What characteristic should oils used as heat transfer fluid in a hot oil system possess?

For oils used as heat transfer fluids in a hot oil system, possessing high heat transfer characteristics is vital. This is because the primary function of the heat transfer fluid is to efficiently transfer heat from one location to another—whether that's from a heat source to a process or equipment that requires heating.

A fluid with high thermal conductivity will enable more effective and quicker heat transfer, allowing the system to operate more efficiently. This helps maintain the desired operational temperatures and enhances the overall performance of the system. Without high heat transfer characteristics, the heating process could become inefficient, leading to increased energy costs and potential overheating or underheating of processes.

While low viscosity, low boiling point, and non-flammability are also important considerations when selecting a heat transfer fluid, the greatest priority in this context is having a fluid with excellent heat transfer capabilities, as this directly influences the system's efficiency and effectiveness.