Question 1 : Is My Chiller Plant Operating Efficiently Right Now — Or Just Operating?

Is your chiller plant operating as efficiently as it should be?

For many facility managers in Thailand, this is a surprisingly difficult question to answer. Chiller plants are typically the largest consumers of electricity in commercial buildings, yet they often operate unnoticed in the background until rising energy costs become apparent in the monthly electricity bill.

A modern Building Management System (BMS) does more than simply control a chiller plant. It provides continuous insight into system performance, enabling facility managers to make informed decisions based on real-time operating data rather than assumptions.

This article explores the first—and perhaps the most important—question every facility manager should ask.

Is My Chiller Plant Operating Efficiently Right Now — Or Just Operating?

A running chiller is not necessarily an efficient chiller.

Even when equipment appears to be operating normally, its efficiency can gradually decline due to changes in cooling demand, condenser water temperature, refrigerant condition, fouled heat exchangers, equipment aging, or suboptimal equipment sequencing. These changes often occur slowly and may go unnoticed during routine inspections, while continuously increasing energy consumption.

Because of this, facility managers need reliable performance indicators that measure not only whether the chiller is running, but also how efficiently it is producing cooling.

Two of the most common performance indicators are the Coefficient of Performance (COP) and kW/RT (Kilowatts per Refrigeration Ton).

• COP compares cooling output with electrical energy input. A higher COP indicates better efficiency.
• kW/RT measures the electrical power required to produce one refrigeration ton (RT) of cooling. A lower kW/RT indicates better efficiency because less electricity is needed to deliver the same cooling capacity.

Since kW/RT is widely used by HVAC engineers and facility managers to evaluate chiller performance, it provides a practical indicator of day-to-day operating efficiency.

Formula: kW/RT = Total Electrical Power Input (kW) ÷ Cooling Capacity (RT)

Where:

• Total Electrical Power Input (kW) = Total electrical power consumed by the chiller
  (or chiller plant)
• Cooling Capacity (RT) = Cooling produced, measured in refrigeration tons

How Azbil Helps Facility Managers Answer This Question

At the plant level, Azbil's Advanced Chiller Plant Controller continuously monitors the operating conditions of the chiller plant and automatically optimizes equipment sequencing operating parameters to achieve the highest possible efficiency under changing load conditions.

At the supervisory level, savic-net™ G5 integrates the Advanced Chiller Plant Controller with the building's overall management system, providing centralized monitoring, control, data management, and visualization for the entire facility. In addition to supervising chiller plant operations, Savic-net™ G5 continuously collects operational data, calculates key performance indicators such as COP and kW/RT, compares current performance against historical trends and design benchmarks, and presents the information through intuitive dashboards that enable facility managers to evaluate plant performance immediately.

Rather than relying on routine inspections or waiting for monthly electricity bills to reveal increasing energy consumption, facility managers gain continuous visibility into the operating efficiency of the entire chiller plant. The system also provides proactive alerts when performance begins to decline, allowing maintenance teams to investigate issues before they result in unnecessary energy consumption, equipment failures, or unplanned downtime.

As a result, organizations benefit from:

• Reduced energy consumption
• Improved equipment reliability
• Lower maintenance costs
• Extended equipment life
• Better operational decision-making through centralized, real-time information

With the combination of Azbil's savic-net™ G5 supervisory Building Management System and the Advanced Chiller Plant Controller, facility managers no longer need to guess whether their chiller plant is operating efficiently. They have continuous, real-time visibility into system performance—anytime, from anywhere—enabling smarter decisions that improve energy efficiency, reduce operating costs, and support more sustainable building operations.

---

Question 2 : Are We Running the Right Number of Chillers for Today's Load?

Determining how many chillers should be operating at any given time is one of the most important decisions in chiller plant management—and one of the most common sources of wasted energy.

Many facilities operate more chillers than necessary to maintain a safety margin. While this may seem like a prudent approach, chillers typically achieve their highest efficiency within an optimal operating range. Running multiple chillers at low load can consume more electricity than operating fewer chillers closer to their optimum capacity.

The challenge is that cooling demand is constantly changing. Outdoor weather, building occupancy, equipment usage, and solar heat gain all affect the building's cooling requirements throughout the day. As these conditions change, the most energy-efficient combination of operating chillers also changes. Fixed schedules and manual operator judgement simply cannot respond fast enough to these dynamic conditions.

Azbil's Advanced Chiller Plant Controller continuously analyzes the operating condition of the chiller plant and automatically determines the most energy-efficient combination of chillers, pumps, and associated equipment. By optimizing equipment sequencing and load distribution in real time, it delivers the required cooling capacity while minimizing overall plant energy consumption.

At the supervisory level, savic-net™ G5 provides centralized monitoring and management of the entire building, including the chiller plant. Through a single interface, facility managers can view real-time operating status, energy performance, alarms, and historical trends, providing complete visibility into plant operation and supporting faster, more informed decision-making.

With the combined capabilities of Azbil's Advanced Chiller Plant Controller and savic-net™ G5, facility managers can be confident that their chiller plant is always operating with the right number of chillers for current building conditions—maximizing energy efficiency while maintaining reliable occupant comfort.

---

Question 3 : Is Our Condenser Water Temperature Set Correctly?

Many buildings operate their condenser water system using a fixed temperature setpoint. While this approach is simple, it is rarely the most energy-efficient because cooling demand and outdoor weather conditions are constantly changing.

Lower condenser water temperatures improve chiller efficiency by reducing compressor workload. However, achieving colder water requires the cooling tower fans—and sometimes the condenser water pumps—to consume more energy. Conversely, higher condenser water temperatures reduce cooling tower energy but force the chiller to work harder.

The objective is not to produce the coldest possible condenser water, but to achieve the lowest total energy consumption across the entire condenser water system.

Azbil's Advanced Chiller Plant Controller continuously monitors operating conditions, including condenser water temperature, chiller performance, cooling tower operation, and outdoor weather conditions. Based on real-time plant demand, it automatically determines the optimum condenser water temperature setpoint and adjusts cooling tower operation to maintain the most energy-efficient balance between chiller and cooling tower energy consumption.

At the supervisory level, savic-net™ G5 provides centralized monitoring of the entire building, including the chiller plant. Facility managers can view real-time operating conditions, energy performance, alarms, and historical trends through a single interface, enabling them to verify that the condenser water system is operating at its optimum efficiency.

Facility managers can be confident that the condenser water system is continuously optimized to minimize total plant energy consumption while maintaining reliable cooling performance.

---

Question 4 : Are We Catching Problems Before They Become Expensive?

Most chiller plant failures do not occur without warning. Before equipment breaks down, it often shows subtle signs of declining performance. Energy consumption may increase, cooling efficiency may decrease, or temperatures and pressures may gradually drift away from normal operating conditions.

Because these changes usually develop over time, they can easily go unnoticed during routine inspections. By the time a fault becomes obvious, repairs are often more expensive, downtime is longer, and building operations may be affected.

A Building Management System (BMS) helps prevent this by continuously monitoring the performance of the entire chiller plant. Rather than relying solely on fixed alarm limits, the system records and analyzes historical operating data, allowing facility managers to identify gradual performance degradation before it develops into a major failure.

Typical indicators include:

• Increasing chiller power consumption
• Declining plant efficiency (COP or increasing kW/RT)
• Abnormal chilled-water or condenser-water ΔT
• Increasing evaporator or condenser approach temperatures
• Unstable control valve operation or abnormal pressure trends

At the supervisory level, savic-net™ G5 collects operating data from the Advanced Chiller Plant Controller and intelligent field devices throughout the chiller plant. It provides centralized monitoring, historical trending, alarm management, and performance visualization, enabling facility teams to quickly identify abnormal operating conditions and investigate potential causes before they lead to equipment failure.

By combining reliable field instrumentation with continuous performance monitoring, facility managers gain greater visibility into plant health, enabling proactive maintenance, reducing unplanned downtime, improving equipment reliability, and lowering lifecycle operating costs.

---

Question 5 : Can We Prove That Our Chiller Plant Is Performing as It Should?

Turning Chiller Plant Operation into Measurable Performance

Operating a chiller plant efficiently is no longer enough. Building owners, tenants, and sustainability stakeholders increasingly expect clear, data-driven evidence that energy performance targets are being achieved.

The question is no longer, "Is the chiller plant running?" but rather, "Can we prove it is performing as it should?"

Key performance indicators such as plant energy consumption, kW/RT, equipment operating trends, and verified energy savings provide a clear picture of chiller plant performance. By comparing current performance with historical data and established baselines, facility managers can measure the effectiveness of operational improvements, demonstrate measurable results, and identify opportunities for further optimization.

At the supervisory level, savic-net™ G5 collects and consolidates operational data from the Advanced Chiller Plant Controller and other building systems, providing centralized dashboards, historical trends, alarms, and performance reports. This enables facility teams to make informed decisions based on accurate, real-time information while maintaining complete visibility into chiller plant performance.

For organizations seeking to reduce energy consumption with minimal investment risk, Azbil also provides Energy Performance Contract (EPC) solutions as an Energy Service Company (ESCO). Under an EPC, Azbil designs and implements energy-saving improvements while guaranteeing agreed energy-saving performance. Energy savings are measured and verified using internationally recognized methodologies such as the International Performance Measurement and Verification Protocol (IPMVP).

savic-net™ G5 plays a vital role in this process by providing reliable operational data and comprehensive historical records to establish energy baselines, monitor post-implementation performance, and transparently verify that guaranteed energy-saving targets have been achieved. This enables building owners to confidently validate project results with objective, data-driven evidence.

Even outside EPC projects, the same performance data helps building owners identify hidden inefficiencies, validate the effectiveness of energy-saving initiatives, support investment decisions with measurable results, and continuously improve operational efficiency.

A chiller plant that is not measured cannot be fully optimized. With the combined capabilities of Azbil's savic-net™ G5 Building Management System, Advanced Chiller Plant Controller, and comprehensive ESCO services, building owners gain more than real-time visibility—they gain a trusted partner capable of optimizing performance, verifying energy savings, and delivering measurable results throughout the lifecycle of their energy management journey.