CASE18 · Manufacturing · Compressed air
Compressed-air UPI and control optimization in a chemical plant
Low- and high-pressure compressor systems were benchmarked using specific electricity consumption, unit staging, pressure and BOV/IGV behavior. Additional savings opportunities were identified even though baseline performance was already better than the peer average.
01 · CASE ANALYSIS
Operating challenge
The objective was to quantify additional improvement in an already efficient compressed-air system. The low-pressure UPI was 0.102 kWh/m³ and the high-pressure UPI 0.107 kWh/m³, both below the reported peer average of 0.114 kWh/m³.
The diagnosis went beyond individual compressor efficiency to examine how each machine responded to changes in airflow, load and control demand.
02 · CASE ANALYSIS
Data & method
Annual electricity, supply airflow, active units, load factor, supply pressure and UPI were combined with individual power, blow-off valve (BOV) and inlet guide vane (IGV) positions.
Representative two-day windows in January, April, July and October were examined to relate airflow changes to power and BOV response. Peer benchmarks informed realistic target UPI values rather than treating peer averages as universal targets.
| Indicator | Low pressure | High pressure |
|---|---|---|
| Electricity | 11,883,933 kWh/year | 21,882,017 kWh/year |
| Average power | 1,357 kW | 2,498 kW |
| Average airflow | 13,939 m³/h | 24,657 m³/h |
| Average active units | 2.0 | 3.5 |
| Average system load factor | 94% | 98% |
| Average supply pressure | 4.29 kg/cm² | 7.73 kg/cm² |
| UPI | 0.102 kWh/m³ | 0.107 kWh/m³ |
03 · CASE ANALYSIS
Proposed measures
Stage compressors to meet changing demand, improve load sharing and reduce inefficient part-load operation. Minimize unnecessary blow-off and tune inlet control across machines.
Stabilize system and individual-compressor pressure within process requirements. Proposed UPI targets were 0.097 kWh/m³ for the low-pressure system and 0.101 kWh/m³ for the high-pressure system.
04 · CASE ANALYSIS
Savings potential
The report proposed 592,224 kWh/year for low pressure and 1,125,530 kWh/year for high pressure, totaling 1,717,754 kWh/year. Reported combined cost potential was KRW 171.775 million/year.
These values are pre-implementation estimates from target UPI assumptions, not confirmed post-project savings.
| System | Target UPI | Electricity potential | Cost potential |
|---|---|---|---|
| Low pressure | 0.097 kWh/m³ | 592,224 kWh/year | KRW 59.222 million/year |
| High pressure | 0.101 kWh/m³ | 1,125,530 kWh/year | KRW 112.553 million/year |
| Total | — | 1,717,754 kWh/year | KRW 171.775 million/year |
05 · CASE ANALYSIS
Measurement & verification
Compare UPI and electricity at comparable compressed-air demand, pressure, production and operating hours. Align the measurement intervals for airflow, electricity, staging and loading/unloading.
The system boundary matters: reducing power alone does not demonstrate efficiency improvement if useful airflow or required pressure also declines. Future analytics could support load forecasting or abnormal-operation detection, but this case does not claim AI implementation.
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