How to Improve Chiller Efficiency?

Chillers are among the most widely used cooling systems in both building and industrial installations. They are used to cool the circulating water in HVAC systems or industrial processes. Given the importance of chillers in buildings and industries, a significant portion of installation costs is allocated to them. Improving the efficiency of these systems can lead to cost savings. Several methods and parameters can enhance chiller efficiency. Stay with the following to review ways to increase chiller efficiency.

Raising the Evaporator outlet Refrigerant's Temperature

The compressor is the component that consumes the most energy in a chiller. It receives low-temperature, low-pressure refrigerant from the evaporator and compresses it. This compression increases the refrigerant’s temperature and pressure before it is transferred to the condenser for cooling.
By reducing the temperature difference between the evaporator and condenser, energy consumption decreases and overall efficiency improves. To do this, the refrigerant leaving the evaporator can be preheated (e.g., using a heat exchanger) before it enters the compressor, reducing the work needed for compression. This improves compressor performance and enhances mini chillers and chillers' efficiency.

The Impact of Condenser Type on Chiller Efficiency

As you may know, condensers dissipate refrigeration system heat using either air or water. In air-cooled condensers, fans transfer the heat to the atmosphere. In water-cooled systems, heat is removed via a cooling tower using water. Water is sprayed over the tower's packing, transferring heat to the air and cooling the water. Water-cooled chillers consume less energy and have much better heat transfer rates. Therefore, the efficiency (COP) of water-cooled chillers is higher than air-cooled ones.

Condenser and Evaporator Design

The design of the condenser and evaporator can significantly increase the efficiency of air-cooled chillers. Some examples include:

• Replacing standard fin-tube condensers (copper coils with aluminum fins) with Microchannel condensers

• Using 3-pass evaporators instead of 2-pass ones

• Using flooded-type evaporators instead of conventional ones

• Using evaporators with inner grooved coils to boost heat transfer capacity

The Role of Inverter Systems in Boosting Chiller Efficiency

Since chillers often operate at part load, it's better to use variable speed compressors (VSD or VFD). This allows energy consumption to match the cooling demand, increasing efficiency. This also applies to condenser fan motors. By using variable speed fan motors, chiller energy consumption can be further reduced.

Modular System Design and Chiller Efficiency

Sometimes, instead of having a single refrigerant circuit, a chiller may have 2 or 4 separate circuits. This is called a modular chiller. For example, a 20-ton chiller might use two 10-ton circuits or four 5-ton circuits. If only 10 tons of cooling are needed, only one or two circuits will operate. This load-based operation significantly improves efficiency and reduces energy consumption.

Utilizing a Free Cooling System

In addition to the aforementioned methods, advanced technologies such as free cooling can further improve the efficiency of air-cooled chillers. Free cooling enables industrial cooling or HVAC systems to use cold outdoor air during fall and winter for cooling, bypassing the refrigeration cycle and compressors. This significantly reduces annual energy consumption by turning off compressors during suitable weather conditions.

Chiller Installation Location

The location of chillers installation, for example, DamaTajhiz air-cooled chillers, plays a critical role in optimizing their performance. Wind speed and direction, spacing between chillers, distance from the building, wall height, and wall material can all affect how discharge air is dispersed. Improper conditions can raise the intake air temperature at the condenser, reducing efficiency.

How Chiller Maintenance Affects Efficiency؟

Proper maintenance of chillers helps reduce equipment failures and electricity consumption while extending the unit's service life. Therefore, regular servicing and proper upkeep significantly enhance chiller efficiency. Key maintenance tasks include:

• Periodic cleaning of condenser coils in air-cooled chillers and condenser tubes in shell-and-tube units, as well as flushing the cooling tower in water-cooled chillers.

• Compressor checks by specialists, including refrigerant temperature and pressure (suction and discharge), noise and vibration levels, oil conditions, and crankcase temperature.

• Maintaining optimal refrigerant charge, refilling if required, and repairing any system leaks.

• Water treatment and descaling of pipes to improve heat transfer between water and refrigerant.

• Timely replacement of filters.

• Pump inspection and servicing, including bearing lubrication, ensuring positive suction pressure (if needed), and shaft alignment by certified technicians.

• Inspection and servicing of electrical and mechanical components such as piping, control panels, wiring, and more, by professionals.

• Draining evaporator water from water-cooled chillers during winter to prevent freezing damage.

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Conclusion

This article explored effective ways to boost chiller efficiency. We hope the information provided has been helpful.
You can compare and purchase various chiller models with valid warranties on the DamaTajhiz specialized website. Additionally, the site offers a wide selection of HVAC and heating products, such as air-cooled and water-cooled chillers by DamaTajhiz or other leading brands and in different capacities. Visit DamaTajhiz (the first and most reputable specialized HVAC supplier since 2004 with three valid business licenses) for up-to-date product pricing, or contact our experts during working hours for more information and consultation.

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