Energy optimization of industrial chiller plants: monitoring and concrete levers
Baptiste
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Energy optimization of industrial chiller units: monitoring and concrete levers
In many industries (food and beverage, chemicals, plastics, pharmaceuticals), chiller units are among the leading sources of electrical consumption on site. They often run continuously, 24/7, and their actual consumption is rarely monitored closely. However, a poorly maintained or poorly regulated chiller unit can consume 20% to 40% more than necessary, without triggering any visible alarm.
This is the paradox of industrial cooling production: unlike a machine breakdown, an energy drift is not visible. The setpoint temperature is maintained, production continues, and no incidents are reported. Only the electricity bill changes, and often too late to identify the cause.
This article presents the key indicators to monitor, the most common drifts, and what IIoT monitoring concretely brings to these refrigeration installations.
Why chiller units remain energy blind spots
On most sites, cooling production is connected to a main switchboard without dedicated sub-metering. Its consumption is therefore drowned in the site total, alongside lighting or compressors. Under these conditions, it is impossible to know if the system is drifting.
This is exactly the logic we describe in our article on the industrial metering plan: you only optimize what you measure. Cooling shares this common point with industrial compressed air and steam, the three most energy-consuming and least instrumented utilities on French sites.
The difference between a site that controls its cooling and a site that suffers from it is rarely due to machine technology. It is due to the presence, or absence, of actionable field data.
The COP: the central indicator for chiller units
The Coefficient of Performance (COP) is the ratio between the cooling energy produced (kWh cooling) and the electrical energy consumed to produce it. A well-maintained chiller unit, in optimal conditions, shows a COP of 3 to 5 depending on the technology and temperature levels. In degraded conditions, this COP can drop to 2 or less, meaning the bill doubles for the identical service delivered.
Calculating the COP continuously requires measuring simultaneously:
the electrical power absorbed by the compressor and its auxiliaries,
the flow rate and temperature of the refrigerant fluid or the secondary circuit,
the outdoor conditions (ambient temperature) to contextualize performance.
This last point is essential: a COP of 3.2 in the middle of August does not mean the same as a COP of 3.2 in February. Without weather contextualization, the comparison has no value and generates false alerts.
With DAT'Power, our energy management IIoT platform, these measurements are centralized and the COP is calculated in real time, plotted on historical curves, and compared to a baseline COP. Any degradation is detected within a few days, long before impacting production or the bill.
The most frequent drifts in industrial chiller units
Condenser fouling
Air-cooled condensers gradually become fouled (dust, fluff, scale on water-cooled models). Fouling increases the condensation temperature, which degrades the COP and puts more strain on the compressor. Regular maintenance can recover 10% to 15% in efficiency. Without real-time supervision, fouling goes unnoticed until failure occurs.
On water-cooled condensers, monitoring the cooling circuit directly intersects with the challenges described in our article on industrial water management and the 2030 regulations: consumption, water quality, and thermal performance are managed together.
Incorrect setpoint settings
Lowering the chilled water supply temperature setpoint by 1 °C unnecessarily increases consumption by 2% to 3%. On an installation of several hundred kW, the effect is immediately significant. Supervision allows identifying the actual applied setpoints and comparing them to effective process requirements, which have often evolved since commissioning.
Undetected degraded operation
A compressor operating with excessive partial load (cycling) or a poorly adjusted liquid by-pass consumes energy unnecessarily. The electrical power curve reveals these behaviors: short and repetitive cycles, abnormal power surges at startup, consumption too high compared to the theoretical operating point.
Lack of intelligent load shedding
On sites where multiple chiller units run in parallel, the lack of intelligent management of startups and load allocation leads to avoidable overconsumption. DAT'Power identifies actual operating sequences and allows optimizing load shedding logic, particularly during simultaneous power surges that impact peak demand.
Fixed high pressure regulation
Many installations retain a fixed condensing pressure, inherited from the original setting. Floating head pressure control, adjusted to actual outdoor conditions, often recovers several COP points in mid-season. However, having the operating history is necessary to demonstrate this and secure the setting.
→ Discover DAT'Power to manage the energy performance of your utilities
Instrumenting an industrial chiller unit: what to measure
An effective instrumentation plan is based on five measurement points:
Absorbed electrical power: energy meter on the dedicated circuit,
Supply and return temperatures of the secondary circuit: PT100 or PT1000 sensors,
Secondary circuit flow rate: electromagnetic or non-intrusive ultrasonic flow meter,
Ambient temperature: essential for air-cooled condensers,
Operating status of compressors and auxiliaries: digital states retrieved via PLC or gateway.
These measurements allow calculating the actual COP, the cooling power produced, and the specific consumption (electrical kWh per cooling kWh).
They also form the basis for eligibility for Energy Savings Certificates via the standardized datasheet IND-UT-134, which finances the implementation of a measurement system for Energy Performance Indicators. This datasheet explicitly covers "cooling" use for equipment with a nominal power of less than 10 MW, which concerns the vast majority of industrial refrigeration installations.
What collection infrastructure?
The question of data transmission systematically arises on existing installations. Three scenarios present themselves:
Equipment is already PLC-controlled: collection is done via industrial protocol, without heavy intervention.
Equipment is legacy or isolated: the deployment of wireless sensors is often the fastest route. Our article on LoRa technology and industrial monitoring deployment details this approach, suitable for remote technical rooms and rooftops where condensers are installed.
The metering plan must be created from scratch: the combination of Carlo Gavazzi meters and DAT'Power constitutes a proven basis for rapidly instrumenting several energy uses.
In all cases, field data collection on a production site requires a controlled architecture. Network segmentation and protection of industrial systems issues are addressed on our dedicated industrial cybersecurity page, as well as in our article on the technical challenges of the connected industry.
Industrial cooling and regulatory requirements
Instrumenting your chiller units does not only meet a cost objective. Several regulatory frameworks converge towards the same measurement requirement:
ISO 50001: cooling almost always constitutes a Significant Energy Use (UES), and must therefore be monitored by documented IPEs.
Regulatory energy audit: mandatory every 4 years for large companies, it gains considerable relevance when the auditor has measured data rather than estimates.
BACS decree and tertiary decree: for chiller units serving commercial spaces, the obligations for automation and consumption reduction apply directly.
In other words, the instrumentation carried out to optimize your costs simultaneously serves your compliance. This is the most profitable double effect of an energy supervision project.
Predictive maintenance: the contribution of DAT'Process
Beyond energy monitoring, the supervision of chiller units with DAT'Process opens the way to predictive maintenance. The analysis of operating signatures (pressure curves, startup profiles, superheat temperatures) allows detecting warning signs of failure:
Compressor bearing wear: abnormal vibration signature or current profile,
Refrigerant charge fault: drop in suction pressure, rise in superheat,
Regulation problem on the electronic expansion valve.
These alerts allow scheduling interventions outside critical production periods and avoiding unplanned shutdowns, which are particularly costly on temperature-controlled processes.
The value of these alerts multiplies when they are connected to the maintenance tool. This is the entire purpose of the integration between CMMS and IIoT supervision: a superheat drift detected by the platform automatically generates a work order, with the technical context already filled in. The technician no longer intervenes blindly.
To further explore this approach, DATIVE and DIMO Maint have co-authored an e-book dedicated to transforming field data into a lever for maintenance performance.
→ Explore DAT'Process for the supervision of your refrigeration installations
How much can be saved?
DATIVE's field experience on instrumented refrigeration installations shows recurring gains:
10% to 15% on electricity consumption after optimizing setpoints and cleaning condensers,
An additional 5% to 10% after optimizing load management on multi-unit parks,
30% to 50% fewer corrective interventions thanks to predictive maintenance.
On an installation with 500 kW of cooling power running 7,000 h/year, a 12% gain represents approximately 40,000 to 60,000 kWh saved per year, or €4,000 to €8,000 depending on electricity prices. Added to this are the CEE premium on instrumentation and the reduction in corrective maintenance costs.
These orders of magnitude are found across other utilities and other industrial contexts:
at Ninkasi, where DAT'Power enabled the management of all fluids at the new production site with savings from the first months,
at an HVAC systems manufacturer, with a multi-UES energy management structured around DAT'Power,
on a high-tier SEVESO site, where the gradual deployment of an energy management system reconciled HSE constraints, cybersecurity, and production continuity.
How to start concretely
A chiller unit supervision project typically unfolds in four steps:
Scoping and metering plan: identify priority units, their power, and their operating regime.
Targeted instrumentation: electricity, temperatures, flow rate, and operating states on the highest-stake machines.
Platform commissioning: construction of IPEs, definition of reference COPs, and alert thresholds.
Continuous improvement loop: analysis of drifts, corrective actions, measurement of actual gains.
The most common mistake is wanting to instrument everything at once. A limited but correctly measured scope produces actionable results within a few weeks and often finances the extension of the project.
The underlying mechanisms, data cross-referencing, automatic anomaly detection, and decision support, are detailed in our articles on the benefits of IIoT for energy management and on the triptych IIoT, data and artificial intelligence.
In summary
A chiller unit that loses 15% efficiency does not stop; it continues to run while consuming far more than necessary. Fouling, unsuited setpoint, drifting COP: these phenomena are silent, costly, and perfectly detectable as soon as the right variables are measured and contextualized.
DATIVE's IIoT platforms transform this field data into actionable indicators, for your energy teams as well as your maintenance teams.
→ Have our experts assess the savings potential on your chiller units
