Cooling plant case

Hospital cooling plant

A mixed centrifugal and screw-chiller plant used API integration to optimize chiller leaving-water temperature, pump frequencies, and cooling-tower frequency.

Energy reduction
32.18%

Calculated from comparable daily average energy.

Baseline daily energy
3,470.24 kWh

Baseline period average, Oct 5-Oct 10.

AI daily energy
2,353.38 kWh

AI full-day period average, Oct 12-Oct 19.

Plant profile

Four chillers with large and small pump trains

The plant used two centrifugal chillers and two screw chillers. Large pumps and towers served the centrifugal chillers; smaller pumps and towers served the screw chillers. Pumps and towers were variable-speed capable.

Equipment

Operating equipment

The equipment inventory included parallel large and small trains across chillers, chilled-water pumps, condenser-water pumps, and cooling towers.

EquipmentQuantitySpecificationStatus
Centrifugal chillers22461.9 kW cooling capacity / Nominal efficiency 0.56 kW/tonRunning
Screw chillers2843 kW cooling capacity / Nominal efficiency 0.60 kW/tonRunning
Large chilled-water pumps375 kW / 36 m head / 466 m³/h flowRunning
Small chilled-water pumps330 kW / 34 m head / 160 m³/h flowRunning
Large condenser-water pumps345 kW / 22 m head / 556 m³/h flowRunning
Small condenser-water pumps318.5 kW / 22 m head / 190 m³/h flowRunning
Large cooling-tower groups27.5 kW x 3 / 615 m³/h flowRunning
Small cooling-tower groups27.5 kW / 205 m³/h flowRunning

Control scope

Integration
AI optimization connected to the air-conditioning platform through API.
Variables optimized
Chiller leaving-water temperature, chilled-water pump frequency, condenser-water pump frequency, and cooling-tower frequency.
Weather comparability
Baseline average outdoor temperature 21.72 C; AI period average 22.07 C.

Calculation detail

Baseline window
Oct 5-Oct 10; average total energy 3,470.24 kWh/day; average outdoor temperature 21.72 C.
AI window
Oct 12-Oct 19; average total energy 2,353.38 kWh/day; average outdoor temperature 22.07 C.
Transition day
Oct 11 was excluded because AI was connected during the morning.

Formula

Energy reduction = (Baseline daily average energy - AI daily average energy) / Baseline daily average energy x 100%

Case result

(3,470.24 - 2,353.38) / 3,470.24 x 100% = 32.18%

Daily operating data

Daily operating data

The scatter plot uses the measured daily total energy and outdoor average temperature. The transition day is shown in the table but excluded from the comparison and fitted lines.

2000300040005000600021222324Outdoor average temperature CkWh/day
Baseline controlAI controlTransition day
ModeDateChiller kWhChilled-water pump kWhCondenser-water pump kWhCooling tower kWhTotal energy kWhOutdoor average temp C
Baseline controlOct 54422.43667.23409.36393.00589223.68
Baseline controlOct 63866.14485.04277.08209.00483721.20
Baseline controlOct 73354.48486.27286.75224.24435220.99
Baseline controlOct 83861.93491.30312.49219.62488521.28
Baseline controlOct 92742.01447.16238.87214.30364221.56
Baseline controlOct 102574.44393.44224.76218.23341121.59
Transition dayOct 111653.96327.09132.25204.40231821.42
AI controlOct 123080.84504.61186.13213.33398521.78
AI controlOct 132408.67402.85135.16214.97316223.21
AI controlOct 142959.52415.65169.42207.22375222.33
AI controlOct 152082.68382.04139.65198.54280322.35
AI controlOct 162730.15460.97181.67210.36358322.06
AI controlOct 171351.56335.12116.99196.66200021.54
AI controlOct 182151.34340.96155.24220.79286821.59
AI controlOct 192062.27328.67129.29210.81273121.66

Compare your plant against these operating patterns.

Bring plant topology, BMS trend logs, and utility data. We will map what can be measured before proposing an optimization scope.

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