Differences between structure and working principle
scroll compressor relies on a pair of intermeshing involute scroll discs (fixed disc and moving disc) to form multiple closed crescent-shaped chambers, and realizes continuous gas compression by rotating the moving disc around the fixed point. Screw compressor uses two rotor with spiral tooth groove (male rotor and female rotor) to mesh and rotate, so that the volume between teeth is periodically reduced to complete the process of suction, compression and exhaust.
Energy efficiency comparison
- medium and small cooling range (usually ≤ 150 kW), scroll compressor is generally more energy efficient at full load and part load due to no clearance volume and short leakage path;
- under heavy cooling condition (> 200 kW), screw compressor has more advantages with wide capacity adjustment range and stable high load efficiency;
- in frequency conversion applications, the mechanical loss of scroll models is low when they start and stop frequently, while screw machine models can achieve 10-100% stepless capacity control under sliding valve or frequency conversion adjustment.
Operational characteristics and reliability
scroll compressor has small vibration, low noise, few moving parts and long theoretical life. However, it is sensitive to liquid hammer and impurities, so it is necessary to strictly ensure system cleaning and oil return. The screw compressor has strong resistance to liquid strike and is suitable for complex working conditions. However, the precision of the engagement surface between the bearing and the rotor is required to be high, and the maintenance needs professional support.
Typical application scenarios and selection suggestions
- applicable scenarios of scroll compressor:small and medium-sized commercial air conditioners, heat pump water heaters, precision constant temperature equipment, modular units and other applications sensitive to silence, energy efficiency and installation space;
- applicable scenarios of screw compressor:large central air conditioning system, industrial refrigeration, low temperature refrigeration, long-term continuous high load operation or large temperature difference conditions.
Key considerations for selection
the actual type selection should comprehensively evaluate the cold demand range, load variation law, ambient temperature range, installation space and noise reduction requirements, system oil return conditions and later maintenance capabilities. A single parameter (such as COP) cannot replace the performance matching analysis under all working conditions.