To buy or not to buy: Datalogging helps with decision
July 01st 2010

Using compressed air efficiently is an important part of any successful energy management programme. Here, Andy Jones, general manager at Mattei, looks at ways companies can make the most of compressed air.

Reducing energy consumption is high on everyone’s agenda at the moment, not only as a result of the Government’s drive towards a green society, but for individual companies that need to bring down costs. While compressed air is a safe and versatile application, if an inefficient system is used, it can prove expensive. Investing in a new compressor isn’t always feasible and, in some cases, it simply may not be necessary.

To ensure the right decision is made, companies can use a data logging exercise to identify where changes can be made. Many leading manufacturers, including Mattei, offer this service, which will not only provide information on the steps that can be taken, but also the expected result of implementing these changes.

Datalogging will also identify where savings can be made by using a different compressor configuration, or in some cases, by investing in new equipment.

In addition, datalogging can highlight whether there is a variable need for compressed air. A business’s use can change over time, and therefore changing existing equipment – either from or to – a variable speed compressor, has the potential to make a significant difference to energy consumption and overheads.

At PetroChem Carless a data-logging exercise by Mattei revealed the potential savings of changing existing equipment. The investment in new, highly energyefficient compressors will save in excess of 430,000kWh per annum at the Harwich refinery, meaning the equipment will pay for itself in just two years.

The refinery operates continuously 24/7 and the reliability of its compressed air supply is a key consideration, as any failure would cause costly downtime. The supply serves a variety of requirements including instrument air, valve actuators and air driven motors. Prior to the datalogging, Petrochem Carless used two 90kW Mattei compressors installed 12 years previously and was backed up by service support from the manufacturer.

The decision to invest in new technology was made both on the basis of saving energy and also taking into consideration the need to secure the supply of compressed air to the plant in the future.

To first determine the integrity of the air supply, the refinery commissioned an air leakage survey to be carried out prior to the datalogging exercise. This identified minimal leakages, confirming the effectiveness of the site’s maintenance procedures and enabled the focus to be placed on the energy-saving potential of the compressors themselves. The exercise also proved there is a consistent demand for air due to the continuous operation of the plant. Based on this information, Mattei recommended two Maxima 75kW fixed speed compressors which, it was estimated, would save in excess of 430,000kWh per annum. Although effectively down-sizing from 90kW to 75kW machines, the replacements were shown to be capable of delivering the same total volume of 32m3/min of air.

This enhanced output capability is a benefit of the Maxima technology, which is able to use a 6-pole motor that then runs the air end at the optimum low speed of 1000 rpm, giving maximum output of air from the minimum consumption of energy. With blades designed for more than 100,000h of life and reduced maintenance requirements, the Maxima machines also offer maintenance cost savings.

Installed in 2009, the compressors were data logged as a monitoring exercise after a few months of service. The exercise confirmed the estimated annual saving of more than 430,000kW/h. The success of the datalogging service shows it is a reliable way to find the best approach, and – if new equipment is the right option – then it will highlight suitable technology.

Leak detection is another vital service in ensuring businesses are offered the right advice – after all, there is little advantage in introducing a more energy efficient compressor if the energy is still going to be wasted through leaks in the system.

More articles from Mattei Compressors Ltd: