What is a Chiller?
A chiller is a technology that cools by moving refrigerant through components that extract heat from the refrigerant and reject it.
An industrial chiller is typically comprised of a compressor, condenser, expansion valve and evaporator which all work together to circulate the refrigerant to allow for effective removal of heat from processes, operations or environments.
There are various types of industrial chillers because of the methods used to remove heat from the product being cooled. The most noticeable difference is if the chiller uses air or water as its cooling medium.
For example, some industrial chillers are referred to as air-cooled because a fan moves air over the heat exchanger to remove heat. Or, a water-cooled chiller uses a cooling tower to circulate water to remove heat.
Aside from method of cooling, industrial chillers are categorized by the type of compressor used.
While all compressors compress the refrigerant to increase its temperature and pressure before it enters the condenser, they do so utilizing various configurations and methods of operation.
industrial chillers utilize vapor compression or absorption technology. They are designed to produce a flow of freshwater, and keep this freshwater at a designated temperature.
This temperature controlled water is produced by constantly circulating fluid to cool things down by removing heat.
Key takeaways
- An industrial chiller is technology that produce fluid that can make things cold through heat extraction from the fluid.
- In the closing years of the twentieth century, new developments gave rise to chilling equipment that could produce temperatures for cooling applications in a number of industries.
- Industrial chillers are divided according to the means of rejecting heat from the refrigerant and the refrigerant compressor type. Some chillers are designed especially for applications that perform unique and unusual functions.
- Even with a great number of industrial chillers available, most of them work on the same principle of removing heat.
- Most of the industrial chillers operate the same way when it comes to the basic operation, but as with most types of industrial equipment, preventative maintenance provides assurance that they will continue to operate within their specifications.
How Do Industrial Chillers Work?
Despite the number of industrial chillers made available to us, they all operate on the same principle when it comes to taking heat away.
The key to this process is the coolant or refrigerant that can absorb more heat than air, and helps stabilize temperatures. The idea of an industrial chiller is that cooling is accomplished by extracting heat from a process and dispersing it to the atmosphere.
All industrial chillers consist of a condenser, compressor, an expansion valve, and an evaporator that transports a fluid or refrigerant. The operation of an industrial chiller is to change the refrigerant from a liquid to a vapor and back to a liquid.
The refrigerant absorbs heat from the process in vapor form. The refrigerant is recirculated throughout the system to absorb and discharge heat away from the process or operation, as the refrigerant is both being compressed and condensed back to a liquid.
Refrigeration
Circuit Compressor: The compressor receives refrigerant at low pressure and temperature and compresses it into high-pressure, high-temperature gas. There are several types of compressors; the centrifugal, turbocor, and screw compressors are likely to be the most common.
Condenser: The compressed gas is passed through coils in the condenser. Air or water flows across the coils, allowing for heat removal and therefore dissipating heat from the refrigerant. As the refrigerant loses heat and is cooled, it condenses back to a liquid.
Evaporator: In the evaporator, the refrigerant goes back to a gas, becomes extremely cold, and absorbs heat. This is where the refrigerant exchanges heat with the fluid, removing heat from the fluid and imparting or transferring it to the refrigerant. The different types of evaporators are: copper coil, shell and tube, and plate.
Expansion valve: The expansion valve, also called a thermostatic expansion valve or electronic expansion valve, regulates the refrigerant flow between the condenser and evaporator and adjusts the flow based on the cooling load.
Fluid Circuit
The fluid circuit (or cycle) takes the processed fluid to the item that it is cooling, which lowers the temperature of the item directly.
Pump: The pump system takes cooled water or a water/glycol solution from the industrial chiller and circulates it to the cooling system.
Filter: The filter catches contaminants, dirt, and particles in the chiller fluid (also part of the air intake system).
External Heat Exchanger: External heat exchangers are used for chillers to transfer heat to or from materials that cannot be in direct contact with the industrial chiller. The external heat exchangers can be submersible cooling coils, plate heat exchangers, shell and tube heat exchangers, or jacketed tanks.
Heat Exchanger: While the condenser is a heat exchanger, some systems utilize a secondary heat exchanger incorporated in the fluid cycle (depending on the system).
Industrial Chiller Energy Efficiency & IPLV
Chillers utilize large amounts of electrical energy during the chilling cycle and are have an efficiency rating based on the energy consumed compared to the refrigeration produced.
There are two accepted ways of measuring the efficiency of chillers – Coefficient of Performance (COP) and Energy Efficiency Ratio (EER). A high COP is noted when the system is efficiently utilizing energy, likewise with EER.
The EER and COP stated by many companies as “100% EER” or “100% COP” is not reality, as EER and COP do not reflect the load on the chiller.
The Integrated Part Load Value (IPLV) is a better reflection of a chiller’s efficiency as defined by the Air Conditioning, Heating and Refrigeration Institute (AHRI) as chillers do not typically work at 100% load either. The IPLV includes a calculation as chillers typically do not work at their design capacity.
The IPLV reflects the fact that the majority of units operate below their design capacity the majority of the time. The IPLV is a better measure of the efficiency of a chiller, since it measures efficiency at four different load levels.
It makes sense to use the IPLV to measure efficiency because chillers represent one of the highest electricity consuming areas for commercial businesses, so it is wise for buyers to know how to measure efficiency in chillers.
A well-functioning chiller has low operating costs which means significant cost savings for the organization.
Types of Industrial Chillers
Industrial Chillers can be grouped into types based on how the refrigerant disperses the heat it has absorbed and the type of compressor being used. There are also Chillers that are uniquely designed for specialized and particular purposes.
In addition to these categories, technological advancements are occurring continuously, which changes the designs of Chillers, so an exhaustive list of industrial chiller types is not possible.
Water Cooled Industrial Chillers
Water cooled industrial chillers tend to be used in conjunction with a cooling tower and a condenser water treatment system in order to rid the water of mineral deposits. water with a low temperature flows in the chiller from the water cooling tower, the water is chilled and then flows out of the chiller.
Air Cooled Industrial Chillers
An air cooled industrial chiller will be utilized where the heat rejection is not a problem, because the chiller absorbs heat from the circulated water and causes heat rejection into the air.
First the evaporator absorbs the heat energy from the chilled water, and then the chiller’s condenser releases some of the heat as the refrigerant vapor condenses into a liquid.
Screw Industrial Chillers
Screw industrial chillers, like water cooled and air cooled types, can utilize a helical rotor to move refrigerant vapors and compress refrigerant vapors while the chiller is operating.
Scroll Chillers
Screw Industrial Chillers with both air and water cooled types are defined as industrial chillers which have a helical rotor. These screw chillers compress and circulate the vaporized refrigerant.
Centrifugal Industrial Chillers
Centrifugal Industrial Chillers pressurize gaseous funding refrigerants; by utilizing using compression the machines use tries to reorder kinetic energy into static energy of the refrigerant, heating and pressuring it. The impellers takes in the gaseous refrigerants and compresses it.
Absorption Chillers
In an absorption Industrial chiller, a generator with steam or hot water creates the gaseous refrigerant. The vapor will go to the condenser and back into the Absorber. The vapor gets absorbed into a solution and then coheres out the heat.
Reciprocating Industrial Chillers
Reciprocating Industrial Chillers utilize pistons with a chamber that generates the pressure of refrigerant. They can be either open or sealed, with sealed being both all of the components housed inside a housing. Because reciprocating chillers act very similar to car engines, they require routine maintenance.
Explosion-Proof Industrial Chillers
Explosion proof industrial chillers are meant for heavy-duty industrial chiller applications with specific requirements at the NFPA level in construction.
These units have specially enriched structural movements against flammable materials, which is a permanent cost when ordering. These chillers are ordered to serve worker protection and safety, but have the same chiller field as a standard chiller with more enriched coverage protection.
Low Temperature Industrial Chillers
Low Temperature Industrial Chillers are Common for Industries in below freezing that require chillers capable of reaching temperatures at -40 degrees Fahrenheit (-40 degrees Celsius).
They are used for ice rinks, petrochemical cooling, chemical extraction, and medical, pharmaceutical, and food processing industries as well as product testing labs.
Evaporative Industrial Chillers
An evaporative industrial chiller uses evaporation to cool air. As water evaporates, it turns to gas and takes away high-energy particles resulting in a large drop in the temperature of the air about it.
We can experience this cooling effect when mist is introduced into a room. An evaporative chiller extends this natural evaporation process with technology to optimize the cool air produced.
Evaporative industrial chillers consists of a water reservoir, a fan, and thick pads. The fan pulls in hot air which passes through the pads that are absorbing water from the reservoir.
As the hot air passes through the wet pads, the water on the surface evaporates caused nearly a 20 degree Fahrenheit drop in temperature.
Thermoelectric Industrial Chillers (TEC)
Thermoelectric coolers (TECs) works on the Peltier effect. The Peltier effect is described as a heat flux across the junction of two different things when a DC current is applied.
In this case, they have arranged the positive and negative semiconductors parallel in the thermal path and in series along the electrical path.
When voltage is applied, the electrical power causes electrons to carry heat going to one side of the electron and causing the other side to be cooled. The heat is absorbed by a heat sink and blown into the ambient air by fans.
A TEC assembly could be mounted directly to a cold plate, or used to cool a liquid refrigerant. TECs (thermoelectric coolers) are essentially used in applications with less than 400 watts of cooling.
Uses of Industrial Chillers
Industrial chillers rely on the physics of either vapor compression or absorption and are designed to provide a defined temperature of coolant into a system, while providing continuously flowing coolant.
This is accomplished with a fluid that is constantly moving and cooled to provide lower temperatures by removing heat.
With technology advances since the 1950s, into the 21st century, we now have cooling and heat removal equipment capable of providing temperatures suitable for processes such as laser cutting and die casting.
Most of what was developed in the mid-20th century as simple water baths, is now an essential component of today’s industry.
Industrial
Industrial processes generate heat through friction, high-powered machinery, and the use of a furnace or oven. To increase the lifespan of heavy-duty machinery and allow equipment to run efficiently and at full productivity, an industrial chiller can provide cooled liquid to your equipment or process.
Work Environment
On the manufacturing floor temperatures can quickly rise as equipment is being run at a full operation, creating an unsuitable working environment.
In multi-shift production, employers want to protect their employees and utilize industrial chillers to maintain suitable working conditions.
With the addition of an air handling unit, industrial chillers can maintain a work area by cooling a work area with chilled air, similar to an air-conditioning unit. Depending on the building, air conditioning chillers may be located above or inside of the building.
Plastic Manufacturing
Plastic has a degree of sensitivity to temperature and can be negatively affected if temperatures are too hot; therefore proper cooling is paramount. The temperature of the cool down on a mold will impact the quality of the finished product.
Industrial chillers provide a cooling bath which aids in the quality of the plastic molded product from the cooling stage in the product cycle.
An extruder provides a heat exchanger which utilizes cooling water to separate the cooling water from the extrusion process which is managed by temperature control.
Metal Plating
In the metal plating process, the high temperature from high-temperature electroplating or even electroless processes, is how metal is plated with heat. Heavy duty industrial chillers will supply cooling to absorb the heat from the plated metal.
Food Production
The food industry consists of strict storage temperature regulations on the storage of food ingredients and finished products.
Industrial chillers operate the same as a traditional cooling mechanism, maintaining the required temperature for the product during the storage phase.
Power Generation
Power plants create a large amount of thermal energy through the processes of generating electricity.
Chillers are utilized to assist in absorbing the release of heat from the significant amounts of components, processes, etc to continue the generating of effective cooling mechanisms.
Medical Industry
Medical devices and applications need to successfully compress and regulate temperature. Maintaining control of the heat given off of medical devices such as MRI scanners, CT scanners, LINAC machines, is important. Industrial chillers provide a steady supply of cooling for these medical needs.
Pharmaceutical
The production of medicines requires chilled water and the production of medicines requires temperature control, just like the industrial chillers provide for.
Industrial chillers are used to control the level of precision and accuracy for these chilling applications, and they may be either central or compact process chillers.
The primary types of pharmaceutical industrial chillers include reciprocating, screw driven, centrifugal, and absorption.
Laser
Laser industrial chillers are primarily designed to chill laser applications or laser equipment. In order for the laser to generate maximum efficiency, it must hold the highest level of operational wavelength.
CO2, high power exciters, and ion lasers must be precise. They rely on a tightly controlled industrial chillers water cooling system to maintain it.
Temporary Chiller Systems
An estimated two-thirds of new construction sites utilize rented temporary HVAC systems for heating, ventilation, and cooling. Temporary HVAC systems are installed, operated, and maintained to suit the timeline and budget of the project.
Builders and contractors at temporary construction sites appreciate the opportunity, flexibility, and efficiency of temporary HVAC systems to obtain contracts for work and for running their project timelines effectively.
The primary uses of temporary HVAC systems are almost always limited to three uses:
- Heating and Dehumidification: new construction during cold weather, replacement of equipment or a failed heating system, and applications requiring humidity control (i.e., data centers).
- Ventilation: maintaining negative pressure or circulating air in smoke-filled areas, positively pressuring large vessels, and cooling submarines.
- Air Conditioning: for projects being worked on during the summer, replacing the current system, or when the chiller plant has failed.
The portable industrial chiller shown below is an example of a temporary unit for use at a project site. This design is available as both air-cooled and water-cooled. The chiller is designed with features to provide exceptional performance.
How Are Industrial Chillers Maintained?
Industrial chillers perform almost identical operations; however, they do require maintenance when appropriate. Scheduled maintenance is essential to unlocking the chiller’s peak performance.
Industrial chillers are considered industrial equipment, and anything considered equipment should be monitored and inspected.
Manufacturers recommend following the best practices for maintaining and checking the components of a chiller to promote that they operate as intended.
Maintenance for Condensers
Heat transfer is a major aspect of the operating chiller. Condensers coils can slow down the heat transfer process simply by having debris or dust accumulate, as it can also inhibit unrestricted air flow.
Refrigerants
For optimal performance of an industrial chiller, it’s also with the refrigerants. An improperly charged refrigerant can have an adverse affect on the efficiency and operating capability of the chiller.
Water
Water must also be handled in a manner that it meets the required flow compatibility for cooling towers. Water can slow down flow from debris, dirt, solids and contaminants, adversely affecting the performance of the chiller.
Conduct Reservoir Checks
To achieve optimal performance from a chiller, all reservoirs should be routinely checked confirming there are adequate levels of fluids.
Temperature Check
Chillers do most desired performance in the range of 50 °F (10 °C) but need to be monitored so any sudden change of temperature would not go unnoticed as it could negatively impact the operations running on the chiller.
It’s a good practice to routinely check the glycol inlet-on type- as well as the outlet mixer temperatures to catch potential problems before they happen.
Cleanliness
All equipment needs cleaning, especially the parts which may be exposed to dirt and dust in the manufacturing of the chiller.
Keeping the chiller parts clean will maintain the highest level of efficiency. Regularly replacing any type of filter that can become clogged will also contribute to maintaining peak efficiency.