Industrial Coolants and Its Uses
Coolant is that type of substance that is used for reducing or regulating the system’s temperature that comes in gas or liquid form. 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. As a matter of fact, few applications for such need it to be good electrical insulator too.
While coolant is typically referred to HVAC and automotive applications, the industrial coolant is much more of a technical as it’s found in heat transfer fluid frequently used for low as well as high temperature for the manufacturing applications. This term covers cutting fluids too. Coolants might be able to stay on its phase, gaseous or liquid or it can even undergo a transition with latent heat that adds to the efficiency of cooling. Now say for example that the latter is put into use to achieve below ambient temperature, then it is known as refrigerant.
A common type of coolant in the market is air. Air cooling is making use of either forced circulation by using fans or convective airflow or otherwise known as passive cooling. Hydrogen is being used as well for high performance gaseous coolant. The thermal conductivity is a lot higher compared to all other gases, it has low density and high specific heat density and as a result, low viscosity which is actually a benefit for rotary machines that are vulnerable to windage losses. Hydrogen cooled turbo generators are widely used for electrical generators in big power plants at the moment.
As for nuclear reactors that are gas cooled, what is used in this purpose is inert gases. Helium basically has low tendency to absorb neutrons and for that, the odds of it becoming radioactive is less. Actually, carbon dioxide is also used for mixing it with AGR reactors and Magnox. Sulfur hexafluoride on the other hand is being used for cooling and insulating high voltage power systems similar to switches, transformers, circuit breakers and so on. Steam can also be used where there is high specific heat capacity required in gaseous form.
Water is another common type of coolant. 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. Betain however is made using pure plant juice but is likely similar with water coolants. Pure de-ionized water is used for cooling electrical equipment due to its low electrical conductivity.