In the past, several natural working fluids were used in refrigeration
and air-conditioning systems. However, the appearance of CFCs caused
a drastic reduction in the utilisation of those fluids. Understanding
of the environmental damage of CFCs focused attention on alternative r
efrigerants. From these, the ones that have minimum (or nil) environme
ntal impact are natural ones. This paper presents a review of the appl
ication of the main natural refrigerants, for refrigeration and air-co
nditioning systems, as an alternative to synthetic new refrigerants (H
FCs). Recent research and development in this area is analysed and var
ious cycles are considered. Copyright (C) 1996 Elsevier Science Ltd.