Process Cooling Education

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 Chillers

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

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.

Centrifugal Chillers

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.

Reciprocating Chillers

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].

As much as we’d love technology to run at maximum efficiency 100% of the time, regular wear and tear can lead to malfunctions. If your business owns or regularly uses a chiller unit, it could be helpful to familiarize yourself with these chiller repairing and maintenance steps.

When it comes to process chiller repair and maintenance, it is necessary to know and understand how chiller systems work. Here are a few helpful tips that can help keep your chiller running efficiently:

1. Track and Monitor Daily Operations Log

A daily operations log provides supporting data to help isolate problems and fix inefficiencies faster.  Details under the log should include flow rates, operating temperatures, and other crucial information. Keeping a detailed log takes just a few minutes a day and could be the key you need to get things up and running again should a problem arise.

2.Use Regular Water Treatments

There are many different types of chillers used in different situations, but the most common are water chillers, or water-cooled chillers. Water in the units must be frequently treated to prevent corrosion, scale accumulation, and algae growth. For closed water systems use regular chemical treatments. Filters should be cleaned every three months to prevent contaminant buildup.

3. Immediately Tend to Leaks

Small leaks in your chiller system can lead to more serious issues. Unwanted moisture could contribute to the formation of corrosive acids. Additionally, moisture could cause chiller parts to rust and stop working properly. Carefully check your unit at least once quarterly for leaks.

4. Clean System Tubes

Overall system productivity depends upon the efficiency of heat transfer in the evaporator and condenser tubes. Keeping these tubes clean will help keep your chiller running smoothly. Cleanings are done through brushing or applying chemicals to remove algae and scale accumulation.

5. Regularly Conduct Oil and Refrigerant Analysis

Regularly analyzing the oil and refrigerant within your system can help prevent more complicated issues. Consistent refrigerant analysis can help detect contamination issues. Oil analysis can expose underlying problems such as problems with compressor wear or excess moisture content in the oil.

When chiller units malfunction or breakdown, try following these common chiller problems solutions:

• If your pump runs irregularly, check that all valves are open to the chiller. Next, check for possible debris entering the pump. If everything looks clean, check that the pressure is within the normal range. If all looks well there, there could be a possible problem with the pump component that requires professional attention.

• If there’s an irregularity with the switch contact, you can use a simple multimeter to check the contacts of the switch.

• Additional issues will likely require professional attention. If you’ve been experiencing issues with your chiller unit, give us a call at (866) 826-2993.

Replacing Your Chiller Unit

If you’re currently using a chiller unit that you’re unsatisfied with, it may be time to replace it! North Slope Chillers are a top-notch option. If you’d like more information on which North Slope Chiller will best replace your current system, give us a call at (866) 826-2993.