A chiller is a machine designed to cool down water, or water / glycol solution to a precise temperature using a refrigeration circuit.
Chillers are commonly used in industries such as food processing, data centres and manufacturing to regulate temperatures effectively. They are essential to operations that require consistent and reliable temperature control to secure the quality and stability of products and processes.
Our chillers work on the principle of the vapour compression cycle. There are two types of chillers, either air cooled, or water cooled. Read our full blog to read more about these technology types as well as the vapour compression cycle.
Types of Chillers and Their Mechanisms
Air-Cooled Chillers: Air cooled chillers use air that is passed through the condenser by the use of fans to extract heat from the condenser.
Water-Cooled Chillers: Water cooled chillers use a secondary water circuit that is pumped through the condenser to remove heat from the condenser.
Now let’s look at the vapour compression cycle...
- The chiller pumps water, or water / glycol solution to the process application where heat is extracted from the application into the cooling fluid that then returns to the chiller. The chiller has a refrigerant circuit that consists of four main components: evaporator, compressor, condenser, and thermostatic expansion valve (TEV).
- The evaporator is a heat exchange device that absorbs the heat from the cooling fluid into the refrigerant and causes the refrigerant to evaporate and become superheated vapour.
- This superheated vapour at low evaporating pressure is then compressed by the compressor into superheated vapour at a higher condensing pressure.
- It then enters the condenser, rejects the heat at high pressure, whilst desuperheating and condensing into a high-pressure liquid. The condenser is another heat exchange device and the rejected heat from the refrigerant is absorbed by the air (air cooled chiller) or water (water cooled chiller) that passes through the condenser.
- Expansion of the refrigerant then takes place at the thermostatic expansion valve and the high-pressure liquid lowers to an evaporating pressure liquid and enters the evaporator completing the cycle.
- Through this process, the cooling fluid is continually cooled and returned to the process application at the required temperature set point due to the correct staging of the compressor and modulation of cooling across the condenser.
How Do Chillers Work?
Chillers operate using a refrigeration cycle, consisting of 4 key steps:
- Compression: The compressor raises the refrigerant gas’s pressure and temperature, initiating the cooling process.
- Condensation: The high-pressure gas moves to the condenser, where it releases heat through a heat transfer process and turns into a high-pressure liquid. During this phase, the refrigerant condensing temperature is a critical factor in determining the efficiency of the heat exchange.
- Expansion: The liquid refrigerant then passes through the expansion valve, causing a drop in pressure and temperature.
- Evaporation: This low-pressure liquid enters the evaporator, absorbing heat from the surroundings and converting back into a low-pressure gas. The cycle then repeats.
Key Components of Chillers
Compressor: The heart of the chiller, it compresses the refrigerant, increasing its pressure and temperature.
Condenser: This component allows the high-pressure gas to release heat and condense into a high-pressure liquid. The refrigerant condensing temperature is crucial here for efficient heat transfer.
Expansion Valve: It reduces the pressure of the liquid refrigerant, causing it to cool down.
Evaporator: Here, the refrigerant absorbs heat from the process water or air, cooling it down before returning to the compressor to repeat the cycle.
Benefits of Using Chillers
Energy Efficiency: Modern chillers are highly energy-efficient and can significantly reduce operational costs.
Consistency and Reliability: They provide consistent cooling, which is crucial for processes that require precise temperature control.
Flexibility: Chillers come in various sizes and configurations, making them adaptable to different needs and environments.
Longevity: With proper maintenance, chillers can have a long operational life, providing reliable cooling for many years.
Applications of Chillers in Industry
Industrial chillers are required in various industrial settings, providing effective cooling solutions for operations in manufacturing, pharmaceuticals, and chemical processing. By removing excess heat, an industrial chiller helps preserve product quality and enhance operational efficiency. They are critical for controlling the temperature of equipment and machinery in demanding environments. For instance, in plastic manufacturing, chillers cool the hot plastic that is injected, blown, extruded, or stamped.