Compressed air products distribution company Goscor KLG recently performed a series of energy audits at various Barloworld facilities, one at Barloworld Power’s main Boksburg campus, as well as at six of Barloworld Equipment’s branches nationally, which indicated that significant energy savings could be achieved by replacing existing oversized compressors with smaller, correctly sized units that use power more efficiently.

The audits typically take seven consecutive days to attain a realistic workload profile of the plant. In addition to Barloworld Power in Boksburg, energy audits were completed at Barloworld Equipment’s Isando, Bellville, Bloemfontein, Durban, Middleburg and Germiston branches.

Goscor KLG project engineer Colin Tyrrell says new Sullair compressors, manufactured by compressed-air solutions company Sullair, have been installed at Barloworld Equipment’s Isando and Bellville facilities and save about 70% and 25% respectively in energy consumption when compared to the original compressor installation.

A Sullair ST1508RD 15 kW compressor was installed at Boksburg , while in Isando, a S_Energy 4507V 45 kW variable-speed drive compressor was installed. However, at Bellville, although the existing 75 kW compressor was replaced with another 75 kW compressor (S-Energy 7507VCC), is this compressor’s variable-capacity control feature – which enables a compressor to mechanically adjust to large variances in the load profile – that made the difference.

Installation of the compressors at the other branches is undergoing capital expenditure processes. “Some of the plants require further investigation regarding medium-term plant expansion and other rationalisation matters that may affect the compressed-air requirements,” notes Tyrrel. Energy audits require an in depth investigation, future expansion and or reduction must be considered to ensure that the proposed installation is correct not only for present plant conditions, but remain efficient for the foreseeable future too.

He explains that the audit process was straightforward. “Our initial audit was based on establishing the exact load profile of the plant and our solution was then tailored to suit this profile.”

Tyrrell adds that older-generation plants are usually fitted with compressors that are oversized for the workload for which they were required. “It is the auditors’ job to accurately define the correct size machine and then determine the correct control system to maximise the savings the new machine can achieve.”

Once a new compressor has been fitted and operational, Goscor KLG performs a post-installation audit to verify that the predicted savings are attained. “If the savings are not being achieved, we are prepared to remove the equipment at no cost to the customer,” he says.

Barloworld Equipment Energy Efficiency Manager TM Lesetla says that constant change in the compressor work environment and the ever-increasing demand for improved productivity makes decreasing energy costs an imperative.

“For this reason, we decided to do a thorough investigation with Goscor KLG to test whether new compressors would be financially viable in the long run. I am pleased to say that the exercise was, indeed, a great success,” he says.

Tyrrell says the entire process with Barloworld has been extremely productive. “Their decision to do the audit was a smart move and working with them has been a positive experience. Energy audits are an important value-adding service that we offer at Goscor KLG and I advise all companies which use compressors to avail themselves of what could be a major cost-cutting exercise,” he concluded.

 

Fact box:

Variable Load Machines

Goscor KLG offers the variable-speed drive (VSD) and variable-capacity control (VCC) solutions to cater for maximum efficiency, these machines allow a base load compressor to operate at full capacity, which is a compressor’s most efficient operating level, as no surplus air  is produced, reducing unnecessary electrical consumption.

Goscor KLG project engineer Colin Tyrrell explains that compressors feature a variety of control systems and, depending on the load profile of the plant, it is ideal to have a base load compressor operating at full capacity. “When the machine is running at full load, a top-up machine (a VSD or a VCC) comes into operation to cater for the variable demand,” he says.

In choosing to use a Variable Speed or Variable Capacity Control machine, the plants varying-load needs to be taken into account. “The VSD can operate between 20% to 80% of full load, but when the demand exceeds 80% it is not cost effective to use a VSD,” says Tyrrel. The VCC machine caters for variable loads ranging between 50% and 100% of the full load and is better suited to plants where the demand is consistently above the 50% mark and regularly exceeds 80%.

Further, VSDs and VCCs can be used for a ‘single’ compressor installations. Although this may be convenient, as it increases the variable range, this type of setup is not particularly common, he says. “It is better to first start with a baseload machine and then install a compressor management system that enhances the savings by selecting the correct compressors to suite the load profile at any time,” says Tyrrel.

 

SAVING ENERGY

The Sullair machines, installed at the Barloworld Equipment Isando and Bellville plants, save about 70% and 25% respectively in energy costs