On September 27th, the scientific and technological achievements evaluation team composed of more than a dozen authoritative experts, including Jiang Yi, academician of the Chinese Academy of Engineering, Academician He Yaling of the Chinese Academy of Sciences, Luo Jijie of the Air Force Engineering Design Institute, and Li Jiang, president of Hefei General Mechanical and Electrical Products Testing Institute, were unanimous in Zhuhai, Guangdong. It is recognized that the "efficient home multi-connection based on large and small volume switching compressor technology" is the first in the world and achieves the "international leading" level; "the research and application of CAN+ communication technology for multi-connection" has reached the "international leading" level, and unanimously agreed. These two projects are assessed through scientific and technological results. This means that China has successfully overcome the worldwide problem of frequent shutdowns of central air-conditioning, and achieved significant improvements in performance, and achieved new breakthroughs in multi-line communication technology.
Jing Huaqian, deputy secretary-general of the China Refrigeration Society, said that “multiple connections†have become the choice of more and more families. It does not occupy a place, and a single host can cover multiple rooms. However, according to big data research, China's households use more online nights than in the daytime, and the operation of one indoor unit alone accounts for 60% of the total running time, and the time of running 1-2 internal machines accounts for the total running time. 87%. In other words, most of the time, multiple connections are running under low load conditions.
The multi-line load design is based on the whole house heat load, so the displacement of the compressor will be large. When the single-open 1p indoor unit is running, the minimum output value of the compressor is large, and it is very easy to stop at the temperature point. At this time, the multiple connections will be lost. The adjustment advantage possessed by the inverter will be the same as that of the fixed frequency machine, and will not stop the shutdown, resulting in large room temperature fluctuations, resulting in low compressor efficiency.
Shi Wenxing, a professor at Tsinghua University, said that the frequent shutdown of central air-conditioning is a worldwide problem. How to improve the energy efficiency of home multi-line operation under low-load operation? Gree researchers have innovatively developed a new type of compression based on large and small volume switching technology. The compressor can select the operating mode according to the system load condition. In the low load mode of operation, only small volume cylinders are operated, large volume cylinders are unloaded, and the minimum output value of the compressor is greatly reduced, thereby improving comfort and energy efficiency. In the high load mode of operation, the two cylinders operate simultaneously to meet high load requirements. Since the compressor cylinder volume can be changed, the energy efficiency at low load and the minimum output value are reduced.
In addition, with the increasing use of multiple online stores in large shopping malls, buildings, industrial parks, etc., the demand for centralized control of hundreds of units is increasing. The traditional master-slave communication network has a slow response speed when controlling many units at a time, and the problem of unsuccessful control is prominent, and the number of units is more obvious. This time, China successfully developed the “Research and Application of CAN+ Communication Technology for Multi-connectionâ€, which can complete the automatic address allocation of hundreds of nodes in large multi-line system in just a few seconds, changing the “minute level†of traditional multi-line communication network. Time limit, realize the self-organizing network of the network, free of debugging, simple maintenance and reliable operation.
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