How to Select the Right Water Chiller
Water chiller systems see use across a wide variety of industries. These systems supply chilled water to cool products, mechanisms, and machinery throughout a facility. Water chillers are typically closed-loop systems, which means that water is constantly circulating to be repurposed for maximum efficiency.
Water chiller systems are known for providing a high level of energy efficiency. They see heavy use in the food and beverage, chemical, medical, and pharmaceutical industries, among others. Depending on the intended application, there are three options: scroll chillers, screw chillers, and centrifugal chillers. The largest differentiator between these types is their load capacity.
Scroll Chillers: Optimum Energy Efficiency
Scroll chillers are oftentimes the most economical choice between the three types of water chillers. They are typically the best choice for organizations who deal with low-capacity projects. This is because capacity control is stepped rather than modulated, which may be disadvantageous in applications that involve a high capacity.
Scroll chillers are so named because they utilize scroll compressors. These compressors trap and then compress refrigerant vapor, increasing system pressure as the volume of the vapor is reduced.
Key features of scroll chillers include:
- Greater operational reliability
- Low noise emissions
- More difficult to manage capacity control
- Individual refrigeration circuits for each compressor
- Electronic expansion valves
The major advantage offered by screw chillers comes from their ability to engage in modulated capacity control. While scroll chillers utilize stepped capacity control based on the number of compressors in a system, screw chillers use only one compressor. This means that the output capacity of that one compressor can be set anywhere within the range of 20-100%.
Screw chillers utilize screw compressors. These compressors are available in sizes nearing 500 tons; but large screw chillers are ideal for applications where capacity exceeds 200 tons.
The features of screw chillers include:
- Cool efficiently according to building capacity
- High level of energy efficiency
- Moderate levels of noise emission (greater than scroll chillers)
- Minimal maintenance requirements
- Long durability horizon
- Small footprint
Centrifugal chillers rely on centrifugal compressors, using the principle of dynamic compression to both compress and raise the pressure of a refrigerant. A rotating impeller accelerates the refrigerant and converts velocity energy into pressure energy.
Centrifugal chillers are the best chillers for organizations that need to cool a large amount of space. Their capacities range from 200 tons to thousands of tons depending on how many centrifugal compressors are inside of the chiller itself. These chillers offer users the most extensive form of modulated control of all three chiller varieties. Capacity may be configured by changing any of the following:
- Number of stages
- Compressor speeds and sizes
- Impeller diameters
- Refrigerant types
The defining features of a centrifugal chiller include:
- Very reliable
- Highly efficient
- Compact when operating range is taken into consideration
- Very high noise emissions
- Ideal for cooling larger facilities
Compressed Air Systems supplies several nano process chillers capable of improving the efficiency of your company’s cooling applications. The distinctive closed circuit design of nano products provides users with greater control over water temperature than traditional systems and reduces system waste levels.
Download our eBook, “Water Chiller Selection Guide,” for more on the three types of chillers, a view of typical configurations, and a bonus application worksheet for industrial process chillers to help you decide which chiller solution is right for your operation.