10 January 1997
Natural working fluids such as ammonia, hydrocarbons, carbon dioxide, water and air, receive growing attention as sound, long-term replacements for the CFCs and HCFCs that are commonly used in today’s air conditioners, heat pumps and refrigeration equipment. As natural substances they not only pose no risk to the ozone layer, they also present little or no other threat to the environment.
In practice, the application of natural working fluids can be difficult. Some are toxic or flammable and additional costs can be incurred. Furthermore, it is always important to ensure that the efficiency of equipment is not downgraded by using new working fluids, as this could result in other negative environmental consequences. The challenge in using natural working fluids is to build safe and reliable systems, that are equal to or better than alternative systems in terms of both costs and energy efficiency.