Disclosed is an immersion cooling unit including an immersion cell, defining an internal cavity. An electrical component is positioned in the internal cavity. A dielectric working fluid partially fills the internal cavity and at least partially immerses the electrical component. A condensing coil is positioned above the dielectric working fluid. The dielectric working fluid comprises at least one of 1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene, (HFO-153-10mczz), or 1,1,1,4,5,5,5-heptafluoro-4-trifluoromethyl-2-pentene, (HFO-153-10mzzy). Also disclosed is a method of cooling an electrical component, comprising partially immersing an electrical component in a working fluid; and transferring heat from the electrical component using the working fluid.