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Researchers at the University Jaume I put environmentally-friendly refrigerants to the test

June 28, 2004

Keeping food cool in the fridge or switching on the air conditioning at the office can be costly for the environment. The gases that have been used up till now for refrigeration (mainly the so-called HCFCs, such as R22) contain high proportions of chlorine, one of the elements responsible for the depletion of atmospheric ozone. Manufacturing new refrigerating equipment that requires the use of these gases is now forbidden by law and new ones have therefore been designed that have less impact on the environment. These new products are known as environmentally-friendly refrigerants. Yet the companies that install these systems are still wary about whether these new compounds perform as well as their predecessors. Researchers from the Area of Heat Engines and Movers at the University Jaume I (Castellon, Spain) have managed to dispel such doubts in a study that shows that these gases behave in a very similar fashion to the ones they are to replace.

The researchers submitted the new products belonging to the HFC family (more specifically R407C and R134A) to a compression cycle in order to study a series of parameters, such as cold production and energy consumption, and then compared this information with the results obtained from analyses of gases from the HCFC family that have been used up till now.

"The so-called environmentally-friendly gas R407C has been seen to offer the same performance specifications and behaves in a very similar manner to R22. The study has also allowed us to rule out one of the potential disadvantages of R407C, that is, the loss of efficiency resulting from possible variations in the composition of the gas due to leaks," explains Joaqu'­n Navarro, the lecturer in charge of the project, together with Ram'³n Cabello.

"R407C is a compound made up of a mixture of three gases in very strict proportions, each of which has its own volatility. A leak in the two-phase zone could therefore give rise to variations in these percentages because not all the gases would be lost at the same rate. Our analyses have proved, however, that this phenomenon is not significant," adds Navarro.

Nevertheless, this concern for leakages is no trivial matter. Although environmentally-friendly refrigerants do not deplete the ozone layer, they do play a part in worsening the greenhouse effect (with potentials that are 1700 times higher than that of carbon dioxide, in the case of R407C). It is precisely for this reason that the researchers at the Area of Heat Engines and Movers are now going to investigate the use of carbon dioxide as a possible substitute for the gases currently employed for these purposes. "Our aim is to carry out experimental analyses of the behaviour of CO2 and the technology associated to its use as a refrigerant both in industrial refrigeration and air conditioning applications and then to compare results with those from the HFC family of compounds. The chief advantage of using this gas would be that its only contribution to the greenhouse effect is that derived from the electrical power it uses," concludes Joaqu'­n Navarro.

Universitat Jaume I