The recovered heat from the flue gases serves multiple purposes, depending on its application within the system. When channeled back into the boiler's feed water, it functions as a "feed water economizer," significantly reducing the energy required to heat the water to the necessary temperature. In scenarios where the heat is diverted for facility needs such as operational water, bathing, processing, or washing, it assumes the role of a "domestic water economizer," effectively utilizing waste heat for practical applications.