@Air Compressor
2025-04-17
Comparison of screw compressor and scroll compressor
Screw compressors and scroll compressors are two common displacement compressors. They have significant differences in structure, working principles, performance characteristics and application scenarios. The following is a detailed comparison from multiple dimensions:
1. Structure and working principle
| type | structural composition | working principle |
|---|---|---|
| screw | Consists of a pair of intermeshing male and female rotors, bearings, shells, etc. | As the rotor rotates, the volume between the teeth gradually decreases and the gas is compressed and discharged |
| scroll | It consists of a movable scroll, a fixed scroll, an eccentric shaft, an anti-rotation mechanism, etc. | The moving scroll coils around the fixed scroll and makes planar motion, forming a continuous change in the closed volume and realizing gas compression. |
key differences：
- The screw type relies on rotor engagement to achieve compression, and the scroll type forms a compression chamber through the relative movement of the scroll plate.
- The screw type has clearance seals, and the scroll type relies on precision machining surface contact seals.
2. Comparison of performance characteristics
| indicators | screw compressor | scroll compressor |
|---|---|---|
| efficiency | The gas volume is less affected by pressure, but the leakage loss increases when the single-stage pressure is high. | No suction and exhaust valve, high efficiency, but limited compression ratio (usually ≤8) |
| noise and vibration | Smooth operation with low noise (65-75dB) | Lower noise (55-65dB), known as the “ultra-static compressor” |
| reliability | Simple structure, few parts and high reliability | Fewer moving parts and long life (maintenance-free design) |
| adaptability | Forced gas transmission, strong adaptability, can convey liquid-containing gas under pressure | Sensitive to impurities, breathing gas needs to be strictly filtered |
| gas transmission coefficient | Higher (0.7-0.92), injection improves seal | Continuous suction, high gas transmission coefficient (no clearance volume) |
3. Analysis of advantages and disadvantages
| type | advantages | disadvantages |
|---|---|---|
| screw | 1. High reliability and long life (design life of the main engine is 30 years) 2. Strong adaptability, can convey liquid-containing gases under pressure 3. Flexible adjustment of gas transmission volume (slide valve adjustment) |
1. High cost and strict processing accuracy requirements 2. Large size and not suitable for miniature scenes 3. Limited single-stage pressure ratio (usually ≤10MPa) |
| scroll | 1. Efficient and energy-saving, high energy efficiency ratio 2. Low noise, smooth operation 3. Compact structure and light weight |
1. High processing precision requirements and high cost 2. Low compression ratio, difficult to use in high-pressure scenarios 3. Sealing relies on processing accuracy and has weak resistance to impurities |
4. Application scenarios
| type | typical application | Not applicable scenarios |
|---|---|---|
| screw | 1. Air conditioning and refrigeration of large commercial buildings and industrial plants 2. Chemical process, natural gas pressurization 3. Scenarios requiring multiphase hybrid transmission or high reliability |
Micro compressor, ultra-high pressure (>10MPa) scenarios |
| scroll | 1. Household/commercial air conditioners, heat pumps 2. Automobile air conditioning, small refrigeration equipment 3. Precision instruments that pursue low noise |
High-pressure, impact-containing or liquid impact scenarios |
5. Selection suggestions
- Priority is given to screw type：
- When high reliability, long life and multiphase mixed transportation capabilities are required.
- Used in large industrial or commercial refrigeration systems.
- Preference is given to scroll：
- Pursuing small and medium-sized scenarios with low noise, high efficiency and energy conservation.
- Applications that are sensitive to space and noise such as household air conditioners and car air conditioners.
summary: Screw compressors are known for their reliability and are suitable for complex working conditions and large cooling capacity requirements; scroll compressors are known for their quietness and efficiency, making them more suitable for small and medium power and noise-sensitive scenarios. The selection requires comprehensive judgment based on specific working conditions, cost budget and long-term maintenance needs.