👉 A container fluid, also known as a working fluid or coolant, is a substance used within a system to transfer heat from one location to another. It circulates through various components, such as radiators or heat exchangers, absorbing thermal energy from a heat source and dissipating it to a sink, like the ambient environment or another fluid. This fluid can be liquid, gas, or a mixture of both, and its primary function is to maintain thermal equilibrium within the system. Common examples include water, glycol-water mixtures, and refrigerants, each chosen based on specific temperature ranges, thermal conductivity, and other properties required for efficient heat transfer.