What Are The Three Types Of Chillers?

A chiller is a device that achieves refrigeration through steam compression or absorption cycle. It is widely used in air conditioning, industrial cooling and other fields. Its three common types and characteristics are as follows:
1. Piston chiller
Working principle
The refrigerant gas is compressed by the reciprocating motion of the piston in the cylinder, and the refrigeration cycle is realized through heat dissipation of the condenser, throttling of the expansion valve, and heat absorption of the evaporator.
Features
Advantages:
Mature technology, simple structure, easy maintenance, and low initial investment cost.
It has strong adaptability to load changes, and the cooling capacity can be adjusted by adjusting the number of running compressors or the number of cylinders.
Disadvantages:
The single unit capacity is small (usually below 500kW), and the vibration and noise are large.
The efficiency is relatively low and the energy consumption is high, which is suitable for small and medium-sized systems.
Application scenarios
Air-conditioning systems of small and medium-sized commercial buildings (such as office buildings and shopping malls), or small cooling equipment in industrial production.
2. Screw chiller
Working principle
The refrigerant gas is compressed by the rotation of a pair of intermeshing screws (male screw and female screw) to complete the refrigeration cycle.
Features
Advantages:
The unit capacity is large (usually 100~2000kW), the structure is compact, and the footprint is small.
Smooth operation, low vibration and noise, and long maintenance cycle (such as bearing life can reach more than 40,000 hours).
The cooling capacity can be adjusted steplessly (the adjustment range is usually 10%~100%), and the efficiency is high under partial load.
Disadvantages:
The processing accuracy is high, and the initial investment is higher than that of the piston unit.
If the gap between the screws is not handled properly, it may affect the efficiency.
Application scenarios
Large commercial buildings (such as hotels and hospitals), industrial cooling (such as chemical and pharmaceutical industries) and regional cooling systems.
3. Centrifugal chillers
Working principle
The high-speed rotating impeller is used to work on the refrigerant gas to increase its pressure and speed, and then the kinetic energy is converted into pressure energy through the diffuser to realize the compression process.
Features
Advantages:
The unit capacity is large (up to several megawatts), suitable for ultra-large refrigeration needs, and the efficiency is extremely high (especially under full load conditions).
Simple structure, few moving parts, reliable operation, and low maintenance cost.
After adopting frequency conversion technology, the regulation performance under partial load is also good (such as 30%~100% load regulation).
Disadvantages:
High initial investment cost and strict requirements on installation accuracy.
"Surge" phenomenon (periodic oscillation of air flow, damage to equipment) may occur at low load, which needs to be avoided by anti-surge control logic.
Application scenario
Large central air conditioning system (such as airports, large data centers), large industrial refrigeration (such as petrochemical and metallurgical industries).