Air cooled or water cooled chiller, which is suitable for my case? This is a question put in front of many people. Here we will talk about the differences between them from these aspects: performance, installation, maintenance, and cost.
Air cooled chiller is with aluminum fin type condenser, which allows it to discharge the heat to the air. In other words, the heat is removed by the ambient air.
Water cooled chiller is normally with shell and tube condenser. The heat from the chiller is removed by water that goes into and out from the condenser.
As we know, for a chiller, if you can get lower condensing temperature, you can have better performance. Actually, the difference of condensing temperature is the reason of different performance between water cooled and air cooled chiller. In our daily life, if we want to cool down something, for example, a glass of hot water, do you prefer putting the glass in a container with cold water or put it in front of a fan? The answer is easy, we prefer to cool object with water, as water has larger specific heat value and lower temperature than ambient air most of the time.
When it comes to a chiller, the common sense is still applicable. With the water-cooled condenser, a water-cooled chiller can get lower condensing temperature than an air-cooled chiller.
Here comes the result, for same model size, a water-cooled chiller has relevantly better performance than an air-cooled chiller.
Air cooled chiller needs an open and drafty space, so the heat exhausted from it will not stay around. If the hot air stays around, the performance will get lower and lower, even cause the shutdown of the chiller.
On the contrary, water cooled chiller has no strong requirement for ventilation, because its heat is discharged by the water.
Condenser size of air-cooled chiller is large, as it needs larger heat transfer surface of the aluminum fin, and fans to make the air flow. While water-cooled condenser can manage the same heat transfer task with much smaller size.
The size of condenser decides that dimension of an air-cooled chiller is bigger than a water-cooled chiller.
c. Piping and connection
For an air-cooled chiller, we need to do the piping between the chiller and the object to be cooled only. But for a water cooled chiller, we need to do two more step, that is to install a cooling tower, and connect the chiller condenser to the cooling tower.
It is commonly known that chiller performance will drop down without proper maintenance. Here we are talking about the cleaning of the condenser, if condenser’s heat transfer surface is dirty, the performance of chiller will be seriously harmed.
For an air-cooled chiller, the dust-covered on the condenser is visible, you can easily know when to clean it. The cleaning of an air-cooled condenser is quite simple, you just need to remove the filth from it with water and non-corrosive additive. For an water cooled chiller, you can not see if there is something wrong with the condenser. Cleaning of water cooled condenser needs professional devices, and it is not so convenient as well.
As far as unit cost is concerned, an air-cooled chiller is more costly than a water-cooled chiller.
But the comparison needs to be comprehensive. As we know that water cooled chiller needs a cooling tower to work together, which is extra cost comparing to air cooled chiller. With the cost of the cooling tower, the cost difference between them is smaller. On the other hand, we also need to consider the maintenance cost. In this aspect, air-cooled chiller has an obvious advantage.
In short, both air cooled and water cooled type chiller have their own advantages. When we talk about that, we need to consider our own conditions, so to make the right choice.