Energy saving opporutnities
September 1st 2007

Driving air around a plant takes energy and it is often done badly writes Martin Lissenburg, marketing advisor, Economatics Industrial. By addressing this, companies are able to save energy and money and also make a difference in the combat against climate change. In this article a number of energy saving techniques are highlighted

Well, clearly global governmental action is vital to tackle climate change but we shouldn't underestimate the impact of many 'small' actions both at home and at work.

Because air is all around us, there is a risk of seeing it as a free commodity – of course it isn't. Driving air around a plant takes energy and, often, is done very inefficiently. Just think of how often you can hear the air supply! Leaks mean misplaced energy. Compressed Air is commonly used in Industrial facilities (~90% have air use in their processes). It is a utility completely in control of the host business and payback, on energy saving schemes, is usually less than a year; so, it is a very good place to start energy efficiency campaigns. The process starts with an Engineer 'walking the site', as it is vital to take a view of the complete air system. This is supported, if necessary, with air-leak detection and, always, by data logging of the Compressor. The data collection is critical as it gives quantified output that can be acted upon. The data logging process usually lasts around two weeks – long enough for all variations in duty to be monitored.

Economatics work with a customer – a well known manufacturer of roofing products – identified the need for a reduction in operating pressure, the fixing of numerous leaks and the opportunity for diversion of 'waste' heat, from the Compressor, into the workshop during winter, saving alternative heating costs.

The total saving was £25,000 per annum.

The focus often falls, however, on the capital equipment in the process. A Packaging Manufacturer in the North-East found, after the energy appraisal, that their Compressor – a 75kW Rotary Screw – was spending significant amounts of time running off-load. The Compressor was sized to meet certain air demands during the production process, but the demand was variable due to the overall operation of equipment in the factory. This is not an atypical situation in a manufacturing plant.

An Inverter Drive was specified and fitted to the Compressor, such that air was supplied to accurately meet demand requirements, with improved pressure control. The result was a 28% energy reduction over the year and payback for the total project was 12 months. A further benefit was reduction in the excessive wear and tear on the Compressor. The manufacturer is now looking at similar savings on eleven other sites in their Group, plus other areas of energy save.

A further case study relates to the requirement for high quality air – but supplied efficiently. This manufacturer of rock and asphalt products was using a 550cfm Desiccant Dryer, with the associated filtration, to provide its air quality, with standard (timer based) controls for the conditioning and cycling operation. A Dewpoint Switching Controller was specified and installed, such that the Dryer would only condition and cycle as required by the process. This has given a 58% saving in energy usage and payback is eight months, plus the additional benefit of significant reduction in wear and tear.

The above expertise can be applied to any 'process motor'. An Automotive Component Manufacturers paint finishing plant used four pumps operating continuously, but damped to 60% flow by valves in the pipe-work system. Following the energy appraisal, Inverter Drives were installed to each pump motor, allowing the valves to be opened fully and, operating with a transducer, to provide the flow required by the process. The saving in energy was 48% per annum, with payback in nine months. This customer is now reviewing other process applications critically for energy savings. Similar expertise has been applied to process motors used for extraction and air movement, with the same impact on efficiency Economatics launched ECONERGY (Economical Energy) last year, as a business unit dedicated to helping customers identify and implement energy save opportunities and, in turn, save money. Contact them on using the enquiry number below: