First thing first: How to cool the chiller?
There are several types of industrial chiller that are most commonly used in the market. For the sake of easier understanding, we normally refer to 2 main types of industrial chiller namely air-cooled and water-cooled.
As we all know that chiller is to produce cold water supply (mostly at 7°C) to cool down machines or for air-conditioning purpose. Which suggests that the medium used is water on the evaporator side of a chiller. All the heat energy from load will be carried by the water and transfer over to the evaporator.
According the laws of thermodynamics, the energy can not be created nor destroyed, hence all the heat energy from load transfer to evaporator need to be handled or disposed to somewhere. For this purpose, the condenser of industrial chiller comes into play, to dispose the heat, through air, or through water.
Air-Cooled Industrial Chiller
As the name suggests, the industrial chiller is cooled by air. By forcing air flowing through the condenser and carry heat energy away by convection. Basically is the same as we use a fan to blow directly onto something hot to cool it down, no rocket science at all. All these are achieved through a fan mounted heat exchanger (be it microchannel or tube-and-fin) where the heat energy carried by superheated refrigerant transferred to the ambient air.
Air-Cooled Chiller normally comes as standalone compact package which the condenser with fan will sitted on the top part of the chiller. It is much more space-saving, easier to install, lighter compared to water-cooled chiller. But it is less efficient and for the low capacity chiller range from 10TR to 500TR only.
Water-Cooled Industrial Chiller
This is a big guy compared to the air-cooled chiller. For a water-cooled chiller, it utilizes water as the medium to transfer the heat energy out from the condenser side. The heat-exchanger will be much bigger (compared to air-cooled chiller) and similar to the evaporator, mostly shell-and-tube.
Once the water carry the heat out from the condenser, it will go to another heat-exchanger. This heat-exchanger allow water to dispose the heat to the ambient air effectively, which is known as a cooling tower. The reason for this is because the heat energy being transferred out from the load is so tremendous. It won’t be logical to air-cooled the condenser directly due to the specific heat capacity of air is way too low compared to water.
Specific heat capacity means the max amount of heat energy that can be carried by a unit of air/water. With higher heat capacity, it is the best candidate to be the intermediate medium to carry heat from condenser of chiller before dispose it to the ambient air through cooling tower.
However, despite water-cooled industrial chiller is of very high capacity but it is more complicated(need extra water piping circuit to cycle through cooling tower) and require more space.