Introduction to Commercial Refrigeration Systems : Compressors

 Four Most Common Types of Compressors:

1. Reciprocating Compressor:

   • Operation: Uses a piston driven by a crankshaft mechanism.
     • Crankshaft turns, piston lowers, suction valve opens, refrigerant vapor fills the cylinder.
     • Piston rises, compresses gas, discharge valve opens at high pressure.
   • Applications: Used in small and medium-sized systems.
   • Advantages: Inexpensive design.
   • Disadvantages: Inefficient compared to other compressor types.

2. Rotary Vane Compressor:

   • Operation: Rotating element (rotor) inside a cylinder with a vane that compresses vapor between the vane and cylinder walls.
     • Volume of vapor is reduced, increasing pressure.
     • All refrigerant leaves through the discharge port.
   • Advantages: Few moving parts, smaller size, low cost, reduced maintenance costs, high pumping efficiency.

3. Scroll Compressor:

   • Operation: Has two interwoven scrolls; one orbits the stationary scroll, trapping and compressing gas pockets.
     • Pockets become progressively smaller, reaching highest pressure at the center before discharge to the condenser.
   • Applications: Suitable for medium-sized applications.
   • Advantages: Few moving parts, high pumping efficiency.
   • Disadvantages: More expensive than other compressor types.

4. Screw Compressor:

   • Operation: Two meshing screws (male rotor and female rotor) trap refrigerant vapor, reduce its volume, and increase pressure.
     • Compressed vapor is discharged from the end of the grooves.
   • Applications: Largest capacity, suitable for larger applications.

Key Considerations for Businesses:

• Factors: Efficiency, costs, reliability, and ease of maintenance.
• Compressor Selection: Must have the capacity to move refrigerant throughout the system, chosen based on specific business needs.