Optimizing chiller staging, pumps and cooling towers as one plant

01 · CASE ANALYSIS

Operating challenge

The plant used approximately 41.16 million kWh/year. Large COP differences and operating capacity above calculated demand suggested opportunities in both chiller selection and system staging.

Cooling pumps and tower fans needed to be included in the boundary. Improving a chiller alone does not establish the best total-plant operating condition.

02 · CASE ANALYSIS

Data and performance indicators

The analysis used cooling load, chiller power, COP, UPI, actual/required unit counts, pump power and staging, chilled-water supply/return temperatures, cooling-water temperatures and outdoor dry-/wet-bulb conditions.

Reported average COP was approximately 3.6 and annual UPI approximately 0.90 kWh/RT in the source notation. Average actual staging was 2.7 chillers against 2.0 required; chilled-water ΔT averaged 3.2°C and cooling-water ΔT approximately 4.1°C.

03 · CASE ANALYSIS

Optimization scenario

Prioritize efficient chillers, reduce unnecessary parallel operation and investigate weak units. Coordinate pump staging, differential pressure, flow and load-side valves with the cooling demand.

For cooling towers, consider outdoor wet-bulb temperature, cooling-water conditions and approach together with fan power. The reported annual potential is 6,617,733 kWh, approximately KRW 661.77 million.

04 · CASE ANALYSIS

Measurement and verification

The 16.1% estimate comes from annual operating-data analysis and proposed balance improvements. It is not a confirmed post-implementation result.

Build the baseline with cooling demand, production, weather, operating hours and setpoints. Verify the combined electricity boundary so that chiller and auxiliary savings are not double-counted.

05 · CASE ANALYSIS

Engineering lesson

A plant-level decision must include auxiliaries. Lower chiller input achieved through extra pump or tower energy may not minimize total electricity.