Why servicing Turbocor compressors is a job for experts
The technology gap between Turbocor compressors and conventional compressors is like the gap between an F1 car and a normal road car. Enter then the specialist service engineer, as Roberto Mallozzi and Ken Strong explain.
The principles behind the Turbocor compressor for chillers are completely different to conventional compression systems, as explained below. The high-performance technology has proved to be exceptionally reliable. However, when units do need servicing it is vital to use trained specialists or very serious problems can occur.
There is a growing estate of these high-efficiency units in the field. The Turbocor-based chiller, in the form of the award-winning Turbomiser and several market variants, has proved to be one of the industry’s success stories of the past few years.
Sales of these high-efficiency machines have risen every year since their launch five years ago. According to the latest industry figures, Turbocor-based machines is the only sector of the chiller market currently growing. While sales of chillers with reciprocating, screw and scroll compressors fell last year, those of Turbocor machines rose by 50% and are forecast to increase again this year.
As the installed base grows, the issue of ensuring effective and timely servicing comes to the fore.
It is known that the oil-less design and reduced number of moving parts have major benefits in terms of reduced servicing. Along with its low energy consumption, this is one of the main attractions of the technology versus conventional chillers, which rely on maintenance-hungry oil-based lubrication systems.
Although the servicing needs of Turbocor machines are significantly reduced, for the periodic servicing that is required it is crucial to ensure this is carried out to the highest standards by knowledgeable and well trained engineers.
Turbocor can deliver outstanding performance but needs expert back-up at the right intervals to ensure it stays in optimum condition — and continues to perform.
The compressor is based on a two-stage centrifugal impeller and spindle, which is levitated in a powered magnetic bearing. A DC inverter powers the motor, and the system is controlled by a highly sophisticated onboard microprocessor.
In the same way that it would be unwise to employ a back-street garage mechanic in the pits for an F1 championship, it is risky and potentially dangerous to let an untrained service engineer loose on a Turbocor.
There have been instances where field engineers or enthusiastic end users untrained in the technology have tried to tackle Turbocor servicing themselves. In some cases, this has resulted in severe damage to compressors and put the chiller out of action.
The truth is that the principles behind the technology are completely different to conventional compressors. On a mechanical level, with its single moving part —shaft and related impellers — Turbocor is deceptively simple. However, related support systems, particularly the electronics, are highly sophisticated. Handling it safely and effectively requires specialist training.
A key requirement is to ensure that electronic components contained within Turbocor are protected from moisture. Because these components are critical to Turbocor’s performance, this aspect is part of a regular annual service that needs to be carried out according to a set procedure.
Turbocor also has a bank of high-power capacitors on the side of the compressor case to bring the unit to a controlled stop if the mains fails. Owing to normal deterioration over time, it is necessary to replace the capacitors after 10 years. There are serious health-and-safety issues in handling these components because of to the enormous voltages that could cause serious injury in untrained hands. For this reason, the procedure must be done by a properly trained Turbocor technician.
One of the advanced features of Turbocor is its on-board data collection, management and diagnostic system. Trained service technicians can connect up a lap-top and access a full history of a machine’s current and past performance. This shows COPs, capacity, output and any faults or alarms since the last service.
Evaluating this data effectively requires training in the Turbocor operating and diagnostic system. The interface can also be used to make adjustments to key system parameters; without proper knowledge, it would be possible to create potentially unsafe conditions that could seriously impact the performance of the chiller.
In the case of our Turbomiser chiller, the compressor controls are integrated with the overall chiller controls to optimise performance for a given set of conditions. This can deliver exceptional efficiencies. To get the best from the system, however, it can be beneficial to make fine adjustments to seasonally tune the machine to ambient conditions and maximise efficiency.
Again, this requires knowledge of both the Turbocor operating system and the over-arching chiller controls to ensure the correct integration and tuning to design conditions.
Effective leak detection is an increasingly important area, and with Turbocor requires a careful approach. The compressor is renowned for its leak tightness, but because it does not use any oil, engineers cannot rely on the conventional approach of spotting oil leaks as a clue to possible points of refrigerant leakage. The correct use of electronic or ultrasonic refrigerant leak detection is therefore needed when servicing the machine.
The number of installed Turbomiser and Turbocor-based chillers is set to grow. As energy prices rise, sales of these high-performance machines will continue to displace traditional screw and reciprocating chillers.
The technology is transforming the energy efficiency of data centres, hospitals, offices, banks and shopping centres and dramatically reducing the cost of servicing chillers in the field.
For the reasons highlighted, however, it is vital that the servicing required by these thoroughbred machines is carried out by specially trained service engineers. The safety of the servicing engineer and the security of the process or building being cooled depend on it.
Roberto Mallozzi is with Klima-Therm and Ken Strong is with Cool-Therm.