Environmentally Friendly

Refrigeration and Air-Conditioning Technology

[ Published in HOERBIGER@MOTION 02/2012 ]

Whenever efficient refrigeration is required – be it in trade or industry, in railroad traffic or on the road – technologically sophisticated compressors made by Dorin are the first choice inItaly. The family-owned business has manufactured compressors for approximately 80 years. Thanks to the collaboration with HOERBIGER, which began in the nineties, the machines are very reliable.

The story of Officine Mario Dorin S.p.A. began in 1918, when Mario Dorin decided to invest in the mechanical engineering field and build machine tools, air compressors and liquid pumps. Soon thereafter, the refrigeration field offered interesting development prospects. After 1932 the company thus produced compressors and refrigeration system, and in 1957 Dorin started to develop semi-hermetic compressors for air-conditioning and cooling applications. At the beginning of the nineties, the first compressors with inverters were built. At the same time they were developing compressors with inverters, Dorin also developed the first compressors operated with carbon dioxide as the refrigerant. The first few years of the new millennium were shaped by the launch of the second generation of compressors for transcritical applications (CD series). The product range was also systematically expanded for the inverter applications (HI series). At the same time as these developments, the company expanded the production of compressors operated with traditional refrigerants. For example, the new HEP ECOpremium product line was created, which uses the R134a refrigerant. In conjunction with the CDS compressors, which operate subcritically with carbon dioxide, this new series is optimally suited for cascade applications. Recently, Dorin has sent another signal in favor of the continued development of environmentally compatible refrigeration and air-conditioning technology, and notably for the use of environmentally compatible refrigerants, with its HEX series, which uses hydrocarbons such as propane as the refrigerant.

At the corporate headquarters in Compiobbi near Florence, Officine Mario Dorin S.p.A. presently has more than 100 administration and production employees. The average production output is 4,000 compressors per month. Over the last few years, Dorin was able to expand significantly and now operates around the globe.

An important strategic step was the founding of a commercial agency in China. In addition to the trade business, Dorin plans to set up an assembly line of its own in China in the coming months in an effort to be even closer to the Asian customers in terms of assembly, delivery and service.

Since the company was founded by Mario Dorin, quality has been an integral part of the corporate philosophy. Officine Mario Dorin S.p.A. trusts in reliable partners during development as well as the production of the compressors. One example is the long-standing relationship with HOERBIGER Kompressortechnik GmbH in Schongau, Germany. The company has supplied fully assembled reed valves for Dorin's compressors for many years.

Dorin relies on continuous innovation to maintain the company's growth rate of the previous years. For example, the company revised key portions of the product range over the last few years. The subcritical CDS series for cascade and booster applications was completely redesigned to improve efficiency. Because of its progressive technology, the CD series continues to be regarded as the leading product for transcritical applications in the international marketplace. One aspect in the new development was the pressure control valves newly developed by HOERBIGER. Because of their consistent functionality over the entire service life, they guarantee the system's operational reliability and consequently the lasting quality of the refrigerated product. The HI series featuring inverters, which was launched in 2002, can be operated in a broad frequency range of 20 to 90 Hertz. The most impressive features of these HI compressors include high efficiency, low wear and vibration-free operation. The new HEX series is used primarily for applications with flammable refrigerants such as traditional hydrocarbons or propane. The compressors are designed specifically for hazardous and flammable environments. The new two-stage 2SH compressors equipped with four or six cylinders. are especially innovative: their key design feature is the integrated gas flow management. Because of the lower number of gaskets and connections, this compact solution minimizes leaks. The HEP ECOpremium compressors employ new technical solutions to boost the efficiency of systems which use R134a as the refrigerant. In addition, Dorin has optimized the compressor for low condensation temperatures of up to 10 degrees Celsius (50 degrees Fahrenheit) - for example by using valve plates specially developed by HOERBIGER.


The reed valves made by HOERBIGER are considered to be the most important part of Dorin's compressors: they are precision components, and their performance strongly influences the performance of the equipment. HOERBIGER supplies the reed valves as a complete module. The reeds, which are produced from high-strength spring band steel, must be both robust and elastic to achieve a long service life. Additionally, the component geometry must be optimally tailored to the use of the end product.


Dorin has produced semi-hermetic compressors for air-conditioning and cooling applications since 1957. Today, these form the company's core business. Officine Mario Dorin S.p.A. offers an entire range of semi-hermetic and open-type compressors to its global customers. The product spectrum includes more than 70 models ranging from 0.4 HP to 150 HP for use with both CFC and HCFC refrigerants. A number of two-stage compressors as well as an extensive range of accessories round out the product portfolio.


Dorin and HOERBIGER have worked successfully together on the development of valve systems since the mid-1990s. Dorin selected HOERBIGER, a worldwide innovation, technology and market leader in valve technology, primarily because of the development expertise and reliability of the products.