The Efficiency Difference Between Twin Rotary Compressor and Single Rotary Compressor

In the air conditioning system nowadays, the compressor is the core part that achieves cooling circulation, which directly determines the efficiency, stability, and lifespan of the whole machine. With the popularization of inverter technology, the compressor types are being evaluated continuously, in which "Twin Rotary Compressor" and "Single Rotary Compressor" are the two common compressor types. They work similarly in structure but differ apparently in efficiency and performance.

I. Structure comparison: Single rotary—simpler; twin rotary—more balanced

A single rotary compressor has only one eccentric rotor inside, which rotates to drive the rolling piston in the compression chamber to complete the suction and compression process, while a twin rotary compressor has two rotors that have a phase difference of 180°, operating simultaneously in the same body.

The greatest advantage of this "dual-rotor coordinated compression" structure is torque balance. The two rotors offset inertial vibrations, making the compression process smoother and significantly reducing operating noise and mechanical vibration. This design is suitable for places that are sensitive to noise, such as offices, hotels, bedrooms, etc.

II. Efficiency: Twin rotary is better for inverter air conditioners

There are two restrictions on the compressor efficiency: volumetric efficiency and mechanical losses. Single rotary compressors experience increased leakage at high speeds, significantly reducing volumetric efficiency. Dual rotary compressors use alternating compression chambers, which provide more continuous airflow and a more even compression load, maintaining higher volumetric efficiency.

Under the same operating conditions, the energy efficiency ratio (EER/COP) of a twin rotary compressor is typically 5% to 10% higher than that of a single rotary compressor. Especially under low-frequency operation (partial load), the twin rotary compressor maintains stable operation, minimizing fluctuations in cooling efficiency. DC inverter technology, high efficiency, and energy-efficient air conditioners are conducted with such features.

III. Sound and stability: Twin rotary is better

With a torque-balanced design, the twin rotary compressor has less vibration, lower noise, and less bearing wear during operation.

On the contrary, a single rotary compressor has higher eccentric loads during an operation with a longer period and higher frequency. It will increase the vibration and noise and decrease the lifespan.

So the twin rotary compressors are not only quiet but also more durable when operating. In that case, it is widely used in high-end residential air conditioners and light commercial models.

IV. Cost and Application

Twin rotary compressors have a more complex structure and require advanced machining precision, increasing manufacturing costs. For entry-level (fixed frequency) non-inverter air conditioners, a single rotary compressor is an ideal choice with good performance and considerable cost.

For higher energy efficiency, comfort, stable operation, and long-period reliability, the value of a twin-rotor compressor far outweighs the price difference.

In short, relying on their high efficiency, low noise, and stable operation, the twin rotary compressors are now steadily becoming the prior choice for high-performance inverter air conditioners. As for single rotary compressors, it is still possible to be in the top position for economical air conditioning models because they are mature and cost-effective.

Soon, with the further improvement of compressor manufacturing precision and control algorithms, the twin rotary technology will keep driving the air conditioning products towards higher energy efficiency and lower energy consumption.