I had the good fortune to attend the ATMOsphere America 2015 conference on natural refrigerants in Atlanta, June 25-26. I am a long-term fan of this conference (four years) and this year was the best yet. ATMOsphere America 2015 serves as the forum for discussions about the business case for natural refrigerants in North & South America.

Natural Refrigerants are compounds that occur more or less naturally in our environment and can be used in the refrigeration cycle. They are inexpensive and have little or no effect on the environment, but they do have other challenges. Natural refrigerants include carbon dioxide, ammonia, hydrocarbons (such as propane and isobutane) and for special applications water and air.

Currently the practice in refrigeration is to mostly use so-called “chemical” refrigerants. Chemical refrigerants are compounds specifically engineered to perform well in vapour/compression cycle refrigeration systems. These chemical refrigerants work very well but are very strong greenhouse gases, some as much as 4,000 times more potent than CO2.

While new chemical refrigerants are being developed that have greatly reduced global warming potential (GWP), they are also mildly flammable and very expensive. In addition, these new chemical refrigerants raise questions about other environmental and health factors associated with their use.

Natural refrigerant challenges

CO2, the bubbles in your soft drink and the stuff that dry ice is made of, is a good refrigerant as well. Its effect on the environment, in the quantities used in refrigeration systems, is tiny compared to that of current chemical refrigerants.

The challenge with CO2 is that it requires very high pressures and the refrigeration systems get complicated in warm climates. This means that in order to use CO2 as a refrigerant, the equipment can be expensive. On the other hand, CO2 systems are also generally more energy-efficient than chemical systems.

As discussed at the conference, the operational and component standards used to design CO2 systems are in need of updating, particularly to harmonise them with European standards. On the plus side, UL (Underwriters Laboratories) is working toward harmonisation of standards with the European Community under the banner of CANENA (Council for Harmonization of Electrotechnical Standardization of the Nations of the Americas).

Additional federal regulations would also help drive systems designers and components manufacturers to invest in approval testing of components. But until then, U.S. components will continue to be substantially more expensive than their European counterparts.

Ammonia, that stinky stuff we use to clean with, is also a very good refrigerant. It is very efficient, cheap, and operates at reasonable pressures. The downside with ammonia is that, in its undiluted form, it is very toxic and can be flammable. Even with these limitations, ammonia is the most commonly used refrigerant in large refrigerated warehouses and some industrial applications. In these cases, safety standards are very strict and the systems are being constantly monitored. At the conference, new designs were presented for low-charge systems that provide the same refrigeration effect with a much smaller amount of ammonia (sometimes over 90% less).

Finally, hydrocarbons are great refrigerants, low pressure and non-toxic, but as you would expect, very flammable. Flammability in a refrigeration system can be a problem if it is not handled properly. In situations where we recognise the flammability of these gases, they can be used safely (think of your propane barbeque grill). Due to their flammability, hydrocarbons are generally used in very small quantities in self-contained systems, like a refrigerator. In fact, in Europe it is common to have home refrigerators that utilise hydrocarbons as the refrigerant.

As the people at the ATMOsphere America conference work to promote the use of natural refrigerants to protect our environment and ensure the future viability of our refrigeration investments, they face roadblocks.

The primary limitations to the wider use of natural refrigerants are equipment cost, unsupportive regulations, and, as noted, standards. Cost, regulations and standards are all interwoven and it is fair to say that the U.S. is trailing Europe and perhaps the rest of the world in this regard. In fact, even the developing world, as recently represented by China, has set goals for the implementation of natural refrigerants.

While the regulations in the US are lagging those in Europe, Canada, Australia, and others as well, there is progress. On July 3, the EPA issued a ruling on the accelerated phase out of the very worst global warming potential refrigerants. While this is an incremental step, it is in the right direction.

Highlighted at the conference, the California Air Resource Board (CARB) regulators have proposed an aggressive phase down of high global warming potential refrigerants. The US, Canada and Mexico have also sponsored a proposed amendment to the international treaty on atmospheric protection (originally only including ozone depletion) called the Montreal Protocol. This proposal includes an international phase down, similar to Europe’s, of the high global warming potential refrigerants.

As the U.S. auto industry has learned with mileage and safety standards, it is always better for industry to get ahead and lead government, rather than to wait and be forced to follow unfavourable regulations.

The financial payback of these decisions cannot be ignored, but in most cases there are natural refrigerant solutions that have enough economic benefit in terms of energy efficiency to provide a payback. While the payback is sometimes longer than we would like, the technology is developing to provide better efficiencies all the time.

There are many aspects and nuances to the issues surrounding natural refrigerants that I have not discussed in this short article. But in essence the refrigeration industry and we as U.S. citizens have a choice: Continue to use the chemical refrigerants with their known environmental hazards, or make the investment in a future in which the long-term solution is known, viable and safe.

Jim Knudsen, who lives in Columbus, Ga., is an experienced refrigeration executive, specialising in global marketing, business development and product strategy. He is the holder of five U.S. patents. His Strategic Leadership Blog is located at www.jamesknudsen.com.


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