Where are Industrial Coolants Used?
Coolant is a kind of substance that is either in gas or liquid form that’s being used to regulate or reduce temperature of the system. The ideal coolant is something that has low viscosity, low-cost, chemically inert, non toxic, has high thermal capacity and neither promotes nor cause corrosion of cooling system. Some of its applications require the coolant to be electrical insulator as well.
When the term coolant is used, we often associate it to automotive as well as HVAC applications but industrial coolant is a lot different since it’s more of a technical aspect and used generally in low and high temperature manufacturing applications. At the same time, the term is used to cover cutting fluids. Coolants may stay on its phase, gaseous or liquid or, it may undergo a transition with latent heat adding to efficiency of cooling. When the latter is used to attain below ambient temperature, it is called automatically as refrigerant.
A common type of coolant in the market is air. Air cooling is using either forced circulation using fans or, convective airflow otherwise known as passive cooling. Hydrogen is used too for high performance gaseous coolant. Because thermal conductivity is higher in comparison to other gases, it is expected to have low density and high specific heat density allowing it to have low viscosity which many rotary machines are taking advantage of due to its vulnerability to windage loss. Currently, many big power plants are using hydrogen cooled turbo generators in their electrical generator.
Inert gases are used as coolants for the gas cooled nuclear reactors. The helium has low tendency of absorbing neutrons and becoming radioactive. Carbon dioxide is actually used to be mixed with AGR reactors and Magnox. On the other hand, sulfur hexafluoride is used to cool and insulate some high voltage power systems like switches, transformers, circuit breakers and so on. Steam can also be used where there is high specific heat capacity required in gaseous form.
A popular type of coolant used is water. The low cost and high heat capacity it has makes it ideal for heat transfer medium. It is usually used with additives such as antifreeze as well as corrosion inhibitors. In most cases, diethylene glycol, propylene glycol or ethylene glycol mixed in water is the components of antifreeze. Betaine is of similar coolant with an exception that it’s made from pure plant juice and therefore hard to ecologically dispose or non toxic. Because of the low electrical conductivity of pure de-ionized water, it’s widely used for regulating the temperature on electrical equipment.