Chiller Working Principle

Chiller Working Principle
A chiller is essentially devices that can take heat from one source and transfer it to another source. Its working principles are the known refrigeration cycle in thermodynamics. It basically consists of compressor, condenser, expansion valve and evaporator. Working principle; The compressed and heated gas in the compressor is cooled in the condenser so that the heat is thrown to the environment. Then, due to the pressure of the gas passing through the expansion valve, its temperature drops and it liquefies. While passing through the evaporator, it takes the heat from the liquid to be cooled, comes to the compressor as a gas at low pressure, and is compressed again. The cycle continues in this way.
TYPES
It is possible to group the chiller groups according to their different characteristics, but the most decisive distinction is what the heat source is. If the heat is thrown into the air, we can diversify it as an air source chiller, and if it is thrown into the water, we can diversify it as a water source chiller. Apart from this, devices can be differentiated according to the hermetic or semi-hermetic nature of the compressor, the characteristics of the refrigerant used, and the type of heat exchanger.
AIR SOURCE COOLING GROUP
This type of cooling group has condenser coils with fans on it. Compressed in the compressor and high temperature gaseous refrigerant is sent to the condenser. Heat transfer takes place by providing air flow on the coil surface with the help of fans. Thus, the heat on the gas is transferred to the air and this type of chiller is called air-cooled.
WATER COOLED COOLING GROUP
There is not much difference with the air source chiller as a working principle. Shell & tube or plate type heat exchangers, which use water instead of air-cooled coils, are used to cool the gas. The water source can be an endless source such as a natural river or lake, but finding such an environment is the best result water cooled chiller groups can be used efficiently with cooling towers.
COMPARATION OF AIR AND WATER SOURCED COOLING GROUP
The biggest differences between devices that use air and water as a source are the environment in which they will work and their energy efficiency. Air-cooled devices are usually located on the roofs of buildings or in gardens, open to the atmosphere, the environment in which the device is located is not important since heat is not released into the air in water-cooled devices. When we look at energy efficiency, the water source chiller is quite efficient compared to the air source chiller. While the air source chiller tries to throw the heat into the air depending on the dry bulb temperature, the water source tries to throw it into the colder water than the air. Therefore, the water source chiller operates more comfortably and efficiently. Another issue is that air-sourced devices become incapable of cooling in very hot climates. In order to throw heat into the already hot air, the condensation temperatures in the devices rise considerably, which causes performance and capacity losses. It is recommended to use water-cooled devices in such hot climates. In terms of maintenance, the air-sourced chiller is more advantageous than water-cooled devices because it is one-piece and has less mechanical parts.