Figure 1: The engineer is installing the units for the air conditioner.
The scroll compressor was invented in 1905 by a Frenchman, Copeland. He set up Copeland company in the United States, where water air conditioners are mostly used, so the compressor is mainly used in air source heat pump or ground source heat pump, as well as other commercial fields.
Copeland was acquired by Emerson Electric in 1986, so it is now a unit of Emerson, which makes precision air conditioners as well as compressors. Now Emerson has also launched a new type of combined supply system at a high price.
It is like the fluorine air conditioner. It may affect HVAC companies with technical strength, because the new system can be developed by these companies. Whether the system is good or not depends on the technical strength of the HVAC company, unlike the quality of fluorine air conditioner guaranteed by the selected brand.
The rotary compressor was pioneered by Toshiba, the earliest single rotor type was introduced in 1967, and the mainstream twin rotary type was introduced in 1988. And this year's tri-rotor type is applied for its latest U-series models. So in the field of rotary compressors, Toshiba's position and scroll technology as well as Copeland, is the benchmark.
During the 20-year protection period for Toshiba's patented twin-rotor technology, other companies' air conditioners were mostly scroll type. Many people suggest that the twin rotary compressor can not be used for high-power air conditioners.
In fact, however, Toshiba's largest twin-rotor air conditioner is 14P, and its current tri-rotor is 24P. By patent protection, other air conditioner companies have not been able to produce tri-rotor type air conditioners larger than 6P.
Figure 2: The cutaway hermetic rotary compressor.
The scroll compressor is high efficiency when running at a high speed, and low efficiency at low speed. Scroll varied-frequency compressors operate at a minimum power of 30% of rated power, depending on the technology of the company producing the air conditioner.
The rotary compressor of high speed or low speed, the efficiency of which is almost the same, and more stable. In other words, it is not as efficient as the scroll type at a high speed, but it is more efficient at a low speed.
The minimum operating power of the rotary varied-frequency compressor is 10% of the rated power, depending on the technology of the company producing the air conditioner.
After knowing these two points of description, we will focus on the actual use of scroll and rotary compressors in air conditioners.
Air conditioners are divided into water air conditioners and fluorine air conditioners. Among them, water air conditioners are mainly used in the United States, while fluorine air conditioners are mostly used in China, Japan and South Korea. And water air conditioners gradually walked into the flat.
Internal and external units are independent of each other, and they can be the same brand, or not the same brand. When the air conditioner is running, the outdoor unit is basically at full load, which is not adjusted according to the situation of the indoor unit, so it also conforms to the characteristics of the scroll compressor.
Figure 3: The outdoor unit of the water air conditioner.
Therefore, most of the water air conditioners apply scroll compressors. Copeland compressors account for more than half of the share in the field of scroll type, which is also mainly because of the American share. Water air conditioners are mainly used in large industrial and commercial places, such as shopping malls, star hotels, etc.
The internal and external units have the protocol, and they must be made by the same manufacturer. For example, Toshiba's outdoor unit is not suitable for Daikin's indoor unit. The advantage of the protocol is that the output power of the external unit can be varied by the internal unit load, which is the embodiment of the frequency conversion function.
For example, a 6P air conditioner, of which there are an outdoor unit and 5 indoor units. Generally speaking, a maximum of 3 indoor units are open at the same time, or two in the living room and one in the dining room at the same time. Of course, it depends on the number of people in the home, and the situation between a family of 3 and a family of 5 is not the same.
If the scroll compressor is used, the number of opening internal units is small, it will be inefficient. Especially when only one internal machine is opened, it even results in waste. It’s because scroll type frequency conversion air conditioners can usually be reduced to 30% of the rated power at the lowest, (6P to 1.8P). If a machine is opened (1P), 0.8P will be wasted.
If the rotary compressor is applied, the minimum can be reduced to 10% (6P to 0.6P). Therefore, even if a 1P air conditioner is started, it can also be fully matched with no waste. This is the advantage of rotary compressors in practical applications.
So when Toshiba's patent protection ended, other air conditioner brands began to produce rotary types. Daikin slightly modified the rotary type and named it the swinging type, but the principle is the same.
The above uses air conditioners with low power as examples. If it is a 12P air conditioner with an external machine and five internal machines, the waste is serious. In a word, if your home is equipped with a water air conditioner, the scroll type will be good; If it is a fluorine air conditioner, the rotary type is appropriate.