Energy recovery system for boiler and domestic water

摘要

A preheater unit which includes a chamber for boiler water and a domestic water heating coil is arranged in heat exchange relationship with the exhaust duct of a boiler of a heating system for extracting heat from the flue gases. Boiler water may be shut off to the heat radiating system in the summer although boiler water is fed to the preheater unit both in summer and in winter. The domestic water heating coil within the preheater unit is connected in series flow relationship with the domestic water heating coil interiorly of the boiler. A summer/winter switch is added to the conventional boiler circuitry to enable control of the water circulator by the thermostat in the winter, while the water circulator is operated by the upper limit aquastat during summer operation whenever the burner of the boiler is energized.