PHOSPHATE TESTER HEAT TRANSFER FLUIDS AND THEIR USE IN AN IMMERSION COOLING SYSTEM

A heat transfer fluid for immersion cooling of electrical componentry includes a mixture of certain trialkyl phosphate esters and triaryl phosphate esters. Also disclosed is an immersion cooling system employing the heat transfer fluid and a method of cooling electrical componentry using the immersion cooling system. The mixture of phosphate esters of the present disclosure exhibits favorable properties in a circulating immersion cooling system, such as low flammability, low pour point, high electrical resistivity and low viscosity for pumpability.