Different types of process chillers fall under two main categories: (1) Vapor Absorption and (2)Vapor Compression. Vapor compression chillers are the most common and include (1) air chillers and (2) water/fluid chillers. Chillers are further categorized by the type of compressor technology used: (1) centrifugal, (2) scroll, (3) reciprocating, and (4) screw.
Chiller units are refrigerant systems that aid in cooling residential/commercial spaces, machines, industrial operations, and industrial chemicals. These units are energy efficient, cost-efficient, and time-efficient. Without these systems, production objectives often cannot be achieved.
Chillers fall under two main categories: vapor compression and vapor absorption chillers. vapor compression chillers use an electrically driven mechanical compressor to force a refrigerant around the system while vapor absorption chillers use heat to move the refrigerant around the system.
Vapor compression chillers are the most commonly used and fit into two subcategories: air chillers and water chillers. Let’s take a quick look at how each of these work, their applications, and the pros and cons of each.
How Air Cooled and Water Chillers Work
Both air and water chillers have the same components: an evaporator, a compressor, a condenser and an expansion valve. Furthermore, the mechanics for both are very similar. The compressor pushes a refrigerant around the inside of the chiller through the condenser, the expansion valve, the evaporator, and back to the compressor.
(Read more about how chillers work here.)
The primary difference between air and water chillers is how the unwanted heat is ejected. Air chillers us air to remove heat while water chillers use, you guessed it, water.
Air cooled chillers use air to remove heat by using fans to force air across the exposed tubes of the condenser. While air chillers require more energy than water-cooled chillers, they can be a great option when it comes to stationary cooling. Air chillers are easy to instal and typically can be installed outside a building (no extra space requirements). Compared to water chillers, air chillers are more prone to blockages and recirculation issues.
Water chillers remove heat by pumping water through a sealed condenser and dispersing it through the cooling tower. Water-cooled chillers are typically more efficient than air-cooled chillers. Using water evaporation to dissipate heat uses significantly less energy than blowing air across a hot surface. This is thanks to water’s high heat capacity. Additionally, water chillers tend to last longer than air-cooled chillers.
Types of Compressor Technology
Air-Cooling and Water-cooling chillers are further categorized by the type of compressor technology used.
The majority of centrifugal chillers are water chillers (It’s extremely rare that you’ll find a centrifugal system in an air chiller). Centrifugal chillers are often used for medium to large cooling loads (typically available from 150 up to 6,000 tons of refrigeration) This system offers high cooling capacity in a compact design. Centrifugal chillers operate by using rotating impellers to compress the refrigerant and force it around the chiller.
These systems work by using a piston and chamber to compress the refrigerant. You’ll find a reciprocating compressor in any of the ½ ton models we sell at North Slope Chillers.
Scroll Compressor Chillers
Scroll compressors are used in both air and water coolers. These chillers operate by using two spiral plates (one stationary and one rotating) to compress the refrigerant. Our chillers use scroll compressors for the 1 and 2-ton models.
Screw Driven Chillers
Screw chillers are also used in both water and air chillers and are best for small to medium cooling loads. These chillers are typically available in 70 to 600 tons. Screw compressors work by using two interlocking rotating helical rotors to compress the refrigerant.
North Slope Chillers are portable water-cooling chillers; they offer all the energy-efficiency and quick cooling of water chillers without intensive installation or bulky towers. If you need help determining which chiller type is best for your needs or would like to learn more about how North Slope Chillers work, shoot us an email at [email protected].