Reader Feedback

Boy-oh-boy am I confused. In the July issue of PLANT ENGINEERING on Page 16 you have a article concerning CO₂ and its use as a refrigerant. I quote:

“Because of its good environmental properties and relative safety, there is renewed interest in carbon dioxide as a refrigerant … But it is now coming back as a natural refrigerant with no ozone depletion potential and very low global warming potential.”

Well I just saw the movie “An Inconvenient Truth” and it certainly implies that CO₂ does not have good environmental properties and has a very high potential for global warming.

So, can someone unconfuse me?

Albert Peterson

Broward County, FL

The first step in answering this confusion is to clarify the Global Warming Potential (GWP) from refrigeration of any kind.

The major source of GWP emissions are from the CO₂ generated by power plants that produce the electricity that powers the refrigeration systems.

The next consideration deals with the refrigerants themselves, hydrofluorocarbons have about 1,400 times more GWP than the same quantity of CO₂ making CO2 seem relatively harmless by comparison.

CO₂ refrigeration manages to be an excellent choice for the future because the amount of CO₂ released from the various applications is miniscule compared to that released by power plants, and the high Coefficient of Performance (COP) of CO₂ ensures that less power will be needed thereby reducing the amount of CO₂ emissions. The same holds true for other natural refrigerants such as ammonia, propane and water.

While I have not viewed “An Inconvenient Truth”, it is my understanding that the documentary deals with global warming - causes and concerns for the future. Global warming gases are water vapor, carbon dioxide, nitrous oxide, methane, CFC’s and other trace gases.

The engineering community and government regulations continue to strive to reduce both GWP gases and Ozone Depleting Gases, but we must also realize that the health of the global community needs refrigeration to maintain the cold chain to ensure the freshness of food and vaccines.

Ron Vallort

ASHRAE Presidential Member