Solutions for the use of CO2 in commercial refrigeration

The interest surrounding the use of carbon dioxide (CO2 R744) in refrigeration systems derives from the need to reduce environmental pollution, especially as regards the formation of the hole in the ozone layer and the increase in the greenhouse effect.
The importance of these aspects is also a result of more than 160 countries signing up to "Kyoto Protocol", an international treaty on the environment.
The treaty obliges above all the industrialised countries to reduce polluting emissions (carbon dioxide and another five greenhouse gases) by no less than 5.2% below the 1990 levels (considered as the reference year), in the period from 2008 to 2012.
In addition to Kyoto, various countries also have enacted a series of directives and legislation whereby in the coming years all refrigerants with a high environmental impact will be gradually phased out.
From this point of view, two forms of pollution need to be considered: direct, mainly due to refrigerant leaks released into the atmosphere; indirect, due to the generation of energy for the operation of the systems.
The latter is therefore related to the energy efficiency of such systems. The direct contribution involves two aspects: potential damage to the ozone layer and contribution to the greenhouse effect.
The refrigerant fluids that most minimise this direct contribution and should therefore be taken seriously into consideration are natural fluids (that is, already found in nature): hydrocarbons, ammonia and carbon dioxide.

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