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Chiller: Questions to ask

Manager - Energy Management

Eng. Sujeewa Fernando

Manager - Energy Management

Access Energy Solutions


Air conditioning has become an expected standard of comfort (P1-4)

Many people have come to expect cool, comfortable temperatures in commercial and work spaces. Which makes the air conditioning systems that enable this an essential part of our lives and an expensive part of many companies’ overheads.


Layout of a typical chiller system. A detailed explanation of this diagram can be found in our article understanding chiller systems. (P5)

What are these Systems?

Due to their ability to cool far below surrounding temperatures, chilled water systems are a common type of central air conditioning system in Sri Lanka.(1) Recent technological advancements in these systems have significantly improved their efficiency, and can help a building to save on its energy overhead. However, upgrading a chilled water system is much more challenging than replacing your home AC.

The challenge of upgrading these systems lies in their complexity. But, upgrading key components in the system can greatly improve its efficiency and be financially lucrative. In addition to the clear financial benefit, upgrades can also help cut down on a building's carbon footprint and help it in green (LEED) certification.


Where to start can be challenging (P6)

What questions do you need to ask?

Where do you start? Understanding and selecting from these technologies require specialized engineering knowledge. We suggest you first ask the following questions to determine if an upgrade is needed.

1. Is there a significant difference in the occupancy levels of the building                  between peak and off-peak hours?

This is usually the case for commercial buildings. If there is a 30-70% difference, upgrading your a chiller compressor and water pumps to those with variable frequency drives (VFD), could result in significant energy savings.

2. Are there particular areas of the building that experience a high variance in          their occupancy over the course of the operating day?

This is generally the case for cafeterias and building lobbies. And installing an Air Handling Unit (AHU) with a VFD in these areas will help you reduce energy wastage in these areas and save on your cooling costs.

3. Is the continuous functioning of the air conditioning system critical for the            building’s operations?

Your chiller system can be connected to a Building Monitoring System (BMS) to continuously monitor key variables. This will enable maintenance engineers to identify potential problems before they impact the system’s operations.

4. Are the maintenance costs for the system high?

A Building Monitoring System (BMS) will also allow you to centralize the monitoring and troubleshooting of your system. This will help you cut down on personnel, spare part, and system downtime costs.

5. Is the refrigerant you use scheduled to be phased out?

Hydrochlorofluorocarbons (HCFCs) are commonly used refrigerants that have high ozone-depleting potential. Many of them are being phased out, including R-22 and R-141b which have depleting potentials of 0.055 and 0.11, respectively. The phase-out is part of the Montreal Protocol signed by 197 countries including Sri Lanka. However, refrigerants like R-22 are being replaced by R-410A which are non-ozone-depleting and do not have a phase-out date.

If your answer is yes to one or more of the questions above, an upgrade to your chiller system should be considered. To better understand the workings of your chiller system and its components, you can check out our articles here.  

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