The chiller system essentially provides cooling through a cycle in which a special refrigerant circulates through the compressor, condenser, expansion valve, and evaporator.
The hot gas entering the compressor is compressed and turned into a very hot liquid. It is cooled by the condenser and converted into a hot liquid; then, as the liquid passes through the expansion valve, its pressure—and consequently its temperature—drops, and it turns into a cold gas. In the evaporator, it absorbs heat from the cooling water via a heat exchanger, warms up, and is sent to the condenser to be compressed again, completing the cycle.
The cooling water is cooled by the evaporator; the cooled water is then distributed to the areas requiring cooling via units such as AHUs, Funcol, etc., providing cooling, and then returns to the evaporator system to complete the cycle.
Excess heat from the fluid exiting the compressor is dissipated into the air or water via the condenser. If the heat is dissipated into the air, the system is called an air-cooled chiller; if it is dissipated into water, it is called a water-cooled chiller.
Chiller systems are generally divided into two categories: water-cooled (open-type cooling tower – closed-type cooling tower) and air-cooled chillers.
In addition, heat pump chillers, 4-pipe chillers, and free-cooling chiller systems are also used.
Air-Cooled Chiller
It works by having the refrigerant gas inside the chiller release the energy it gains through the evaporator and compressor via the air-cooled coils.
The extremely hot fluid compressed by the compressor is sent to the condenser. Heat transfer occurs as air flows over the coil surface with the help of fans. Cooling is completed as the heat from the gas is transferred to the air.
Water-Cooled Chiller
Unlike air-cooled chillers, water-cooled chiller systems cool the very hot fluid in the condenser circuit using water via a heat exchanger. Water sources for the cooling water can include rivers, groundwater, seawater, a cooling tower, or a standard water supply line.
It is important to note that water-cooled chiller systems minimize the unit’s volume, resulting in a unit that is 65% smaller than a chiller of similar capacity. At the same time, due to improved compressor performance, they consume less electricity and deliver high performance; of course, water consumption does occur.
Chiller systems are used primarily in industrial production facilities, as well as in the food and pharmaceutical industries, plastic manufacturing plants, cosmetics manufacturing facilities, cold storage warehouses, hotels, and hospitals. However, a chiller system must be custom-designed for each specific application.