Today in 1984, US Patent 4483881 A was issued, an invention of Bernhard Lenz, for his “Process For Discontinuous Wort Boiling During Beer Manufacture.” Here’s the Abstract:

In discontinuous wort boiling for the manufacture of beer, the energy of the vapor arising from the boiling is used in a heat exchanger for the production of hot water. The heated brewing water is reheated in a second heat exchange process by the energy from the vapor arising from the boiling and, with this reheated brewing water, the refined wort is heated again in another heat exchange process before the boiling, whereby the brewing water which is cooled in this heat exchange process is reheated by the energy from the vapor arising from the boiling. Thus, the energy from the vapor produced during the wort boiling is fed directly back into the wort boiling process.