Introducing a Quieter Technology for Rotary Compressors

Rotary compressors are the beating heart of many home air conditioners. But as our demands for efficient and powerful cooling grow, so too does the need for innovation. In response, LG has developed a new rotary compressor, promising to improve performance and energy consumption.   

It is a fairly intuitive expression. In the case of the rotary compressor structure, the process of low-pressure gas sucked through the rotation of the eccentrically designed shaft and roller is compressed to high pressure and discharged repeatedly. In the process, the part that is in constant contact with the roller and separates the low-pressure and high-pressure sides in the cylinder is called a vane.
The recent development trend of inverter products is to minimize power consumption through low-speed, low-load operation. Due to the characteristics of the rotary compressor, when operating at low speed and low load, sufficient back pressure on the high-pressure side is not formed, so the vane does not contact with the roller during rotation, failing to form a compression chamber, and generating a noise due to momentary contact with the roller.
To solve this problem, a vane was structurally designed to be inseparably combined with a roller, and as its structure is similar to a hinge, it led to the birth of the name 'Hinged-Vane'.

One of the biggest advantages of the Hinged-Vane Rotary Compressor's structure is the improvement in noise during low-speed operation. In the case of noise at low speeds, it is difficult to judge and manage noise because it is not simply a dB measurement but a sensitive noise felt by the user. In the case of rotary compressors, the number of products located in homes or indoors. such as wall-mounted air conditioners, dryers, and water heaters is increasing, the number of noise complaints from users is also increasing. Various steps and management points were added to all stages such as design, tolerance management, manufacturing, and production. This was because it was concluded structurally necessary, considering the needs of the product and the market.
Besides that, as a result of testing applied to a 12k Btu RAC product has been confirmed that the performance has improved under standard cooling and heating conditions at low Hz. When measuring energy efficiency by country or region, seasonal evaluation is applied, evaluating performance under various conditions to make a comprehensive judgment.
As mentioned earlier, in a rotary compressor with a general structure at low speed and low load, it is difficult to maintain constant contact with the vane, so the compression chamber is not formed, and it is impossible to secure performance at low speeds due to refrigerant leakage and increased power consumption. Therefore, this problem can be solved by applying the Hinged-Vane structure.

Taking a wall-mounted air conditioner as an example, when an end user uses the air conditioner, the compressor operates at a high speed to reduce the difference between the indoor temperature and the air conditioner's set temperature. Then, when the set temperature is reached, the compressor's rotation speed gradually decreases and operation is maintained at 10 to 20 RPS to minimize power consumption.
It is operated at low speed and low load. In this case, the back pressure on the high-pressure side of the cylinder is not sufficiently formed, so due to the structure of a general rotary compressor, the vane and the roller are not in constant contact in the relevant frequency band, and a phenomenon occurs where they collide while rotating, and this collision sound is transmitted to the user as an abnormal noise. In particular, the noise becomes more noticeable due to the quieter surrounding environment when the air conditioner is turned on during sleeping hours.

An internal evaluation is done by an outsider rather than an evaluation by LG’s internal personnel. Among the projects currently underway with this model, LG’s client needed verification of noise at low Hz, so they visited the LG factory in person to observe the experiment, and the project received more satisfactory feedback than expected. Plus, hundreds of compressors have completed short- and long-term evaluations to verify the reliability of the new structure, and field testing of air conditioners has been in progress in multiple countries for several years now. And no major problems have been encountered so far. 

LG's introduction of the Hinged-Vaned Rotary Compressor marks a significant step forward in refrigeration technology. It not only reduces noise levels but also demonstrates improved energy efficiency across various operational conditions. With ongoing field testing and consistent performance, LG's new compressor is poised to set a new standard in the market, providing quieter and more efficient cooling solutions for consumers worldwide.