Some dramatic benefits are possible, even in relatively short term projects. We were called in to a large plastics manufacturing factory for a single day survey to look at the efficiency of their air systems, driven by a large centrifugal compressor. 

The main issue that they had was that the power readings did not match with the assumed air flow through the system, showing us that there was a significant inefficiency. The compressor was also consistently running at the surge limit. 

We conducted a series of tests using Air Technology’s flow metering equipment and power meters, linking into the compressor control panel. We found that the compressor was running fully turned down all the time, so efficiency was very poor. In essence, the compressor was too large for the operation. That was later confirmed by performance testing the compressor.

Based on this survey and our detailed recommendations, the company commissioned a completely new compressor house, featuring the latest variable speed drive compressors and dryers with heat recovery. The compressors were specified with help from Air Technology to provide efficient operation now and the scope for future expansion later generating excellent savings compared to the old, inefficient system.

We have worked on a number of Water Treatment sites recently, identifying and solving problems that were creating staggering extra costs and energy usage. 

The work we did on three sites alone has resulted in savings of nearly 1.5 MILLION kWhr per year.

At one site, we spotted that compressed air was being being vented to atmosphere because the unloading valve was faulty on two of the site compressors. In addition, on the same site the wrong pulleys were fitted and there was an issue with the control system that stopped the support blower shutting down in low demand periods. The wrong motor mounting plates had been fitted so there was excessive torsional vibration.

These repairs and changes directly led to savings of nearly 400,000kWhr per year

At another site, we discovered that a control DO valve was faulty on one of the site MBBR tanks, reading much lower than the actual DO, resulting in a flow of over 2,500Nm3/hr more than the other tanks. Once repaired:

The resulting saving was over 600,000kWhr/yr

At a third site, we identified and reduced the leakage from the passing drain trap on the aeration pipework. While that directly produced savings of around 10,600kWhr/yr, the investigation identified problems with the control systemm. Once that was changed to turn one of the blowers off at periods of low demand:

Savings were 450,000kWhr/yr

Three surveys, resulting in major energy savings for these sites. None of the changes required capital expenditure, all were repairs or relatively straightforward changes in approach.

A customer reported that they were having to run more compressors that they had previously needed, despite not having increased production. Factory pressure had been lost twice, causing lost production, despite apparently having plenty of compressor power available.

Air Technology investigated the situation and found anomalies in the stage temperatures and, on testing, the screw compressor was found to be producing no air and would only make pressure of 2.6barg. Further investigation revealed the cause of the problem - the first stage dump valve was stuck open and venting to the atmosphere, because of a corroded bolt. Once rectified the compressor operated as expected.

The compressor control panel, and the system controller, showed that the compressor was fully loaded. A simple fix, taking an hour, solved the problem. The site estimated that the issue had been present for five months, costing the company around £12,500.

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