NUREMBURG, Germany - The most recent International Trade Fair for Refrigeration, Air Conditioning, and Ventilation (IKK) gave the industry an updated message on the battle between upstart refrigerant CO2 and the now long-established HFCs.

CO2 continues to gain an increasing presence and interest, but it still trails HFCs as the refrigerant of choice. HFCs themselves seem even more secure in Europe, thanks to pending regulations regarding greenhouse gases. (See related story on page 1 concerning regulations and certifications.) After all, you only regulate something you plan to have around for a while.

The message to North America is that even though CO2 is showing up in several industrial applications, and at least one commercial application in the United States, it’s not about to gain the preference of HFC users any time soon.

CO2 technologies showed up throughout the show floor. At the same time, HFC producers stated their case and were supported in the use of their refrigerants by numerous OEM exhibitors including those promoting wall-mounted splits, which are extremely popular in Europe.

Close to 900 exhibitors showed all kinds of refrigeration and air conditioning wares to more than 25,000 attendees at the expo, in its 27th year.

Carbon Dioxide

The status of CO2 (R-744) was best put into perspective in the 14th Edition of the “Bitzer Refrigerant Report,” a much-anticipated annual update on refrigerant trends (available in English at In its largest section to date on CO2, the report said the refrigerant could be used “very economically and with favorable eco-efficiency.”

“For example, these include subcritically operated cascade plants, but also (in) transcritical systems in which the temperature glide on the high-pressure side can be used advantageously, or the system conditions permit subcritical operations for long periods.

“In this connection, it must be noted that the heat transfer coefficients of CO2 are considerably higher than other refrigerants - with the potential of very low temperature differences in evaporators, condensers, and gas coolers,” the report stated. “Moreover, the necessary pipe dimensions are very small, and the influence of pressure drop is comparably low. In addition, when used as a secondary fluid, the energy demand for circulation pumps is extremely low.”

According to certain expo attendees, CO2 has been found viable when used with ammonia in cascade industrial refrigeration systems; and in conjunction with HFCs in secondary-loop commercial refrigeration systems. The push to make CO2 function as a stand-alone refrigerant is still a work in progress, although advocates of the approach say the equipment to accomplish this exists. Tests are being conducted.

On the expo floor, CO2 products included a range of compressors for subcritical and transcritical applications from Dorin of Italy (; commercial compressors from ACC (; compressors for a “range of commercial refrigeration purposes” from Tecumseh (; and a CO2 scroll from Emerson as part of its Copeland line ( that is undergoing supermarket pilot testing.

Components for CO2 systems included condensers, hot gas heat exchangers, and shell and coil heat exchangers from Klimal Italia (; cold plate freezers from DSI of Denmark (; stop valves, regulating valves, check valves, filters, service valves, and safety valves from Revalco of the Netherlands (; industrial valves from Hansen Technologies (; and an oil separator from Temprite (

In addition, the Institute for Air Conditioning and Refrigeration (ILK) in Germany reported on its continuing testing of two-stage rotary piston compressors using CO2.

R-410A and Other HFCs

HFCs were also given strong support at the expo. Solvay ( noted that it’s a vital refrigerant in Europe because HCFCs are on an even more rapid phaseout there than in the United States, and CO2 has yet to reach widespread use. HFCs “enable the supply of healthy food, and protect food from spoiling during storage and transport,” the company said.

HFCs are a good environmental choice because there are no ozone-depletion issues and they are energy efficient. Of available refrigerants beyond HCFCs, the HFCs are most cost effective, a company report said.

“Time is running out for HCFCs in Europe,” stated DuPont ( A report from Phil Bardsley, business manager for DuPont Fluorochemicals Europe, Middle East, and Africa, said, “Use of HCFCs like R-22 will no longer be viable and alternatives will be required.” He noted that virgin HCFCs would no longer be sold in Europe as of 2010, about 10 years before the U.S. deadline.

He said his company is recommending HFCs that work with POE oils for new installations, and HFCs that work with mineral oil (the latter of which DuPont markets under the Isceon brand name) for retrofits.

At the same time, some manufacturers suggested that HFCs that work with POEs could be used in retrofit applications, albeit with a detailed retrofit process. For example, Arkema ( suggested a retrofit procedure for R-427A (marketed by the company as FX-100 and pending ASHRAE approval). The process requires recovering the entire R-22 charge, draining the mineral oil from a system, adding POE lubricant, changing the filter-drier, evacuating the system, charging with R-427A, and restarting the system.

R-410A was also given its due. Midea ( showed 10 models of wall-mounted splits - the majority of the models it had available - that run on the HFC. Portable window dehumidifiers were also shown that run on the refrigerant.

Emerson Climate Technologies - European Headquarters ( highlighted a range of digital scrolls for both residential and large commercial applications up to 30 hp.

External inverter units for heat pumps were shown by Stulz ( that ran on R-410A and were said to be compatible with open- and closed-loop control systems. Mitsubishi Electric ( displayed inverter technology with an R-410A system.

Scroll compressors that work with R-404A were noted by Hitachi (

A condenser unit for the same refrigerant was highlighted by Danfoss ( Its Optyma Plus™ has the compressor, fan speed control, filter-drier, shut-off valve, pressure switch, magnetic contactor, and sight glass factory built for quick installation. The company also promoted R-134a with a line of Optyma™ condensing units; applications include reach-in units.

Refrigerants Naturally

Beyond CO2, other so-called natural refrigerants were given their due. Eurammon (, a joint European initiative of companies, institutions, and individuals promoting the use of natural refrigerants such as ammonia, had a booth presence.

The group drew attention to a recent statement in which the Australian government supported a natural refrigerants initiative. Refrigerants on the radar include CO2 and ammonia.

Other manufacturers showed refrigerants that were pure or blended propane and isobutene. Such refrigerants have had widespread use especially in smaller systems in Europe, but the flammability issue would probably result in a lower-than-A1 safety rating in North America, advocates said, meaning such refrigerants were unlikely to make much of an impact “across the Big Pond.”

Methods of recycling refrigerants from large systems were described in a paper from Solvay. Primary recycling involves single-substance refrigerants discharged with single-stage mobile recycling equipment. In secondary recycling, secondary raw materials are extracted from the products that need to be disposed of; then the refrigerants are decomposed in a high-temperature separation plant.

The newest entry in leak detectors was a unit with a patented Heated Pentrode™ technology designed for refrigerant-specific detection and elimination of false alarms. The product, shown by Advanced Test Products Europe GmbH (, also was said to be unaffected by rapid temperature changes.

Infringements and Imports

The issue of possible illegal activities involving refrigerants was a topic at the booth of Honeywell ( In fact, according to a statement, Honeywell “identified several exhibitors offering for sale unlicensed, infringing R-410A for air conditioning applications.”

During the expo, the refrigerant manufacturer obtained a preliminary injunction from the court in Dusseldorf, Germany, “stopping those companies from promoting and selling the infringing R-410A at the trade show.” Booth officials also expressed concern over unsafe cylinders and a refrigerant identified as R-134a, but which they said was really a mixture of four refrigerants, including R-22.

The company also supplied a statement from the European Fluorocarbons Technical Committee (EFCTC) that noticed “numerous infringements are still common practices.” EFCTC called upon the European Commission and mem-ber states of the European Union “to stay vigilant and to enforce the EU legislation vigorously.”

During the conference, representatives of the Chinese Association of Refrigeration and the German Association of Refrigeration and Air Conditioning Contractors signed an “Agreement Concerning the Protection of Intellectual Property.” In the agreement, the Chinese association said it would “make our best possible efforts [for] the protection of patents, technologies, and products,” and “denounce every possible form of infringement against intellectual property.”

Publication date:12/04/2006