Case study
Chiller plant integration and energy monitoring across a mixed-vendor facility
Four chillers from three vendors, plus cooling towers and AHUs, brought onto one head-end with metering placed to answer two specific questions.
The problem
What we found
Four chillers from three manufacturers, each with its own controller, its own front end and its own alarm convention. Cooling towers and AHUs on a fourth system.
With no plant-level sequencing the machines competed: two would load against each other at part load, and nobody could say what the utility actually cost per hour.
The constraint
A qualified facility. Nothing could be done that would invalidate the chillers' own manufacturer warranties or disturb the qualified environmental control.
The approach
How it was done
- 01
Integrate, do not replace
Every machine kept its own controller. Integration was over BACnet/IP and Modbus TCP to what each unit already exposed, which in two cases was considerably less than the datasheet implied.
- 02
Sequencing at plant level
Duty selection, staging and run-hour balancing implemented above the machine controllers rather than inside them, keeping warranties intact.
- 03
Metering to answer two questions
Rather than a full submetering scheme, meters were placed to answer the two questions the site actually had: cost per production area, and whether chiller three was drifting. Nine meters, not forty.
- 04
One alarm philosophy
All four systems presented on the site's existing WinCC head-end with a single alarm priority scheme, so facilities staff read one convention rather than four.
The result
What changed
Part-load competition between machines eliminated by plant-level sequencing.
A monthly energy report by production area that the site's energy programme uses, produced automatically rather than compiled by hand.
Next step
Something similar on your site?
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