On August 21, two self-developed units of Gree, Mega-kilowatt Nuclear Plant Specialized Air-cooled Screw Chiller and Water-cooled Centrifugal Chiller (inverter), were accredited as “International Advanced” by the expert panel in Zhuhai.
These two types of nuclear plant specialized units self-developed by Gree belong to national key S&T special projects, furthermore, they are the world’s first innovations in their respective fields. They represent a historic breakthrough of Gree again in the field of engineering technology for nuclear plants’ key auxiliary equipment, and also take the top spot in global central air conditioning level.
At present, China is developing nuclear power and promoting the internationalization of nuclear power development. But the designs and manufacturing technics requirements for auxiliary refrigeration equipment of nuclear power plant are extremely strict. In the past, only Trane could provide centrifugal chiller for AP/CAP series nuclear power station. After technology accumulation and independent innovation for years, Gree successfully masters the core technologies of centrifugal chiller and screw chiller to reach the world’s leading level.
High reliability and high stability are the necessary features for nuclear plant specialized units. With regard to such strict requirements, what kinds of technical highlights do Gree units possess?
I. Inverter nuclear plant specialized centrifugal chiller to improve load adjusting capacity
At present, the AP1000 consigned project adopts Trane’s centrifugal chiller that operates in fixed frequency, thus its load adjusting capacity is deficient. While the Gree self-developed Mega-kilowatt Nuclear Plant Specialized Water-cooled Centrifugal Chiller (inverter) adopts 2-stage inverter centrifugal compressor, with high efficiency, high rotational speed, and medium-high pressure inverter system of large power, which performs better in load adjustment.
II. First-innovated super low temperature operation
The AP1000 consigned project adopts foreign brand’s air-cooled chiller with cooling ambient temperature range of -17.8℃~46.1℃, which cannot satisfy the demands of domestic nuclear power plants in plans. While the Gree self-developed Nuclear Plant Specialized Air-cooled Screw Chiller can reliably operate and conduct cooling under the ambient temperature range of -40℃~46.1℃. Before then, such research was still blank at home and abroad, thus the Nuclear Plant Specialized Air-cooled Screw Chiller is initially created in the world.
III. Internationally competitive cooling capacity
Compared with general centrifugal chiller’s chilled water outflow temperature of 7℃ and cooled water inflow temperature of 30℃, the nuclear plant specialized centrifugal chiller’s chilled water outflow temperature is 4.4℃, and cooled water outflow temperature can be up to 37.8℃, therefore the cooling capacity of a single unit can be up to 7,910KW. Only certain foreign brand’s cooling capacity can be competed with Gree among the domestic and overseas central air conditioner brands in nuclear power field.
IV. Anti-corrosion, anti-shock and high performance standards
It is known that the operating service life of common units is only 25-30 years, while the required service life of nuclear plant specialized units is 60 years. Gree self-developed nuclear plant specialized refrigerating units feature the characteristics of shock resistance, wind resistance, large capacity, long service life, anti-corrosion, low energy consumption, low noise, low vibration and so on, which can ensure units’ long service life.
V. Eco-friendly refrigerant
At present, AP1000 consigned project adopts Trane’s centrifugal machine and R123 refrigerant, while according to the Montreal Agreement, R123 refrigerant shall cease to be used in 2020. Gree’s inverter nuclear plant specialized centrifugal chiller adopts eco-friendly R134a refrigerant, which is more energy-saving and sustainable.
Experts on the spot accredited with consensus that the technology of Mega-kilowatt Nuclear Plant Specialized Air-cooled Screw Chiller had reached “International Advanced” level, in which the refrigeration technology under working condition of -40℃ ambient temperature is deemed as “World Leading” level; the technology of Mega-kilowatt Nuclear Plant Specialized Water-cooled Centrifugal Chiller (inverter) had reached “International Advanced” level as well, in which the permanent magnetic motor inverter technology is in “World Leading” level.
In fact, it is not the first time for Gree to be the “avant-courier” and “pioneer” in the field of refrigeration technology. Since 2003, when the first Gree’s self-developed “Made-in-China” large centrifugal chiller came out, Gree has broken the “technical monopoly” of large commercial central air conditioner and dramatically grown up in this field.