Cooling-tower fan frequency variation on July 2 under baseline control mode.
A brief single-sample transient around 08:30 was excluded because it did not represent sustained cooling-tower frequency operation.
Plant case
AI operating-period average plant efficiency improved from 0.74 to 0.65 kW/ton, with BMS-compatible control bands, equipment sizes, daily operating data, frequency behavior, and calculation detail shown below.
Calculated for the AI operating period.
Sep 1 to Oct 7 AI control compared with Jun 1 to Jul 7 autonomous control.
Baseline average to AI-period average.
Plant inventory
The site uses a secondary-pump variable-flow chilled-water system. The central plant includes four chillers with one standby unit, four chilled-water pumps, four condenser-water pumps, three air-side chilled-water pumps, and four process-side chilled-water pumps. Normal operation is one chiller paired with one pump.
| Equipment | Brand | Specification | Status |
|---|---|---|---|
| Centrifugal chiller | Trane | Cooling capacity 650RT / Power 402kW | Running |
| Chilled-water pump | Grundfos | Head 20m / Power 30kW / Flow 350m³/h | Running |
| Condenser-water pump | Xylem | Head 22m / Power 45kW / Flow 190m³/h | Running |
| Cooling tower | BAC | Flow 500m³/h / Power 22kW | Running |
Control and BMS compatibility
The platform supports one-click switching between existing group control and AI control. Operators can also apply AI recommendations to group-control setpoints for condenser-water pump frequency and cooling-tower frequency.
Control logic
The control loop reads BMS and weather context, applies explicit operating boundaries, selects a DDQN frequency command, and returns measured feedback to the policy.
BMS + Weather Data
Plant state, trends, operating context
Boundary Checks
Frequency bands, load threshold, protection
ClimaMind DDQN Policy
Frequency command selection
Approved Commands
Condenser-water pump and tower fan frequency
Operator + M&V Feedback
Visibility, fallback, COP and kW/ton review
Cooling-tower fan frequency variation on July 2 under baseline control mode.
A brief single-sample transient around 08:30 was excluded because it did not represent sustained cooling-tower frequency operation.
Cooling-tower fan frequency variation on September 28 under software-optimized mode.
The software-optimized mode modulated tower commands across the day instead of holding the baseline near-fixed tower frequencies; tower running energy fell by about 30% in the comparison window.
Calculation detail
Case result
Efficiency benchmark
U.S. chilled-water plant practice usually compares measured plant performance in kW/ton. The table gives ASHRAE reference context without treating it as a certification claim.
| Metric | Baseline | AI period | U.S. reference context |
|---|---|---|---|
| Plant efficiency | 0.74 | 0.65 | Lower is better; this is the main U.S. operating-efficiency view for chilled-water plants. |
| ASHRAE reference context | 0.61-0.70 kW/ton | 0.61-0.70 kW/ton | ASHRAE District Cooling Guide lists electric centrifugal chillers in this typical range. |
| Measurement boundary | System kW/ton | System kW/ton | Used as reference context, not a U.S. certification score or whole-building energy benchmark. |
Daily operating data
The table below lists daily operating records, and the two plant-efficiency weather scatter plots use kW/ton values from these points.
| Mode | Date | kW/ton | Dry-bulb C | Wet-bulb C |
|---|---|---|---|---|
| Baseline operation | Jun 1 | 0.71 | 21.27 | 18.27 |
| Baseline operation | Jun 2 | 0.73 | 22.46 | 17.78 |
| Baseline operation | Jun 3 | 0.67 | 20.36 | 15.11 |
| Baseline operation | Jun 8 | 0.69 | 21.29 | 17.67 |
| Baseline operation | Jun 9 | 0.70 | 23.23 | 18.43 |
| Baseline operation | Jun 10 | 0.71 | 23.06 | 17.79 |
| Baseline operation | Jun 11 | 0.69 | 21.24 | 17.54 |
| Baseline operation | Jun 14 | 0.69 | 20.80 | 17.49 |
| Baseline operation | Jun 15 | 0.69 | 21.57 | 16.96 |
| Baseline operation | Jun 16 | 0.68 | 20.71 | 16.87 |
| Baseline operation | Jun 17 | 0.69 | 18.25 | 17.24 |
| Baseline operation | Jun 18 | 0.73 | 19.30 | 18.77 |
| Baseline operation | Jun 19 | 0.76 | 20.52 | 19.80 |
| Baseline operation | Jun 20 | 0.77 | 22.31 | 19.73 |
| Baseline operation | Jun 21 | 0.75 | 23.58 | 18.96 |
| Baseline operation | Jun 22 | 0.72 | 22.69 | 17.77 |
| Baseline operation | Jun 23 | 0.70 | 20.24 | 17.18 |
| Baseline operation | Jun 24 | 0.71 | 18.11 | 17.63 |
| Baseline operation | Jun 25 | 0.76 | 21.17 | 19.72 |
| Baseline operation | Jun 26 | 0.76 | 21.62 | 19.60 |
| Baseline operation | Jul 1 | 0.79 | 23.86 | 20.88 |
| Baseline operation | Jul 2 | 0.82 | 24.27 | 21.66 |
| Baseline operation | Jul 3 | 0.82 | 24.67 | 21.84 |
| Baseline operation | Jul 4 | 0.82 | 26.12 | 21.82 |
| Baseline operation | Jul 5 | 0.81 | 25.11 | 21.78 |
| Baseline operation | Jul 6 | 0.85 | 31.39 | 27.41 |
| Baseline operation | Jul 7 | 0.85 | 32.54 | 26.95 |
| AI control | Sep 1 | 0.64 | 26.10 | 21.77 |
| AI control | Sep 2 | 0.63 | 27.06 | 22.70 |
| AI control | Sep 3 | 0.64 | 26.96 | 23.74 |
| AI control | Sep 4 | 0.67 | 28.69 | 25.27 |
| AI control | Sep 5 | 0.70 | 28.18 | 25.15 |
| AI control | Sep 6 | 0.67 | 28.71 | 24.63 |
| AI control | Sep 7 | 0.64 | 28.15 | 24.29 |
| AI control | Sep 8 | 0.63 | 28.17 | 23.43 |
| AI control | Sep 9 | 0.63 | 27.57 | 22.85 |
| AI control | Sep 10 | 0.62 | 27.78 | 22.56 |
| AI control | Sep 11 | 0.64 | 28.80 | 24.47 |
| AI control | Sep 12 | 0.67 | 27.48 | 24.90 |
| AI control | Sep 13 | 0.66 | 25.50 | 23.95 |
| AI control | Sep 14 | 0.63 | 24.65 | 23.29 |
| AI control | Sep 15 | 0.63 | 24.42 | 23.51 |
| AI control | Sep 16 | 0.65 | 25.30 | 23.86 |
| AI control | Sep 17 | 0.65 | 27.73 | 23.87 |
| AI control | Sep 18 | 0.69 | 29.24 | 25.74 |
| AI control | Sep 19 | 0.72 | 30.19 | 26.60 |
| AI control | Sep 20 | 0.69 | 26.86 | 24.41 |
| AI control | Sep 21 | 0.63 | 23.20 | 20.68 |
| AI control | Sep 22 | 0.61 | 21.04 | 19.38 |
| AI control | Sep 23 | 0.62 | 20.42 | 18.89 |
| AI control | Sep 24 | 0.64 | 23.11 | 22.05 |
| AI control | Sep 25 | 0.65 | 26.63 | 23.95 |
| AI control | Sep 26 | 0.66 | 25.63 | 23.42 |
| AI control | Sep 27 | 0.72 | 27.62 | 24.71 |
| AI control | Sep 28 | 0.72 | 25.80 | 24.58 |
| AI control | Sep 29 | 0.73 | 27.40 | 24.55 |
| AI control | Sep 30 | 0.71 | 24.15 | 22.09 |
| AI control | Oct 1 | 0.67 | 23.62 | 19.32 |
| AI control | Oct 2 | 0.59 | 22.95 | 17.60 |
| AI control | Oct 3 | 0.62 | 22.63 | 18.51 |
| AI control | Oct 4 | 0.66 | 23.54 | 18.88 |
| AI control | Oct 5 | 0.61 | 22.26 | 16.79 |
| AI control | Oct 6 | 0.60 | 21.45 | 16.93 |
| AI control | Oct 7 | 0.61 | 19.55 | 16.60 |
We can review BMS points, operating history, equipment sizes, and metering coverage to determine whether a similar AI supervisory layer is practical.
Downloadable resource
Use the PDF version for internal review, project discussions, and sharing the full measured plant case file.
PDF case study, I-P units