Patent ID: 6983723

Claim:
A method for providing on-demand hot water comprising the steps of: a) providing an on-demand water heater comprising: i) a steam infeed conduit, ii) a steam flow regulator cooperating with said steam infeed conduit to regulate the flow of steam through said steam infeed conduit according to a trigger signal, vii) a steam-to-water heat exchanger operatively connected in fluid communication with said steam feed conduit and having a steam infeed and a steam outlet downstream of said steam infeed for channelling steam from said steam feed conduit through said steam-to-water heat exchanger, said steam-to-water heat exchanger having a cold water infeed and a hot water outlet downstream of said cold water infeed for channelling water to be heated through said steam-to-water heat exchanger, viii) a hot water conduit operatively connected in fluid communication with said hot water outlet, ix) a temperature sensor cooperating with said hot water conduit for sensing the temperature of hot water leaving said steam-to-water heat exchanger and for sending corresponding temperature information, x) a means for generating said trigger signal when the temperature of said hot water leaving said steam-to-water heat exchanger falls below a threshold temperature; b) providing pressurized steam to said steam infeed conduit from a steam boiler so as to re-capture waste heat in a steam circuit of said steam boiler wherein said pressurized steam is otherwise not in demand in said steam circuit within a facility containing said steam boiler; c) causing hot water to flow to an end use from said hot water outlet upon demand from the end use so as to draw water through said steam-to-water heat exchanger from said cold water infeed; d) causing said steam flow regulator to open steam flow upon said trigger signal to allow flow of steam from said boiler through said steam-to-water heat exchanger upon detection by said temperature sensor of a hot water temperature below the threshold temperature; e) causing said steam flow regulator to close off steam flow to said steam-to-water heat exchanger upon detection by said temperature sensor of a hot water temperature at or above said threshold temperature.