact that product knowledge is kept privy by the local suppliers and training is only available at a premium.
Besides these primary contentions, one also has to consider that the physical design and character of the rotary screw air end prohibits optimum efficiency at varying speeds and therefore the quoted percentages of energy savings, due to variable speed operation, become intangible values rather than real savings. A further consideration is the life expectancy of the unit. Generally, the VSD compressors design parameter, prescribes an optimum efficiency at mid-speed, (3000 rpm), where the unit is intended to run most frequently, which means that the chosen air end on the relative model compressor, would have the best performance at this speed. If the unit has to run at the top speed, (6000 rpm), it will not be running efficiently or comfortably and it becomes very expensive to maintain and operate.
It is thus most important to understand that if a VSD compressor is installed in an unbalanced compressed air reticulation that is not constantly maintained, the unit will eventually become a full base load compressor due to the fact that it had to be oversized during the original selection process and without consistent monitoring, which is normally the case with compressor plant, the unit will eventually run unnoticed at top speed, thereby defeating the original objective.
For more information contact Kevin Rushmer, Air Bank, +27 (0) 11 908 4169.
Further reading:
It’s full steam ahead for SKF’s sustainable leak detection solution
SKF South Africa
Pneumatic systems & components
One of SKF’s key customers based in Cape Town, which depends on steam systems for its production processes, was facing costly challenges related to high energy consumption and excessive maintenance hours. SKF recommended the TKSU 10 ultrasonic leak detector as a more streamlined, user-friendly alternative.
Read more...
A guide for compressed air dryer selection
Artic Driers International
Pneumatic systems & components
Clean and dry compressed air is essential in today’s modern operating environment. Without an air dryer and filter bank in line, the downtime created by condensate can be substantial. However, there are issues about air dryer selection and the impact of geographic location that need careful consideration prior to placing an order.
Read more...
Easy to use energy management tool for compressed air
Comtest
Pneumatic systems & components
For the efficient management of plant operations, the critical considerations include product quality, safety, downtime, and energy use. A production plant in Germany has set a greenhouse gas emissions reduction goal of 25% by 2030, and turned to the Plant Energy manager to help deliver that target.
Read more...
How intrusion protection helps secure O&G operations
Surveillance Perimeter Security, Alarms & Intruder Detection Industrial (Industry)
For O&G operators in Africa, physical security remains one of the biggest considerations, particularly when it comes to perimeter protection and the ability to mitigate intruder-related incidents.
Read more...
Gallagher’s Integrate 360 event in Durban
Gallagher
News & Events Perimeter Security, Alarms & Intruder Detection
Gallagher Security held its Integrate 360 event in Durban, South Africa. The event attracted 65 channel partners, end users, and consultants from across KwaZulu-Natal and broader South Africa to showcase the latest in Gallagher’s technology suite.
Read more...
Nice launches DC Blue Astute garage door motor
Nice Group South Africa Technews Publishing
News & Events Access Control & Identity Management Perimeter Security, Alarms & Intruder Detection
Nice Systems SA has launched the Nice DC Blue Astute, a garage door motor for the South African market featuring a pre-installed lithium-ion battery instead of traditional lead-acid batteries.
Read more...
Compressed air solutions for efficient pneumatic conveying
Pneumatic systems & components
Moving goods through pipes from one point to another using air - pneumatic conveying - is an extremely efficient method of transporting a great variety of products, provided that the right system is used, and that it’s done correctly.
Read more...
Compressed air preparation
Artic Driers International
Pneumatic systems & components
The choice of compressed air dryers is driven by the air quality demands of your plant.
Read more...
Compressed air treatment do’s and don’ts
Artic Driers International
Editor's Choice Pneumatic systems & components
As a long-established importer and manufacturer of air dryers, Artic Dryers often sees the results of poor installation and issues with aftercoolers that create serious problems in air drying systems.
Read more...
Next-gen air compressors for plastics manufacturer
Pneumatic systems & components
Integrated Air Solutions has reinforced its partnership with global compressor manufacturer, ABC Compressors by facilitating the installation and commissioning of two next-generation direct-drive ABC machines for a prominent plastic manufacturer in South Africa.
Read more...
printer friendly version