Industrial chillers take the principles behind a home air conditioning system and take it to the next level. These coolers do more than create chilled fluid They can also cool air or a refrigerant. While some industrial chillers are used for air conditioning, others have more specific applications based on the companies using them.
What is a water chiller?
A chiller is a machine that removes heat from a liquid via a vapour-compression or absorption refrigeration cycle. This liquid can then be circulated through a heat exchanger to cool equipment, or another process stream (such as air or process water). As a necessary by product, refrigeration creates waste heat that must be exhausted to ambient or, for greater efficiency, recovered for heating purposes. Chilled water is used to cool and dehumidify air in mid to large-size commercial, industrial, and institutional facilities. Water chillers can be water-cooled, air-cooled, or evaporative cooled. Water-cooled systems can provide efficiency and environmental impact advantages over air-cooled systems. Industrial water chillers are used in a variety of applications. Suppliers of air treatment solutions to the industrial and commercial sectors include the sale of industrial water chillers with their compressors eliminating impure and unwanted condensate from the compressed air system. Industrial water chillers are the perfect solution for hot humid and dusty environments. Industrial water chillers are in place to maximize your control on your chilled water supply. They combine advanced design features that include energy saving scroll compressors and sophisticated microprocessors. Productivity increases and your industrial applications are optimized delivering you a reduction in costs.
How does a Chiller Work?
In most process cooling applications, a pumping system circulates cool water or a water/glycol solution from the chiller to the process. This cool fluid removes heat from the process and the warm fluid returns to the chiller. The process water is the means by which heat transfers from the process to the chiller.
Process chillers contain a chemical compound, called a refrigerant. There are many types of refrigerant and applications depending on the temperatures required but they all work on the basic principle of compression and phase-change of the refrigerant from a liquid to a gas and back to a liquid. This process of heating and cooling the refrigerant and changing it from a gas to a liquid and back again is the refrigeration cycle.
The refrigeration cycle starts with a low-pressure liquid/gas mix entering the evaporator. In the evaporator, heat from the process water or water/glycol solution boils the refrigerant, which changes it from a low-pressure liquid to a low-pressure gas. The low-pressure gas enters the compressor where it is compressed to high-pressure gas. The high-pressure gas enters the condenser where ambient air or condenser water removes heat to cool it to a high-pressure liquid. The high-pressure liquid travels to the expansion valve, which controls how much liquid refrigerant enters the evaporator, thereby beginning the refrigeration cycle again.
There are two types of condensers used in chillers; air-cooled and water-cooled. An air-cooled condenser uses ambient air to cool and condense the hot refrigerant gas back down to a liquid. It can be located inside the chiller or can be remotely located outside, but ultimately it rejects the heat from the chiller to the air. In a water-cooled condenser, water from a cooling tower cools and condenses the refrigerant.
Applications of Industrial Chiller
The applications for industrial chillers have a wide range. Pharmaceuticals, food production, petrochemicals, plastic production, metal plating and agriculture are some of the industries that benefit from having industrial chillers for their many manufacturing processes. They may employ them for:
- Cover Area Cooling: Manufacturing equipment generates a lot of heat. Such a hot environment can be dangerous for employees. A cover area cooling unit can cool the air in a factory, making it safer and more comfortable for the workers. These air-cooling systems also are used for keeping offices and other working spaces cool during warm weather. Rental package units can cool temporary areas without the cost or effort of purchasing and installing a full-sized HVAC system.
- Process Cooling: Industrial processes create heat through friction, equipment or burning. To increase the longevity of the equipment and keep the process running smoothly, you need a process chiller. Unlike standard HVAC systems you have in your home or office, process chillers cool a liquid that circulates the area to be cooled, maintaining a set temperature. This liquid may be water, propylene or ethylene glycol, or even something like methanol or ethanol. Since processes are as diverse as petrochemical manufacturing and plastics production, process coolers have many different forms. The cooled liquid circulates equipment to keep it at safe operating temperatures or cool it to a lower temperature for a process.
- Plastic Manufacturing: Plastic is very temperature sensitive. If it gets too hot, plastic can melt. During production, plastics need to cool in molds to an appropriate temperature. Cooling the molds requires a hard-working chiller. For extruded plastics, the formed plastic needs a cooling bath to chill in. A chiller provides the cooling for this bath. For extrusion plastics production, the ideal setup includes a second heat-exchanger to separate the water used for cooling the equipment and the extrusion water. Keeping these waters separated prevents contamination from plastics in the extrusion water.
- Metal Plating and Anodizing:Metal plating can be done with electroplating or electroless plating. Both methods require high temperatures. Anodizing is a similar process to reduce corrosion on non-iron surfaces. It, too, uses high temperatures to electrically bond the finish to the metal. Because both anodizing and metal plating require temperatures ranging in the hundreds of degrees, companies specializing in these processes need a heavy-duty chiller to remove the heat produced from the solution. Some shops solve the problem of heat removal by sending the plating or anodizing liquid to a heat exchanger while others will use glycol or water-containing coils to cool the fluid in the tank.
- Food Processing: The food production industry is the first application many people think of when they list uses for industrial chillers. While most people think of refrigerators, industrial process chillers are also an essential part of this industry. Glycol coolers send chilled propylene glycol through cooling coils for chilling food or beverage storage units. For instance, breweries and wineries frequently use glycol chillers for keeping their products at the perfect temperature. The beverage industry isn’t the only one to use chillers. Food manufacturers use process coolers to chill dough mixers or cool ice cream makers.
Advantages And Disadvantages of Water-Cooled Chillers
Water-cooled chillers usually don’t need replacement as often as air-cooled chillers do. They aren’t exposed to outdoor elements such as rain, snow, ice, and heat, which makes them less vulnerable.
While air-cooled chillers have ducts and vents that create noise, water-cooled chillers operate quietly. The flow of water through the system doesn’t result in the same noisy expansion and contraction that’s heard in air-cooled chillers. Quiet operation is particularly important in environments such as hospitals and schools, where noise can cause disturbance to occupants.
The film coefficient is 10 to 100 times better in water-cooled chillers versus air-cooled chillers. This means that water-cooled chillers transfer heat more efficiently. The result to businesses is a savings on energy costs.
No Open Space Needed
Air-cooled chillers need to stay outdoors in an open space with plenty of fresh air to operate. Water-cooled chillers stay inside buildings, which makes them ideal for companies that don’t have access to enough outdoor space.
Water-cooled chillers use water as a refrigerant instead of toxic chemicals. This makes them safer for people who have contact with them.
Air-cooled chillers are cheaper than water-cooled chillers because they don’t require parts like cooling towers and condenser water pumps. Many companies feel that the longer lifespan and savings on energy costs make water-cooled chillers worth the initial high investment, however.
Since water-cooled chillers have more parts, they require more maintenance. Companies should prepare to pay for periodic inspections, water treatments to remove impurities, and regular cleaning of the chiller’s machinery. More maintenance also means more downtime for the chiller. The more parts a machine has, the more things there are that can go wrong with the machine, which means water-cooled chillers are more likely to require repairs than air-cooled chillers.
The extra parts in water-cooled chillers also make installation more of a hassle. This can mean higher labor costs for installation of water-cooled chillers as opposed to air-cooled chillers.
Requires Mechanical Room
Businesses need to have a mechanical room to house a water-cooled chiller. This is to ensure that the chiller will function properly with its cooling tower and extra components.
Not Ideal For Drought-Stricken Areas
Since they use a good amount of water, water-cooled chillers aren’t great in regions that have water shortages. Companies that pay water costs can expect these bills to rise with the use of a water-cooled chiller. Some drought-stricken areas also have restrictions on water-cooled chiller use.
Less Efficient in Humidity
Although water-cooled chillers are overall more efficient than air-cooled chillers, they’ll operate less efficiently in humid environments. This is because humidity raises the wet-bulb temperature, which indicates how efficiently water absorbs heat. Water-cooled chillers in humid environments may also make building occupants feel cold and clammy.