Peter Powell

The world of refrigerants currently revolves around HFCs, ammonia, and CO2. But what about hydrocarbons such as propane, propene, and isobutane? They’ve been around seemingly forever and have many advocates.

How might those hydrocarbons fit into the equation? Well, the answer probably relates more to geography than chemical formulas.

Eurammon - a joint European initiative of companies, institutions, and individuals - has come out with a report highlighting some interesting applications that certainly find HCs entering into technology we are all familiar with.

Here are some examples from a recent Eurammon report, each followed by my comments and then some general thoughts at the end.

Eurammon: The Chinese air-conditioning system manufacturer Gree Electric Appliances is one of the companies using propane to replace R-22 and HFC-410A in new systems. In late 2009, Gree, assisted by the implementing agency GTZ Proklima, started pilot production of room air-conditioning systems based on propane. In addition to the reduced charge size, GTZ Proklima with UK-based consultant Daniel Colbourne, assisted with the safe design of the air-conditioners. China’s entire air-conditioning industry and beyond is being funded by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety within the framework of the International Climate Initiative based on a decision of the German Federal Parliament.

My Comment: For one, it is interesting that German assistance is going into a Chinese project, which gets back to one aspect of my geographical contention. And did you catch the words “safe design”? More on that later.

Eurammon: Companies in other industries are also opting for hydrocarbons, such as the British fruit grower Mansfields. The family company stores apples and cherries in a controlled atmosphere so that they will be available in top quality all year round regardless of when they were picked. The refrigeration experts International Controlled Atmosphere Storage and SRS Frigadon designed a propane secondary refrigerant system completed in 2008 with an output of 1,150 kW. Five air-cooled factory-assembled packages charged with altogether 90 kg propene provide refrigerating energy for the secondary circuit at a temperature of -9°C. The special safe design of these chillers and a detailed safety analysis was provided by Re-phridge.

My Comment: Well, here is propane moving into refrigeration over in England. And, there are those words “safety analysis.” Keep that in mind.

Eurammon: One important process in the research and production of biotechnological products is freezing and defrosting substances for transport and storage. At the pharmaceuticals company Roche, this takes place in tanks that are cooled down to -40°C in a clean room atmosphere. Peter Huber Kältemaschinenbau developed a chiller that works with a small charge of 1.8 kg propene. The core element of the system is a two-stage semi-hermetic reciprocating compressor, which is designed for use with propene. After being brought down to a temperature of -60 to -30°C, the propane then cools the silicone oil circulating in the cooling jacket. The output is 12 kW at a secondary refrigerant outlet temperature of 0°C, and 6.5 kW at -40°C. The safety concept of the system comprises separate refrigeration circuits into several sections so that in the event of a burst pipe, any refrigerant leak is limited to the affected section rather than the complete charge.

My Comment: Aspects of transport refrigeration enters the picture along with the term “safety concept.”

HOW SAFE

Three case histories; three references to safety.

The safety issues relates to the flammability of hydrocarbons. Acknowledging that is Monika Witt, chair of Eurammon. “Certain requirements have to be met when using these substances. Potential sources of ignition have to be identified and eliminated early during the planning phase. The systems have to be designed so as to avoid leaks: this includes reducing the number of joints and applying permanent corrosion protection. As far as possible, the refrigeration system should be installed on the roof or equipped with a gas detection and ventilation system so that the gas can be exhausted in the event of a leak. But even if the flammability of hydrocarbons pose the greatest challenge, these substances can still be handled safely, as demonstrated every day in thousands of refueling stations all over the world.”

All that may work worldwide - except for the United States and Canada where the flammability issue has curtailed the possibility for many such projects. That is the geographical point I want to make.

To get greater attention for such flammable hydrocarbons here, some questions need to be addressed:

• What are the upfront costs for the configurations of such projects?

• How do they get an A-1 safety rating that is the preferred rating in the States?

• And what about the plethora of ready to sue lawyers we have?

In some cases, it is not a global marketplace with everybody on the same page.

Publication date: 01/11/2010