A zinc industry company upgraded its compressed air system with two 355 kW screw air compressors. The retrofit focused on improving compressor operation efficiency, matching air supply with production demand, and reducing the electricity consumption associated with compressed air generation.
The customer is a zinc industry company with continuous production operations. Compressed air is used across the production process for pneumatic equipment, process control, equipment cleaning, and other plant utilities.
Because the production system operates for extended periods, the compressed air station represents a significant and continuous electricity load. Improving compressor efficiency therefore became an important part of the plant's energy-saving program.
Before the retrofit, the plant was operating an existing compressed air system that had been in service for an extended period. Its operating efficiency did not consistently match the actual air demand of the production lines.
The main issues considered during the retrofit included:
●High electricity consumption from the existing compressor system
●Limited matching between compressor output and actual plant air demand
●Increased operating and maintenance requirements from aging equipment
●The need to maintain stable compressed air supply for continuous production
Rather than evaluating compressor efficiency as an individual equipment parameter only, the retrofit considered the operating conditions of the compressed air station as a whole.
The upgraded system uses two 355 kW screw air compressors.
The equipment selection was based on the plant's compressed air requirements and the operating conditions of the existing system. The objective was to provide sufficient air capacity while improving the overall operating efficiency of the compressor station.
For a continuous-production facility, compressor selection needs to take several factors into account, including required air delivery, working pressure, operating hours, load profile, and the way multiple compressors operate together.
The retrofit therefore focused not only on replacing equipment, but also on improving the relationship between compressor operation and actual production demand.
The compressor station supplies compressed air to different production processes within the plant. Since air demand changes with production conditions, operating multiple compressors in coordination can help avoid unnecessary operation at inefficient load conditions.
The upgraded configuration was evaluated according to the plant's actual operating requirements rather than relying only on the rated motor power of the compressors.
This approach is particularly relevant for industrial facilities where compressors operate for long periods and electricity consumption forms a substantial part of the compressed air system's operating cost.
Following commissioning of the upgraded compressed air system, the customer evaluated its energy consumption under actual operating conditions.
The retrofit achieved an overall energy-saving rate of approximately 30%.
The result reflects the operating conditions of this specific installation. Actual energy savings from a compressed air retrofit can vary depending on production schedules, annual operating hours, air demand, discharge pressure, compressor loading, and other system conditions.
For this reason, energy-saving performance should be assessed using measured operating data rather than applying a fixed saving percentage to every installation.
Compressed air is often treated as a utility, but compressor operation can have a measurable effect on a plant's electricity consumption.
A suitable retrofit should therefore consider the complete operating profile of the compressed air system. Compressor capacity, pressure requirements, operating hours, air demand fluctuations, and multi-compressor control all affect the final energy performance.
For zinc processing and other continuous-process industries, this system-level approach can be useful when evaluating whether an existing compressor station should be upgraded, replaced, or reconfigured.
This project provides a practical reference for plants with relatively high compressed air demand and long operating hours.
When planning a similar retrofit, plant operators can provide the following information for technical evaluation:
| Parameter | Information Required |
| Existing compressors | Model, motor power and quantity |
| Working pressure | Required operating pressure |
| Air demand | Average and peak air consumption |
| Operating schedule | Daily and annual operating hours |
| Existing energy consumption | Compressor electricity consumption |
| Production conditions | Major changes in air demand |
| Installation conditions | Cooling, ambient temperature and site requirements |
These operating data help engineers determine whether compressor replacement, capacity adjustment, control optimization, or a combination of measures is appropriate for the site.
The zinc industry retrofit demonstrates how compressor selection and system operation can affect the energy performance of an industrial compressed air station.
With two 355 kW screw air compressors and system-level operating adjustments, the project achieved approximately 30% overall energy savings under the customer's actual operating conditions.
For industrial plants considering a similar upgrade, an evaluation based on measured air demand, pressure, operating hours, and electricity consumption provides a more reliable basis for equipment selection and energy-saving assessment.
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