HEAT TRANSFER OILS also known as Thermic fluids are finding many applications in industry for their ability to transfer heat. This is not only on the grounds of safety but also by the fact that more accurate control of temperature can be achieved as the risk of localized overheating is avoided when compared to direct heating.

Thermic fluid boilers are popular in industry and are fast replacing steam boilers in certain applications because of the following advantages:

- Exemption from Indian Boiler Regulations act and related formalities.

- No need for water treatment.

-No problem of scale deposition on heat transfer tubes.

- Safety from explosion hazards due to low operating pressures.

- Heating medium being a liquid, higher efficiency of heat utilization can be achieved.

SELECTION

Right selection of thermic fluid is extremely important because it is this factor which profoundly contributes towards ensuring reliability of performance of heat transfer system. A good thermic fluid should have the following properties.

- The oil should be thermally stable.

- It must possess excellent oxidation stability.

- The oil should not have too much viscosity drop during its hot run hence should have sufficiently high viscosity index.

- The specific heat should not exceed 0.70 Kcal/kg/deg C at high temperature, as otherwise the thermic fluid may loose its heat rapidly.

- It should have a reasonably low pour point so that the system does not get wax clogged at low ambient temperatures.

- It must have low volatility characteristics.

- Good corrosion preventive properties.