Category Archives: Chillers

Chillers are a critical element in HVAC systems.  Chillers take the heat out of the air and also are implemented in industrial settings to cool down equipment. These tips are designed to help chiller owners and maintenance personnel conduct detailed and reliable maintenance on air-cooled chillers.

Best Chiller Maintenance Tips

The simple fact is that the chiller makes up for a significant portion of your electricity usage, even at peak performance.  If you’ve got maintenance issues it can easily use an extra 10%, which hurts the bottom line.  While technology has improved to remotely monitor chillers and technology has produced more durable and efficient parts, maintenance is still key.

Maintain A Log Daily

Knowledge is power and saving power is a big deal when it comes to chillers.  Recording operating conditions such as flow rates, pressures, fluid levels, and temperatures helps build a useful record of your system.  While it was standard to do bi-monthly checks today’s continuous monitoring technology allows you to keep accurate daily logs that will help you narrow down maintenance issues before there’s a bigger problem.

Condition Your Water

Corrosion and scaling are always a challenge in air cooled chiller systems.  Treating the water in your system helps cut down on corrosion, scaling, and the growth of biological contaminants such as Legionella.  All of these issues can let to a decrease in heat transfer caused by fouling and diminished heat transfer due to build up inside of pipes.  It’s important to continually monitor your chilled water loops remotely and visually inspect them annually.

Clean Heat Transfer Tubes

A big part of the efficient operation of chillers relies on clean heat transfer tubes.  If your system has mud, minerals, algae, or scaling it will coat the inside of the tubes and insulate them.  While insulation is great at keeping heat out of a home in the summer the heat transfer in chillers is the cornerstone of how the system functions.  Neglecting your chiller tube cleaning will end up inflating your operating costs and likely result in additional maintenance and more frequent downtime.

Maintain Refrigerant Charge

Your chiller’s ability to cool relies on having the right amount of refrigerant. To ensure your systems optimal efficient performance make sure you’ve got the right level of refrigerant.  If there is air, moisture, or leaks in your system it will impact it’s performance.  With insufficient refrigerant it will take more electricity for your system to perform the same cooling effect.

Provide Cooler Water

Providing cooler water for the condense improves the chiller’s performance.  It will not have to work as hard to condense the water and will run more efficiently.  In some cases this technique can compensate for problems with coils.  While this does fix the problem it is a temporary solution as the chiller must work harder for the same effect.

Purge Non-Condensables

Chillers function on the principle of condensing refrigerant to cool.  If moisture or air leaks into the system it introduces non-condensable elements into the system that rob it of efficiency.  The percentage can be as high as 7% below the rated performance of the chiller system you have.  When considering how much energy a chiller uses to begin with and extra 7% adds up quickly.

Maintain Appropriate Flow Rate

The rate at which your chilled water flows through the chiller does impact the chiller’s performance.  If it is too slow it lowers efficiency. Too fast and it will cause erosion, vibration, and noise.  It is best to keep the flow rate of your chiller somewhere between three and twelve feet per second. The exact speed will depend on your chiller’s design and the load needed by your location.

Upgrade To Variable Speed Drives

In most cases the chiller motor is the largest draw on electricity in the entire building.  Single speed drives are on or off and cannot adjust for the difference in load the system is running under.  In contrast a variable speed drive saves energy as it can adjust the speed to match the load.  This saves a significant amount of energy in your chiller system. In addition variable speed allows the system to ramp up more smoothly in the case it is turned on in an emergency situation.

Check Oil In Compressor

If your compressor uses oil make sure you send a sample of it for inspection at a laboratory once per year.  Due to the hermetically sealed nature of a close refrigerant system the compressor oil should only be changed if the lab deems it necessary.  If there’s excessive moisture it can point to there being a problem with purging the system effectively.  If the oil is changed ensure the filters are tested and replaced when there are pressure drops. In the case your system uses magnetic bearings and is frictionless your system will not have compressor oil.

Inspect Motors & Starters

You can save energy and downtime if you inspect your motors and starters.  To do so inspect the sensor calibration and safety on the microprocessor controls.  Also take the time to inspect the wiring and connections in your chiller system at common wear points and hot spots. Pay attention to signs of refrigerant leaks and test motors for insulation faults.

When To Inspect Chillers

Chillers should be inspected and maintained at least 2 times a year in areas where they are only used during the cooling seasons, or 4 times a year in areas that cool in all 4 seasons. Quarterly inspection helps your chillers, HVAC system, and cooling towers last longer and run more efficiently.

Maintained Chillers Operate More Efficiently

Using this checklist you can get better performance out of your chiller and cooling system. The better maintained your chiller is the less energy it uses, and that saves you money on utilities.  As the chiller and HVAC system is one of the largest draws of electricity in many commercial, industrial, and medical facilities it is important to inspect, maintain, and repair chillers.  Regular inspection and chiller maintenance will help save money and make the system last longer.

Chiller Maintenance in Arizona

If you have a property such as a commercial building, medical facility, or industrial site that uses chillers for processes or HVAC All Kote Lining, Inc can help you take care of the chiller maintenance you need to keep your energy use down and make your equipment last longer.  We inspect, maintain, repair, and line chillers with the most durable coatings available. Give us a call today to find out what we can do for your company at 480-966-4446.

Taking things for granted is part of human nature. We rarely consider the way everything works and stays working each day when we go about our routines. The ignition fires up our cars, the coffee pot brews up some motivation every morning and we rarely give the things that make our lives comfortable much thought until they aren’t working. This is no different than HVAC systems. A big part of the HVAC system is the chiller, and the tubes that make it work. Understanding chiller tube cleaning helps us keep our chillers working and our buildings cool during the warmer weather in Arizona.

To keep chillers and HVAC systems efficient they need to have regular maintenance and coatings. It is no small task to care for these critical components of the cooling system for large commercial spaces. Coatings help prevent buildup and cleanings kick out deposits that reduce thermal transfer.

Large commercial spaces use a lot of energy and the chiller can be one of the largest consumer of energy. As the price of energy increases, the savings of regular cleaning and chiller coatings increases. Keeping daily logs, making preventative maintenance a priority, and scheduling regular chiller maintenance will keep your overhead costs down.

Key Chiller Tube Cleaning Considerations

Tube Cleaning

The efficiency of the chiller tubes is completely dependent upon heat transfer. Thermal efficiency is limited by buildup on the inside of the chiller tubes. Most large chillers are comprised of literally miles of tubing which helps achieve the heat transfer in the evaporator and condenser. Keeping the tubing clean therefore is the way these critical HVAC components do their job and use less energy. The best way to keep tubes clean is to have planned outages for cleaning, keeping up with water treatment, and having chiller tube coatings which help control buildup.

The efficiency of chillers drop steeply as buildup develops inside the chiller. It is deposited by contaminants in your water that is recycling through your system and by contaminants being brought in from the air cycling through your cooling tower. The contaminants found in your chiller can range from algae, mud, sand and even minerals that develop into scales that all sap the heat transfer.

The percentages of decreased thermal transfer drop quickly even with what seems like thin layers of contaminants. Even a coating as thin as .0045 can drop chiller tube efficiency by as much as 44%.

Water Treatments

Water used in cooling towers and chillers usually comes from local water supplies. This means there can be additives, sand, minerals, and other elements that cause fouling and deposits in chiller tubes. Even the atmospheric conditions around the cooling tower have a significant effect on the quality and contents of the water used in HVAC systems.

This means that there needs to be water treatment in the system to help fight biological growth, scaling, and other deposits. The most contaminated the water the greater need for water treatment and a more frequent and robust water treatment plan.

Chiller Motors & Electrical Components

The chiller motor in your HVAC system is potentially the greatest user of electricity in your entire building. We might obsess about shutting off lights in our homes and offices, but the chiller is responsible for using an enormous amount of electricity to keep our commercial properties cool and comfortable.

Chiller motor maintenance is a critical part of keeping your system efficient and your energy bills as low as possible. The shaft seals, and air vents should be checked and kept clean.  All of the insulation, wiring, and connections should be maintained to keep the system running properly and avoid unscheduled downtime.

Methods Of Tube Cleaning

For the best thermal performance it is clear that regular cleaning and maintenance of the chiller tubes is not optional. It is mission critical and should be carried out on a regular schedule by properly trained and equipped chiller maintenance technicians. There are different methods that these technicians use to get your tubes clean and maintain the thermal efficiency of your chillers.

Chemical Cleaning

One of the older methods of tube cleaning, is has seen a decrease in use in the last decade. Acid solutions are used in chemical cleaning that soften and break down the scale and deposits in the tubes. The acidic solutions are circulated through the tube bundles and help remove the layers of energy robbing debris.

Chemical cleaning does have the advantages of breaking down mineral scale so brushes can effectively remove them, and it can take tubes back to bare metal. It has lost some of its former popularity because it is time consuming, the chemicals are costly, requires increased training, and the chemicals are dangerous and difficult to dispose of.

Rod & Brush Cleaning

The rod & brush method is very similar to the cleaning of a gun barrel. It is probably the oldest type of chiller cleaning. A rod of metal is tipped with a wire or nylon brush that is larger than the tube. The process generally involves flushing the tubes with water, and then forcing the rod and brush through the tubes. After the rod has been pushed through water is sprayed again to remove any debris.

This is a popular method because it is inexpensive, but it does have some disadvantages. It is labor and time intensive. The chiller might be in an area that prevents the longer rods being used. Smaller sections might have to be assembled as the brush is inserted into the tube, adding to the time of the job. Also the bristles on the brush tend to fold down and end up swabbing instead of brushing. Another limitation of this process can be if the tubes brushed first dry and the debris reattaches before the final rinse is completed.

Rotary Tube Cleaners

Using either an air or electric motor these chiller tube cleaning machines include a cleaning tool that uses water and circular motion to help remove debris. A flexible shaft is set inside a plastic casing which directs water directly to the cleaning head. The tools used with these machines include scrapers, hones, brushes, and buffing tools. This combination of tools is what makes the rotary tube cleaners some of the best at removing deposits, including hard scale. The job is done by one operator feeding the shaft through each of the tubes. Best of all it only takes one pass for each tube.

This is one of the most used, and popular chiller tube cleaning types. It is due to the fact that is it one of the most effective cleaning methods paired with the low cost. The process takes little time and uses less consumables that other cleaning methods. It also only requires one technician, only opening one side of the chiller, and is the best type of cleaning for internally enhanced chiller tubes.

Tube Cleaning Guns

As the name suggests this method of tube cleaning features a gun that uses air or water to shoot a projectile through the tubes. These projectiles vary from metal or plastic scrapes to brushes and even rubber bullets.

This is a popular type of cleaning for light deposits and is very fast. With the right conditions tubes can be cleaned quickly, even in a matter of seconds per tube. It does have the limitation when it comes to the type of deposits it can remove. Harder scaling or stubborn deposits are more difficult or impossible to remove with this method. It also requires the opening of the chiller on both ends to allow the transfer of air as the projectile goes through the tube.

The equipment can be costly to buy and maintain along with some units being somewhat dangerous to operate. The pressure released into the tube might not make it through and be rejected at the operator when the gun is removed. Some units include pressure relief valves that prevent this danger to operators.

On Line Cleaning Systems

Cleaning systems are available for use while the system is active. This means that they help reduce the frequency of downtime. There are two on line tube cleaning types available today. One uses foam balls that circulate through the tubes in the chiller and the other includes the use of plastic brushes that are installed into each of the tubes. The idea behind the foam balls is that they should work through each and every tube in the bundle often enough that they will clean the tubes from becoming dirty. The plastic brush system features plastic baskets which are permanently attached to both sides of the chiller. Periodically the direction of the flow of water is reversed to cause the baskets and brushes to travel the length of each tube, removing debris.

With proper water treatment these systems can reduce or even eliminate the needs for tube cleaning. However these systems are costly to purchase and install. They also are not suitable for chillers that use hard water that promotes hard scaling.

Internally Enhanced Tubes

The only cleaning method for this type of chiller tube is rotary tube cleaning. These chiller tubes are making advancements with thermal efficiency and are becoming more and more common. Internally enhanced chiller tubes are those that include rifling on the inside. Rifling is when spiral groves run the length of a tube. They cause the water to circulate more evenly and provide increased surface area. Both of these elements increase the chiller’s thermal efficiency.

The rifling does mean there are areas that are below the surface of the metal. This means that many cleaning methods are simply not suited for getting into these crevices that increase efficiency. The best type of rotary tube cleaners to use in these applications are bi-directional units. This means that on the way in, and the way out, the brushes can be moving in the same direction as the spiral inside the tube. Specialized heads have also been developed to get into these grooves.

Chiller Maintenance in Arizona

If you have a chiller in or near the Phoenix valley All Kote Inc. can help you extend the life of your chiller and your cooling towers. Regular maintenance and repair keeps the system energy efficient and can save users huge amounts of energy and that means real savings on electricity bills. If you have a commercial space that uses and chiller or cooling tower make sure that you have a plan for maintenance and have All Kote help you with your chiller and cooling tower needs.

Let’s take a detailed look at what chillers do and how they operate.

Water Chiller Guide

According to Brighthub Engineering, a water chiller is a vital part of an HVAC system. It works by removing heat from the system by dehumidifying and cooling the air. The two types used in an HVAC system are the mechanical type and the absorption type.

The mechanical chiller system has a condenser, evaporator, compressor as well as other controlling devices. The absorption chiller system used an absorber and generator as opposed to a compressor. You can learn more about this process here.

How Do Chillers Work?

In most cases, a pumping system is used to circulate cool water or a glycol/water solution to the process from the chiller. Cool fluid removes the warm fluid and the heat is transferred back to the chiller. Chillers contain refrigerant, a compound that differs depending on the application but they work on the same principle we have just described. This is known as the refrigeration cycle. The refrigeration cycle commences with a low-pressure liquid/gas mix entering into the evaporator.

The heat from the process water or water/glycol solution boils the refrigerant, changing it from a low-pressure liquid to low-pressure gas. The low-pressure gas enters the compressor and then becomes high-pressure gas. The high-pressure gas enters the condenser where condenser water or ambient air removes heat to cool it to a high-pressure liquid. The high-pressure liquid moves to the expansion valve, controlling how much liquid refrigerant enters the evaporator, starting the refrigeration cycle once again.

Chillers use two kinds of condensers,  water-cooled and air-cooled. In a water-cooled condenser, water from a cooling tower cools and condenses the refrigerant. An air-cooled condenser uses ambient air to cool and condense the hot refrigerant gas back down to a liquid, ultimately rejecting the heat from the chiller to the air. You can learn more about water chillers here.

Chillers use one of two methods, an absorption refrigerant cycle or a vapor-compression for cooling fluids for the heat transfer. Each type depends on three basic principles to work.

1. Liquid gets heated and vaporized, creating a gas. As gas is cooled, it is condensed to a liquid.
2. By decreasing pressure of a liquid lowers the boiling point, while increasing the pressure raises the boiling point.
3. Heat will flow hot to cold, always.

Basic Cooling Cycle

Both absorption chillers and vapor-compression have the same basic cooling cycle’s. They use liquid refrigerant which changes stages to gas inside an evaporator that absorbs the heat from water, which then gets cooled.

Refrigerant gas gets compressed with higher amounts of pressure by a generator or compressor, then converts back to its liquid state as heat is rejected through the condenser, expanding a lower pressure combination of liquid and vapors which then ends up back in an evaporator section. This starts the cycles over.

Vapor Compressor Chiller

Consisting of four main components, a vapor compression chiller uses a vapor compression refrigeration cycle. These components include the evaporator, compressor, metering device, and condenser.

Usually, vapor compression chillers will use either CFC or HCFC refrigerants to get the refrigeration effect. The force that drives a vapor compression chiller is the compressors, which acts like a refrigerant pump.

The compressor sends compressed refrigerant gases to the condenser which then rejects any heat energy to the air outside or cooling water of the system.

The heat transfer provides the needed refrigerant gas for condensing a liquid that gets sent to the metering device.

The liquid refrigerant flow is restricted by the metering device, which results in a pressure drop. This drop causes a change in warm refrigerant liquid so that it creates a gas which absorbs heat out of the water that is then cooled because of adiabatic flash evaporation.

Metering devices are placed so expanding refrigerant gases are contained inside the evaporator, which transfers heat energy between the water that needs to be cooled and into a refrigerant gas. The warmed refrigerant gas then goes back into the compressor to begin the whole cycle over, with the recently chilled water being in a separate loop and used for the cooling process.

Absorption Chiller

A heat source is used by an absorption chiller to drive refrigeration cycles in the place of mechanical compressors. Two fluids are used for the absorption chillers, including a refrigerant that is often water, and an absorbent which is often ammonia or a lithium bromide mixture.

The absorption cycle separates and recombines these liquids, where the lower pressures allow the water to change phases easier than usual, with a high affinity of the liquids promoting easier absorption.

This cycle starts with a combination of liquid absorbent and refrigerant water which gets heated at higher pressures, boiling water from the solution. Then, the vapor from the refrigerant water gets sent to the condenser coil, heat is rejected and condensed to a high pressure liquid. This liquid then gets put through the lower pressure evaporator using the method of adiabatic flash evaporation to convert it back into a gas, which absorbs heat from the water which is to be cooled. The liquid absorbent is now concentrated in the generator, and gets recombined with a lower pressure refrigerant vapor that is returned by the evaporator, and the cycle starts over.

Phoenix Valley Chiller Maintenance

Chiller Maintenance keeps equipment in good condition, operating more efficiently, and saves money by using less energy. All Kote Lining, Inc. offers chiller maintenance and repair to the Phoenix Valley. We keep chillers and cooling towers operating at their highest possible performance. Refurbishment is one of our services which saves companies and municipalities significant operating costs in comparison to needing cooling tower or chiller replacement. Get in touch with All Kote Lining, Inc. to learn more about what we can do for your chillers and cooling towers.

Call 480-966-4446 or Contact Us

If you are searching for Chiller Types, 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.

Contents on this page:[one-half-first]

1. Types of Chillers
2. Air Chillers
3. Water Chillers
4. Evaporative Condensed Chillers
5. Chiller Subcategories
6. Reciprocating Chillers
7. Rotary Screw Chillers
8. Centrifugal Compression Chillers
9. Absorption Chillers
10. Where Are Chillers Used?

Chiller System Types

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.

• Air Chillers
• Water Chillers
• Evaporative Condensed Chillers
• Reciprocating Chillers
• Rotary Screw Chillers
• Centrifugal Chillers
• Frictionless Centrifugal Chillers
• Screw Driven Chillers
• Absorption Chillers

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.

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.

Industrial water chillers are used in a diverse range of applications where chilled liquid or water are circulated through processing equipment. Most frequently utilized to cool machinery and products, they are also used in die and tool cutting, chemicals, machine tool, lasers, semiconductors, injection molding and more. An industrial chiller works by moving heat from one place to a different location. Often a solution of glycol and water is used to transfer the heat back and forth from the chiller and that may necessitate a pumping and reservoir system. A sufficient cooling system is essential to your level of productivity.

Water Chiller Definition

According to Brighthub Engineering, a water chiller is a vital part of an HVAC system. It works by removing heat from the system by dehumidifying and cooling the air. The two types used in an HVAC system are the mechanical type and the absorption type. The mechanical chiller system has a condenser, evaporator, compressor as well as other controlling devices. The absorption chiller system used an absorber and generator as opposed to a compressor. You can learn more about this process here.

How Do Chillers Work?

In most cases, a pumping system is used to circulate cool water or a glycol/water solution to the process from the chiller. Cool fluid removes the warm fluid and the heat is transferred back to the chiller. Chillers contain refrigerant, a compound that differs depending on the application but they work on the same principle we have just described. This is known as the refrigeration cycle. The refrigeration cycle commences with a low-pressure liquid/gas mix entering into the evaporator.

The heat from the process water or water/glycol solution boils the refrigerant, changing it from a low-pressure liquid to low-pressure gas. The low-pressure gas enters the compressor and then becomes high-pressure gas. The high-pressure gas enters the condenser where condenser water or ambient air removes heat to cool it to a high-pressure liquid. The high-pressure liquid moves to the expansion valve, controlling how much liquid refrigerant enters the evaporator, starting the refrigeration cycle once again.

Chillers use two kinds of condensers,  water-cooled and air-cooled. In a water-cooled condenser, water from a cooling tower cools and condenses the refrigerant. An air-cooled condenser uses ambient air to cool and condense the hot refrigerant gas back down to a liquid, ultimately rejecting the heat from the chiller to the air. You can learn more about water chillers here.

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.

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.

Phoenix Valley Chiller Maintenance

Chiller Maintenance keeps equipment in good condition, operating more efficiently, and saves money by using less energy. All Kote Lining, Inc. offers chiller maintenance and repair to the Phoenix Valley. We keep chillers and cooling towers operating at their highest possible performance. Refurbishment is one of our services which saves companies and municipalities significant operating costs in comparison to needing cooling tower or chiller replacement. Get in touch with All Kote Lining, Inc. to learn more about what we can do for your chillers and cooling towers.

Call 480-966-4446 or Contact Us

Are you looking for “Chiller System Basics” while trying to understand how chiller systems work? If so, this post should help!

How Do Chiller Systems Work

 Overview of a Chiller System

Typically, Chillers use either an absorption refrigerant, or vapor-compression cycle to cool a fluid for the transferring of heat. Both chiller types rely on three basic principles.

• 1st – When a liquid is heated to a certain degree, the liquid vaporizes into a gas, and when that gas is gets cooled, it condenses into a liquid
• 2nd – By lowering the pressure above a liquid, the lowered pressure reduces its boiling point and increasing the pressure raises it
• 3rd – Heat consistently flows from hot to cold

Cooling Cycle Basics

The basic cooling cycle is the same for both absorption chillers, and vapor-compression. Both of these systems utilize a liquid refrigerant that changes phase to a gas within an evaporator which absorbs the heat from the water to be cooled.

The refrigerant gas is then compressed into a higher pressure by a generator or compressor, converted back into a liquid by rejecting heat through a condenser and then expanded to a low- pressure mixture of vapor and liquid and that then goes back into the evaporator section.  The cycle then starts the process all over.

Vapor Compressor Chiller

A vapor-compression chiller is made up of four primary components of the vapor-compression refrigeration cycle. These include a metering device, a condenser, a compressor, and an evaporator.

Vapor-compression chillers commonly utilize CFC or HCFC refrigerants to achieve a refrigeration effect. Compressors are the driving force behind a vapor-compression chiller, and acts as a sort of pump for the refrigerant.

Compressed refrigerant gas is sent from the compressor into a condenser unit that renounces the heat energy from the refrigerant to cooling air or water outside of the system.

The transfer of heat allows the refrigerant gas to condense into a liquid which is then sent to a metering device.

The metering device hinders the flow of liquid refrigerant which causes it to drop in pressure. Due to adiabatic flash evaporation, the drop in pressure causes the heated refrigerant liquid to change phase from liquid to gas and in doing so absorbs heat from the water to be.

The metering device is in a position so that the expanding refrigerant gas is contained within the evaporator, transmitting the heat energy from the water to be cooled into the refrigerant gas. The warm refrigerant gas is then sent back to the compressor to restart the cycle, and the newly chilled water in the separate loop can now be used for cooling.

Absorption Chiller

An absorption chiller or absorption refrigerator uses a heat source to drive the refrigeration cycle in place of a mechanical compressor. Absorption chillers use two fluids which include a refrigerant, usually water and an absorbent; commonly a lithium bromide solution or ammonia.

These liquids are then separated and recombined in the absorption cycle where, due to the low pressure conditions, the water can more easily change phase than it normally would. The high affinity of the two liquids encourages easy absorption.

The cycle starts with a mixture of liquid refrigerant water and absorbent, that is heated at a greater pressure to boil the water out of solution. After that, the refrigerant water vapor is sent past a condenser coil where heat is lowered and is condensed into a high pressure liquid. The liquid refrigerant water is then sent to the lower pressure evaporator where through adiabatic flash evaporation returns into a gas, absorbing the heat from the water to be chilled. The condensed liquid absorbent from the generator is sent back to be recombined with the low-pressure refrigerant vapors returning from the evaporator restarting the cycle over again.

Cooling Towers

The heat energy absorbed by the chiller is required to be rejected out of the system and into the atmosphere. Evaporative heat rejection devices called cooling towers are commonly used to lower the water temperature in larger chiller installations.

Phoenix Chiller Maintenance & Repair

If you have a industrial or commercial building that uses chillers All Kote Lining, Inc. can help maintain and repair your chiller.  Regular chiller maintenance, chiller tube coating, and other quality services help chillers be more efficient, use less energy, and ultimately last longer. Give us a call to find out what we can do for you and your chillers in the Phoenix Valley.

Call Today – 480-966-4446

Absorption chillers all work on a similar principle, when the pressure system is low the absorption fluid evaporates and the heat is removed from the water parts that are chilled and the absorption solution is then regenerated either by steam, hot water, or exhaust gas.

Outline:

If it is in a waste energy plant or cogent, it will usually consist of stream fired absorption due to the cost of the steam being lower. If it is in a hybrid and/or higher cost of electricity areas it usually will use the direct fired, using natural gas units. Many users will buy absorption chillers to use as an environmental advantage since absorption chillers do not use refrigerant such as CFC and/or HCFC.

Principle & Mechanism:

As a principle, it does not sound presumptuous to use a burning flame in order to cool something down, however,that is just what is done with absorption chillers. The refrigerant is merely water that acts as a medium and it goes through a phase which causes a mechanism to change causing a cooling affect. It then takes a second fluid to make the process work and that is salt (usually in the form of lithium bromide). Next, the two fluids are then separated by the use of heat, and when the two are put back together and the water remixes with the salt at a slow pace, normally at a low temperature having a normal atmosphere pressure, which will cause water to vaporize at 212F within an absorber, the vaporizing water is cold enough to put off water as cold as 46F.

An explanation on description of structure, shapes, and/or diagram of system:

One could use electric chillers, however, they do cost a lot more to use, and if purchasing right out, they are going to be about twice as much. So, if one wanted to justify an absorption system that is base-loaded, it is going to take more than a reason like average electric costs. That is why the economy favors the hybrid systems, they have a combination that lets them use absorption chillers when the electricity is at its peak, however, it also lets it use electric chillers when it is not at its peak, or rather, during its base load of operation.

The savings effect on energy:

The energy savings is estimated to be upwards toward 50% more efficient as the conventional chillers.

The equipment cost, economically speaking:

The cost of the equipment that is chosen will depend on several different factors, which include: equipment, utility rate, equipment building type, climate, and scalar ratio.

Remarks:

Absorbers have a co-efficient in its performance (COP) that factors in at near 1.0, when compared to the engine driven compressors, which factor in at nearly 1.5 and the electric one at nearly 3.0.

How does an absorption chiller work?

There are various stages that coolant goes through during the cycle of a absorption chiller. Read more below to understand individual principles.

The effect of the single lift hot water driven absorption chillers:

Hot water driven for a single lift absorption chiller means that the water is chilled one time using a refrigerant in a double tray inside the evaporator. The refrigerant vaporizes and is absorbed, turning into a concentrated solution, usually, potassium bromide, a concentrated solution coming out of the generator. While this concentrated solution is being diluted it is absorbing the refrigerant (which is evaporated) and heat is being absorbed by the cooling water. Now, the absorber, with the diluted solution goes into the generator by heat exchanging. The water is at 95⁰C and is heating up the diluted solution, causing the refrigerant to vaporize. After the refrigerant has vaporized it becomes condensed, returning to the refrigerant circuitry. It has regenerated the diluted absorbent and can recycle it.

The double driven hot water effect:

In an absorption chiller for a hot water driven with a double lift there is a primary cycle and the auxiliary cycle. Whereas, the chilled water is cooled down two times by the refrigerant of the double tray located in the evaporator, Once the refrigerant has vaporized it is turned into concentrated solution, which comes out of the second generator. The double tray system increases the amount of vapor that the absorber can absorb by the cooling water. Then the diluted solution that is in the absorber will flow into the first generator by the use of a lower temperature heat ex changer and a higher temperature ex changer, at 95⁰C hot water will heat the diluted solution, and then it vaporizes the refrigerant. While the absorbent solution is an intermediate solution at the first generator, and it flows into the second generator through high-temperature heat ex changer. Now the intermediate solution that is in the second generator is being heated with use of the hot water, making more refrigerant vaporize in the second generator as well. Auxiliary diluted solution is being made as the vapor is being absorbed by the absorbent solution, which is already in the auxiliary absorber. Next, the auxiliary heat ex-changer uses the auxiliary generator to carry the auxiliary diluted solution, which is heated by use of the hot water that comes from the first generator, turning it into an auxiliary concentrated solution. In short, first the auxiliary concentrated solution gets carried to the auxiliary absorber by way of the auxiliary heat ex-changer. All vapors that are generated in the first generator, and also the auxiliary generator become condensed within the condenser, letting it flow to the evaporator. The cooling water then absorbs the condensers heat.

Direct-fired Absorption Chiller:

The direct-fired system is very similar to the hot water single lift series with one exception, and that is that it does not use hot water in order to generate an absorption solution, instead, the solution is regenerated by using a gas flame and heating it directly, this also regenerates the refrigerant.

Driven absorption chiller using the double effect of exhaust gas:

The water in the evaporator boils at a low temperature of 4.4⁰C, this is due to the vacuum conditions inside the evaporator. The chilled water gets cooled down from the tubes of the evaporator by use of latent heat. Which in return lowers the temperature of the outlet to near 7⁰C. The transfer of the heat gets help from the spraying of refrigerant or rather distilled water, through a refrigerant pump. Then the refrigerant or water vapors will flow to the absorber and the lithium bromide solution absorbs it. The lithium bromide now becomes a diluted solution as it reduces its amount of absorption.

The diluted solution now gets transferred by a solution pump to a generator and it is re-concentrated (re-concentrating takes two stages, which is the double-effect) by boiling the previous water absorbed, off. With the diluted solution then being pumped into a higher temperature generator and heat in order to re-concentrate into a medium concentration solution using exhaust heat coming out of the reciprocating engine’s exhaust gases.

Flowing from the high temperature generator is the intermediate solution and going into the lower temperature generator and it is heated, becoming a concentrate solution through high temperature water vapors being released out of the solution during the time in the high temperature generator.

Because of the low-temperature generator acting like a condenser in the high temperature generator, the applied heat energy of the high-temperature generator is being used in the low temperature generator as well. Compared to the single stage chiller it reduces the input by around 45%. The vapors that are released on the shell side in the low temperature generator goes into the condenser and cools, now it returns into a liquid form. The refrigerant (water) now goes back to the evaporator to begin another cycle.

The tubes of the absorber first get cooling water from the cooling tower to cool the chiller, and then circulate, removing heat caused from the vaporization.

Phoenix Chiller Repair & Maintenance

If you need to have chiller repair done on your chiller in the Phoenix area All Kote Lining, Inc. is here to help. We understand how to inspect, recondition, repair, and perform general maintenance on your chillers. This will get you the longest life, best efficiency, and get you the peace of mind you need when it comes to the chiller installed in your building or business. If you have questions or would like to schedule your chiller repair please call 480-966-4446.