Patent ID: 6612267
Filing Date: 2003-09-02
Classification: F24D,F24H

Abstract:
A hot water heater comprising:an instantaneous domestic water heat exchanger having a plurality of inner flow passages for domestic water flow therethrough and means defining a domestic hot water inlet and outlet communicating therewith, said heat exchanger also having at least one boiler water passage located adjacent to the inner domestic water flow passages and means defining a boiler water inlet and outlet communicating therewith; a temperature sensor attached to the heat exchanger to sense the temperature of the domestic hot water therein; a low mass boiler-type heat generator having an internal reservoir defining a boiler water inlet and outlet, a source of heat energy for heating water in the reservoir, and thermostatic means operably connected to the source of heat energy for maintaining the boiler water inside the reservoir between predetermined minimum and maximum temperatures; a boiler water flow circuit connecting the heat exchanger and the heat generator reservoir in series, said circuit having a supply line for the flow of boiler water from the heat generator reservoir outlet to the heat exchanger boiler water inlet, and a return line for the flow of boiler water from the heat exchanger boiler water outlet back to the heat generator reservoir inlet; pump means located in the flow circuit and coupled to the domestic water temperature sensor for causing boiler water flow through the heat exchanger upon the domestic water temperature therein dropping below a predetermined temperature; and the heat generator reservoir being of a size large enough to enable the heat exchanger to supply short term domestic water demand and small enough to avoid excessive downtime energy losses.