Water, a Refrigerant (L`eau, un Frigorigène)

In the light of the ongoing discussions about the availability and the future of synthetic or natural refrigerants "water" is the most attractive fluid for chillers and icemakers because of the low energy demand, the intrinsic safety and the low costs both for the fluid itself and for the installation.

Axial compressors are very robust, reasonably small and the chillers/icemakers fit therefore into a normal machine room. After many years of development and testing the launch of such chillers/icemakers is only months away. Ozone depletion and climate changes from synthetic refrigerants such as CFC and HFC have shed a bad light on refrigeration in in the public opinion.

Attempts to defend synthetic refrigerants have been and still are numerous and the industry keeps trying to polish up the image of such fluids. But the future of novel refrigeration has already begun! Luxemburg has banned since many years any refrigerant with OPD and GWP, Denmark has put up a law in 2001 which includes hefty taxes on HFC.

This tax is added to the price of refrigerants and lies between 17 and 44 EURO/kg for the common fluids. The goal of taxation is clear: To make GWP refrigerants unattractive because of their price. In conjunction with tax comes a phase-out scenario which shall be effective from 2006. The options for "natural" refrigerants without ODP and GWP are limited to five fluids which are ammonia (toxic), carbon dioxide (very high pressures), hydrocarbons (flammable), air (relatively low efficiencies), and water (at and above its freezing point).

The short characterization shows already that natural fluids have their specific qualities. The USA "hate" hydrocarbons because of their flammability whereas France "hates" ammonia because of its toxicity. One cannot argue such reservations despite of the fact that there is a lot of frenzy and emotions behind such arguments.

The only fluid with good efficiency, no hazards and of global availability is "water" which is, however, limited to temperatures at and above its freezing point and to capacities which make water unaffordable for small capacities.