types of water-cooled chiller units
water-cooled chillers is very mature and there is no single standard. It is mainly divided according to different dimensions such as compressor type, application temperature, and structural form .
To give you a clear understanding of this category, I've broken it down into the following main classification dimensions:
I. Classification by compressor type (the most fundamental classification method)
This is the most crucial standard for distinguishing equipment performance and applicable scenarios.
type | Features | Typical cooling capacity range | Applicable Scenarios |
Screw chiller unit | It has a simple structure, low failure rate, and long service life; it can be steplessly adjusted within the range of 10% to 100%, and has high efficiency under partial load. | 121 kW ~ 3489 kW | Medium to large-sized commercial buildings and industrial cooling are the mainstream models in the current market. For example, Hitachi's WZ series and WZP series belong to this category - 1 . |
Centrifugal chiller unit | It has a large single-unit capacity, high efficiency, and stable operation. However, it has high requirements for design and manufacturing processes, and may experience "surging" under low load. | 1055 kW ~ 35160 kW | Projects with huge cooling capacity requirements, such as super-large buildings (such as large shopping malls, airports, and data centers) and district cooling systems. |
Scroll chiller unit | It operates quietly and smoothly, and has a compact size. The compressor itself has a low failure rate, but due to structural limitations, the single-unit capacity is relatively small. | Small to medium cooling capacity range | Small commercial buildings, high-end residences, precision machine rooms, and other occasions with requirements for noise and space. |
Piston chiller | It has mature technology, uses simple materials, and is relatively inexpensive. However, it has many parts, many wear parts, and high maintenance costs, and is gradually being replaced by scroll and screw types. | 58 kW ~ 1163 kW | Small air conditioning systems or some specific industrial processes use cooling, but their applications are decreasing. |
II. Classification by chilled water outlet temperature (distinguishing between air conditioning and process water)
This classification determines whether the equipment is used for conventional comfort air conditioning or for industrial production.
Standard type (air conditioning type) : The outlet water temperature is usually above 0℃, and the common design temperatures are 7℃, 10℃, 13℃, 15℃, etc. It is used for cooling in central air conditioning systems.
Low-temperature type: The outlet water temperature can be between -5℃ and -30℃. These units usually employ special designs (such as using low-temperature refrigerants like R404A) to meet the requirements of industrial-grade low-temperature processes.
III. Classification by structural form and sealing method (related to installation and maintenance)
• By unit structure :
Open (stand-up) : The compressor, condenser and other components are installed openly on a steel base, usually placed in the machine room for easy maintenance.
Enclosed type (sealed): All components are integrated into one enclosure, resulting in a compact structure, easy installation, and a more aesthetically pleasing appearance.
• According to the sealing method: it can be divided into open type, semi-closed type and fully closed type . The main difference lies in the connection and sealing method of the compressor and motor, which affects the maintenance difficulty and sealing performance.
IV. Classification by refrigerant and special purpose (adapted to special processes)
Standard water-cooled chiller units use water as the refrigerant, but when the process requires temperatures below 0°C, the refrigerant must be changed.
• Brine chiller: Uses brine solution as a refrigerant for process cooling at lower temperatures.
• Ethylene glycol chiller: Uses an aqueous solution of ethylene glycol to prevent freezing at low temperatures.
