If you are currently in the industrial chiller market, you have probably noticed that different chiller units have different compressor types. You may be wondering what the details of these different compressors are. Having a basic understanding of the core mechanisms of your unit not only provides you with a better appreciation for the unit, but also helps in your general maintenance and troubleshooting efforts.
Compressors are vitally important to the overall chiller system. They take in low-pressure refrigerant vapor from the evaporator and compress it. The resulting hot, high-pressure gas is discharged to the condenser. Once cooled in the condenser, the refrigerant continues through the expansion device and enters the evaporator. There, it chills the process fluid. Without a working compressor, the refrigerant cycle simply cannot function.
Chase Chillers feature four different types of positive displacement compressors: reciprocating, rotary vane, scroll, and screw. The compressor type largely aligns with the size and capacity of the chiller itself. Continue reading below for more information on the basics of the different compressor types.
Reciprocating Compressors
Reciprocating compressors use a piston and cylinder to compress incoming refrigerant. As the piston moves downward, refrigerant is drawn into the cylinder. The piston then moves upwards compressing the refrigerant and discharging it downstream to the condenser. Intake and exhaust valves ensure that the refrigerant does not flow backwards. These types of compressors are very economical and efficient in smaller applications. As with rotary vane and scroll compressors discussed below, reciprocating compressors consist of a hermetically sealed design. Chillers set up for small to medium heat loads, such as QBS and some QBE models match well with this type of compressor.
Rotary Vane
Rotary vane compressors typically are quieter than other options. They consist of vanes or blades that are attached to a core rotor. The rotor is positioned off-center within its cylinder, creating multiple areas of varying sizes. The refrigerant enters the cylinder at the largest of these areas. As the rotor turns, the fluid is forced into smaller areas and compresses. Once compressed, the fluid exits the cylinder and continues through the rest of the system. Typically, industrial chillers with this compressor type only contain one compressor per unit. This compressor type is available in certain QBE models and the smallest CWT model.
Scroll
The most common compressor type in industrial chillers is the scroll. It is a powerhouse of a design and is able to handle significantly larger loads than the other compressor types. Found in our larger units, CWB, CWE & CWT, scroll compressors work by compressing the refrigerant between two spiral plates, one stationary and one orbiting. As the spirals move in an offsetting pattern, the trapped air is forced into smaller spaces as it moves towards the center. The compressed fluid exits through the center outlet and into the rest of the system. Multiple scroll compressors can be used in a single cooling unit, a feature great for building in redundancy and providing highly efficiency partial loads. With fewer moving parts, they are often more reliable and efficient than reciprocating options.
Screw
Rotary screw compressors have two interlocking helical rotors mounted inside a casing. As the rotors turn, the gas is forced from the suction end of the casing to the discharge end. The available space between the rotors and the casing becomes increasingly smaller as the gas moves along the length of the screw, increasing the pressure. Screw compressors are useful for varying the cooling output and are found in the largest chiller units. This design is able to limit how much refrigerant is delivered and lends itself well to meeting the variable needs of some cooling processes. Chillers in the CWV series have this compressor type.
The chart below outlines which compressor type is present in which Chase Chillers model:
| Reciprocating | Rotary Vane | Scroll | Screw | |
| QBS | ✔ | |||
| QBE | ✔ | ✔ | ✔ | |
| CWT | ✔ | ✔ | ||
| CWE | ✔ | |||
| CWB | ✔ | |||
| CWV | ✔ |
Regardless of which unit you choose, you can trust that it will be backed by the Chase Cooling Systems quality assurance. Each compressor type has its perks and benefits certain systems over others. To make sure you have the best unit for your system, work with one of our cooling experts. They are available for consultation regardless of where you stand in the buying process. We want you to find the best fit for your needs. Our years of experience and knowledge make us a strong resource for this process.