A piezoelectric actuator has a satisfactory electrical connection of a common electrode and a surface electrode without increasing the size of the piezoelectric actuator, as well as a liquid discharge head and a recording device. The fluid heating system is installed with a tankless fluid heating that includes an inlet port, an outlet port, a drain port, at least one heat source connected with the inlet port, and a valve manifold connected to the at least one heat source, the drain port, and the outlet port. Hydrogenating the at least one aromatic group in the presence of hydrogen and a hydrogenation catalyst to form a hydrogenated compound; and 3.