4. Conclusion

From a strictly thermodynamic point of view, the use of so-called "natural" refrigerants can be advantageously proposed to offset the bans on halogenated refrigerants. These are mainly propane, butane and ammonia. The large-scale use of these fluids must, however, be accompanied by serious consideration of the technological risks associated with them:

• the risk of scaling up installations: the greater the quantity of fluid used, the more catastrophic the consequences of a potential accident;

• risk of scale in terms of the number of small installations: we multiply the probability of occurrence of "small" accidents that can have major consequences through domino effects.

The problem posed by the assessment of technological risks associated with large industrial facilities is...