CO2 has become the refrigerant of choice for many applications. In most cases it provides better COP levels than previously adopted HFC technology.

That being said, thorough knowledge and proper system design is mandatory when approaching CO2 tech, due to the unique thermodynamic characteristics of this refrigerant.
CO2 is one of the oldest solutions in the HVAC&R sector. Its environmental impact is zero and in various applications it allows significant energy savings. However, its thermo-fluid dynamic characteristics require the introduction of dedicated components, very different from what is commonly used with HFC refrigerants.

In Dorin, the refrigeration compressor, which has always been the most stressed component of any system, has undergone a profound technical review, aimed at introducing numerous solutions widely used in sectors that are much more technologically advanced, such as the automotive. CO2 imposes a series of challenges, such as very high thermal stresses (discharge temperatures up to 200°C), high differential pressures (up to 8 times higher than in HFC applications), very small bores, with consequent extraordinarily high specific loads in correspondence with the small connecting rod eye, and extreme solubility with lubricants, imposing cutting-edge tribological solutions.

Dorin, who has always believed in this innovative technology, today boasts the widest range of CO2 compressors worldwide, achieving successes and acclaim in numerous system configurations and becoming the undisputed protagonist in the technology and production of CO2 compressors. The road that has led and is leading to this success has been paved with numerous technical challenges, constant fine-tuning and huge investments in research and development. Dorin decided to develop a new compressor platform, completely dedicated to the use of CO2, therefore not limiting itself to a simple adaptation of the machines for HFC, investing huge capitals in the engineering of a product, whose sole focus was CO2, bearing in mind all the challenges described above and guaranteeing the market the best product available in terms of reliability and efficiency.

Among the numerous cutting edge technical solutions adopted, we can highlight:

• External discharge manifold, which guarantees convection phenomena between the manifold itself and the surrounding environment, leading to lower thermal levels, even of the lubricant inside the compressor and to extremely higher reliability.
• Piston made with a material with the same characteristics as that of the compressor body, allowing for congruent thermal expansion between the piston and the body, and drastically reducing the possibility of seizure.
• Piston pin, coated with a thin layer of extremely hard material, characterized by a very low friction coefficient and self-lubricating.
• Connecting rods that have a viper-shaped head, with increased lower support to decrease the specific load at the moment of the compression thrust.
• Multi-layer bushings with a tough and resistant metal matrix, coated with hardened plastic material, characterized by a very low friction coefficient and self-lubricating.
• A generously sized oil pump, which manages to bring oil under pressure to all parts of the compressor, including the piston pin.

It clearly emerges how Dorin is able to offer the market CO2 compressors characterized by a significantly advanced technological level, guaranteeing users extreme system reliability and low operating costs.