What Is a Refrigerator Compressor?

The refrigerator compressor is one of the four main components located inside your fridge that makes your refrigeration system work. The compressor works directly with the condenser and evaporator coil, along with the expansion valve. Your refrigerator's compressor controls and compresses the flow of liquid refrigerant, playing a crucial role in your refrigeration system. Compressors fundamentally work the same for air conditioning systems, but will differ in some big ways, and this article focuses on how a refrigerator compressor works.

Refrigeration compressors act as the heart of the refrigeration cycle. To begin the refrigeration cycle, the evaporator takes refrigerant in a liquid form, and converts it into a low pressure gas. The compressor's job is to receive this lower pressure refrigerant gas from the evaporator and convert it into a higher pressure gas. When this high pressure gas gets compressed, it generates a lot of heat, increasing the pressure and temperature inside the compressor. This high pressure gas moves into the condenser where it condenses back into a liquid, giving off more heat as the cooling cycle begins in your refrigerator. This newly converted liquid refrigerant then moves into the expansion valve, which provides and controls the flow of refrigerant in a low pressure liquid form.

At this point, you may be asking yourself "Ok I know how my refrigerator compressor works, but what type of compressor do I need? Will this refrigeration compressor work with my fridge? Which commercial refrigerator do I need?"

What are the types of refrigerator compressors?

Refrigeration compressors are one of the main components in your fridge, so choosing the right one is essential for keeping a cold air temperature in your fridge. But what is the difference between reciprocating, centrifugal, and rotary compressors?

Reciprocating compressors

One type of compressor is a reciprocating compressor. Reciprocating compressors use a piston-based operation, similar to a combustion engine. As the piston moves up and down, refrigerant from the evaporator will pump in, and as the temperature and pressure increases, compressed refrigerant gas flows out of the compressor into the condenser.

Centrifugal compressors

Another type of refrigeration compressor is the centrifugal compressor. Centrifugal compressors take refrigerant in the liquid form, and converts the refrigerant into kinetic energy by spinning it through a rotating impeller. As the speed of the impeller increases, the kinetic energy will heat up the temperature of the refrigerant, converting the liquid into a refrigerant gas. Temperature sensors inside the compressor will then release and pump this high pressure refrigerant gas over to the condenser, beginning a new cycle of cooling.

Rotary-vane, Rotary-screw, and Rotary-scroll compressors

Rotary-vane compressors utilize a rotating drive shaft with vanes that split it into suction and discharge sections. Pistons rotate to both increase and decrease volume between the sections, allowing for continuous pressure buildup and release as it spins.

Rotary-screw compressors use two male and female rotors spinning in opposite directions, trapping, and compressing refrigerant between the rotors as air travels through.

Rotary-scroll compressors use fixed and orbiting scrolls to suck pockets of refrigerant into the center where it gets compressed WITHOUT the use of pistons.

Top Mounted vs. Bottom Mounted Compressors

Refrigerators can have compressors mounted onto the top or the bottom. Top-mounted compressors are best for dry storage areas where the floor can become dusty and covered in spilled ingredients. Bottom-mounted compressors are best for hot areas and line cook applications.

Top Mounted Compressor

Pros:

• Does not need to be cleaned as often
• Energy efficient
• Ideal for cooler environments
• More top storage
• Refrigerants don’t have to run through the back as all of the components are in the same place
• Tend to last longer and require fewer service calls

Cons:

• Harder to get to for maintenance which can increase repair cost.
• Hot air released can be hazardous for low ceilings
• Higher initial cost

Bottom Mounted Compressor

Pros

• Higher bottom shelves
• Easier to access, making maintenance and cleaning easier
• Ideal for warmer environments
• Low initial cost

Cons

• Compressor are likely to get dirtier more frequently.
• Refrigerant runs from the bottom to the top through the back of the fridge, eliminating some storage space

Bottom mounted and Top-mounted compressors offer great benefits for any commercial kitchen application. Be sure to pick the one that best fits your needs to maximize the benefits.