Normally there are two kinds of chillers available-air cooled chillers and water cooled chillers. Both differ from each other owing to a number of aspects such as initial and running costs, size, heat transfer and others.
In general, there are two types of chillers: air-cooled chillers and water-cooled chillers. Many people wonder, out of these two, which one is better. As both of them have their share of advantages and disadvantages, so if it is said, that none of them are perfect. So let us take a look at the differences between two systems.
First varying factor between the two is the cost. Air chiller is less expensive as compared to the water chiller. This is for the reason hat condenser water pumps, cooling towers and other HVAC related components are not required in the air chilling systems but are required in water chilling systems. In addition to this initial cost difference, because of the evaporative condensers and/or cooling towers have key drawback of maintenance and water treatment expenses. Since this running expense is absent in the air chillers, they are ahead of the water chillers in this respect as well. Moreover, at some places, since there is the scarcity of water, the cost of water may also be a big disadvantage.
Usually, the small systems are cooled using the air medium given that the additional requirements and maintenance of the water cooled systems are of the capital intensive nature and are difficult to be made up through the lower operating costs. Large-sized systems are most likely to be chilled using the water medium.
Many people are prejudiced to the water chillers taking account of superior heat transfer features as against the air chillers. The core benefit of the water model is that with water, the film coefficient is 10-100 times greater than with the air. The film coefficient regulates the heat transfer with certain constant temperature difference and area. Moreover, the equipments that are water cooled make less noise as compared to the air cooled systems which are much noisier that can be irritating at times, in particular for the people in the nearby settings.
One more thing to bear in mind is that the water chilling systems usually condense at a lower pressure, on average, than the air chilling systems. This is due to the water temperature being less as compared to the air temperature. The variation between the dry-bulb temperature and wet-bulb temperature results in the exiting difference between the condensing temperatures of air cooled chillers and water cooled chillers.
Space occupied also matters a lot in a few applications. Open spaces such as roofs, parking lot or ground level area below the normal flooring or raised floor. On the other hand, water chillers need cooling towers and mechanical room for installation. Water cooling systems are high on the performance aspect.
