Advances in liquid coolant technologies for electronics cooling

There are several liquid coolants existing today. Among these, some are based on old technologies and the others are based on new advancements. All these liquids have been divided into six chemistries and a methodology has been presented to compare their overall efficiency, which was determined from heat transfer rate as well as pumping power requirements in microchannels. It was found that potassium formate (PF) solution exhibits the highest overall efficiency among the coolant chemistries evaluated. Other factors such as flammability, toxicity, corrosivity and electrical conductivity have been discussed in reference to these coolants. Based on electrical conductivity, liquid coolants have been divided into three categories: (1) liquid in which direct immersion cooling is possible; (2) liquid in which direct immersion is not possible but a leak or a spill will not damage the electronics; and (3) liquid in which neither direct immersion nor leakage is tolerable.