Difference between Water Cooled Chiller and Air Cooled Chiller

In this post, we will learn the difference between water cooled and air cooled chillers.

HVAC is a very vast field and it comprises of many devices. One of the main components in HVAC is a chiller. Chiller is a refrigerant component which is used to cool the temperature of water, air or evaporation. They are used in many commercial and industrial applications.

Chillers are classified into various categories. One of them is based on cooling medium used in condensers. There are two types of that – water cooled and air cooled. In this post, we will see the difference between water cooled and air cooled chillers.

To understand first of all how a refrigeration cycle works, refer to the below article. It will help to then understand the chillers more easily.

What is Water Cooled Chiller?

As the name implies, Water Cooled chiller uses water as a condensing medium. In condensers, water from the cooling tower is used to condense the hot gas coming from the compressor. The remaining refrigerant cycle remains the same. When the final gas reaches evaporator coils, it does heat exchange with a warm medium (water or air) and cools its temperature.

Cooling Tower is a big building that circulates water with chiller condensers. So, you can say it is a facility where unwanted heat dissipates. There is a large fan that feeds the unit with air, which meets the incoming warm water from the condenser. Heat exchange happens between air and water, and the water becomes cooler.  

What is an Air Cooled Chiller?

As the name implies, an Air-cooled chiller uses the air as a condensing medium. Condensing fans are used to condense the hot gas coming from the compressor. The remaining refrigerant cycle remains the same. When the final gas reaches evaporator coils, it does heat exchange with a warm medium (water or air) and cools its temperature.

Outside ambient air is used to reduce the temperature of refrigerant gas coming from the compressor. The incoming fans suck air from outside and allow heat exchange. The resultant warm air is also eliminated outside by the outgoing fans.

Difference between Water Cooled and Air Cooled Chillers

The following are the key points that discuss the differences between air-cooled chillers and water-cooled chillers.

• The main difference is that water cooled ones use humid air (ambient air with water stream), while the air cooled ones use pure ambient air.
• Air cooled ones are cheaper to set as they require no expensive cooling towers. Water cooled chillers are thus comparatively costlier ones.
• Air cooled chillers are easier to operate and maintain as compared to water cooled chillers, where you will also need to attend cooling towers apart from your chiller.
• As water is the main working point in water cooled ones, if there is any issue in water supply or the water is contaminated, then the condensing will be affected. There is no such issue in air cooled chillers.
• The main advantage of water cooled chillers is their size. The cooling capacity is 10-4000 tons, as compared to air cooled chillers which have a capacity of maximum 500 tons. So, if you have a large industrial setup comprising of many chillers, then water cooled is the most preferred option instead of multiple air cooled condensers.
• The lifespan of water cooled chillers is longer than air cooled chillers.
• The efficiency of water cooled ones is higher than air cooled chillers.
• If you see space consumption, then air cooled chillers consume more space as compared to water cooled chillers due to area occupied by condenser fans and the distance it requires to properly come in contact with ambient air temperature.
• Water chillers are less noisy as compared to air chillers which make a large amount of noise; due to presence of compressor and fans in the same area.

In this way, we understand the difference between an HVAC air-cooled chiller and water cooled chiller.