Types Of Chiller Systems
If you are searching for Types Of Chillers, this post should help! Industrial chillers are an integral part of keeping large commercial buildings comfortable during the warmer months. They typically work in conjunction with a cooling tower which helps reduce the overall temperature of the cooling system. There are two main categories of chillers, these are air and water chillers.
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- Types of Chillers
- Air Chillers
- Water Chillers
- Evaporative Condensed Chillers
- Chiller Subcategories
- Reciprocating Chillers
- Rotary Screw Chillers
- Centrifugal Compression Chillers
- Absorption Chillers
- Where Are Chillers Used?
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Types Of Chillers
There are 3 types of chillers that cool things using air, water, and evaporation. Each type may have subcategories based on how each of them accomplish this goal. Technology varies and depending on the age of the building you own or manage the type of chiller you have may fit into one of the following categories.
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- Air Chillers
- Water Chillers
- Evaporative Condensed Chillers
- Reciprocating Chillers
- Rotary Screw Chillers
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- Centrifugal Chillers
- Frictionless Centrifugal Chillers
- Screw Driven Chillers
- Absorption Chillers
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Air Chillers
Air chillers can be split in various configurations or used as a single piece unit. Air chillers vary in size from small capacity to 100+ ton models that are used to cool commercial buildings. The difference between air cooled and water cooled chillers is that air chillers use ambient air as the condensing source and a fan that moves the air over the coil. Water chillers on the other hand use water as the condensing source and a pump that circulates water through the condenser out to the cooling tower that releases it into the atmosphere.
Water Chillers
Water chillers are mechanical devices/refrigeration systems that are used to dehumidify air and cool fluids in industrial and commercial facilities. They have many applications from process use to space cooling. The difference between water and air chillers is that the water is sent to a cooling tower to cool the water in a water chiller.
Evaporative Condensed Chillers
An evaporative condensed chiller is an alternative to water and air condensed chillers. Most evaporative condensed chillers range from 15-200 tons but one should select a system that is best suited for their individual facility. Maximizing heat rejection in evaporative chillers is done by recalculating the water constantly to provide on-going wetting of the condenser tubes while mechanical fans pull the air over them, which evaporates the water and rejects the heat to the atmosphere.
Sub-Categories Of Chillers
These chillers are sub-categories of the main 3 types of chillers: reciprocating, rotary screw, and absorption chillers. Each have their own design and pro vs. cons. Choosing the right chiller for your facility is an important decision. It will decide how well you are equipped to take care of your industrial process or use the chiller as part of your HVAC system in a commercial building.
Reciprocating Chiller
Gas is compressed inside these types of chillers with pistons, not unlike a car engine. There are multiple pistons that continue to compress the gas to heat it. The difference is that the hot gas is used inside the system, not simply exhausted out of a tailpipe. The demand is matched by the adjustable intake and exhaust valves that can be opened to allow the piston to simply idle. Idling the piston when demand for chilled water helps manage capacity. This system is very flexible and can cope with the specific demands from load on the system. It is also possible to manage the capacity to match the demand with a hot gas bypass, but it is not considered to be as efficient. Some systems use both capacity control systems which unload pistons but also utilize the hot-gas bypass to match demand.
Rotary Screw Chillers
The screw compressor is also known and a helical compressor. Inside the stationary housing it contains to mating helically grooved rotors. Direct volume reduction is achieved when the helical rotors rotate. The capacity of a rotary screw compressor varies between 20 and 450 tons and is controlled by a sliding inlet valve or variable speed drive.
Centrifugal Compression Chillers
One of the main features of the centrifugal compression chiller is that they offer a high cooling capacity in a compact design. They operate via an impeller, much like a water pump. The impeller compresses the refrigerant. These chillers can be outfitted with both variable speed drives and inlet vanes which are used to regulate the control of the chilled water capacity. These are high capacity and can handle 150 tons and up.
Frictionless Centrifugal Chillers
Much like the regular centrifugal design these operate via the same principles but do so with magnetic bearings. The use of magnetic bearings eliminates the need for lubricant and features variable speed DC motors. These motors are typically direct drive and attached directly to the chillers. The capacity of these chillers range anywhere from 60 to 300 tons.
Absorption Chillers
Instead of utilizing a mechanical compressor the absorption chillers use a heat source to be the driving force behind the refrigeration cycle. These chillers typically use two liquids, one to cool and one to absorb. The absorbent liquid is usually ammonia or lithium bromide, and the coolant is usually water.
The two liquids are separated and recombined during the absorption cycle. Due to the low pressure conditions in the chiller water can change phase easily. Water and the absorption liquid also perform well in chillers because of their natural properties of affinity.
The refrigeration cycle starts with the heating of the combined liquids. This boils the water out of the absorption liquid at a high pressure. The next step is sending the refrigerant water vapor past a condenser coil where the heat is rejected and the water vapor is phased into a high pressure liquid. Then the high pressure liquid is passed along to the lower pressure evaporator where adiabatic flash evaporation returns the water to a gas. This absorbs the heat from the water that needs to be chilled. The last step is the concentrated absorption liquid is sent back to be recombined with the lower pressure water vapors coming from the evaporator.
Where Are Chillers Used?
In the industrial world there are millions of machines which generate incredible heat. For these machines not to overheat and melt themselves they must be cooled. This is what a chiller is designed to do. Chillers are used for processes that operate at 60°F or lower. For processes which operate at 85° or higher cooling towers are a better fit. Listed below you’ll find some of the common areas in which chillers are used:
HVAC Systems
Cooling systems are more than just a matter of comfort in Arizona, they are matter of health and safety. For commercial locations cooling expenses typically make up about 30% to 50% of the energy costs. With the cost of electricity always on the rise and the phasing out of HCFCs and CFCs there is an incredibly high demand for replacing large commercial air conditioning and refrigeration systems with chilling systems.
Plastic Fabrication
Chillers used in plastic fabrication typically take on one or both of two roles, cooling the plastic products and cooling the machinery used to make them. The products which are blown, stamped, or extruded. The chiller units are also used to keep the barrel of the extruder, and hydraulics of the molding machine cool. This not only saves on energy but it also helps extend the life of the plastic fabrication equipment.
Medical Facilities
Medical facilities, especially those which do MRIs, laboratory testing, scanning, and blood cooling all rely on chillers to get the job done. The scanning equipment such as MRI machines produce a lot of heat that must be dissipated quickly and safely to preserve the condition of the equipment.
Printing Houses
Chiller play a critical role in high volume printing houses. There is a lot of heat generated by friction through the printing rollers and as ink is dried in ovens. To keep the rollers in good condition and freshly printed paper in good condition chillers are used. They remove the heat from the process and keeps the parts and paper in good condition despite the high heat conditions.
Beverage Industry
A common step of many types of beverage production is cooking, mixing, and pasteurizing. Whether its soda, beer, milk, or other drinks the beverage industry relies on chillers to remove heat produced by these processes.
Laser Applications
Lasers are fast becoming a more common element of production, and one that produces a lot of heat. To keep the lasers and products they cut cool chillers are integrated into these systems.
Rubber Fabrication
The rubber industry relies on chillers to cool the multizone water temperature control units. This keeps the rubber mill, rubber extruder barrel, bambury mixers and calendars cool and working properly.
Where Are Chillers Installed?
Chillers are usually located in mechanical rooms where other industrial equipment is installed. In other cases the chiller may be outdoors or between the cooling tower and process that requires chiller. This usually depends on the application, the size, and type of chiller and the compressor. No matter where they are they will need regular chiller maintenance to operate efficiently. All Kote Lining, Inc. offers full service cooling tower and chiller maintenance to locations all over the Phoenix Valley.
Phoenix Valley Chiller Repair & Maintenance
All Kote Lining Inc. does far more than just apply protective coatings to your chiller tubes, chillers, and cooling towers. We service and repair chillers in the Phoenix area. We can help you get the most out of your commercial HVAC system by helping maintain the cooling tower and the chiller systems to ensure they are performing their best, and using as little energy as necessary. Give us a call today if you need repairs or service on your chiller system.