The heating technique of solids, liquids or gases in industrial systems is of indirect type. This technique involves the use of a thermal carrier (heat transfer oil) that takes heat from a hot source (heat generator) and transfers it where needed. Despite higher costs and operative complexity, several advantages are achieved by an indirect heating system. For example the greater ease of temperature control and uniformity and the ability to serve more users by a single heat source. Also safety is maximized because users are not directly in contact with the heat source. Eni heat transfer oils are formulated with high quality base oils to ensure excellent heat transfer and a long term protection of the circuits against corrosion and deterioration.