METHOD AND DEVICE FOR PREHEATING WATER AND/OR HOT WATER SUPPLY AND HEAT GAS GENERATOR Russian patent published in 1994 - IPC

FIELD: heating systems. SUBSTANCE: circulating liquid flow and heated gas flow are formed in housing Heat transfer is formed between these flows with condensation of water steam in gas flow. Condensate is discharged. External flow of water for hot water supply is fed and heat transfer from flow of circulating liquid to external flow of water is formed. Then flow of circulating liquid is divided into two flows at control of their flow rates. One of these flows is cooled with external flow of water to temperature below dew point dew point of water steam of heated gas flow. Then heat is transferred to divided flow at countercurrent flow inside terminal part of heated gas flow; condensate is discharged between terminal and center parts of heated gas flow downstream. Then divided flows are joined. Heat transfer is effected in center part of heated gas flow downstream to the combined flow. In the initial part of heated gas flow downstream, heat is transferred to the combined flow in parallel current. Heat transfer from circulating liquid flow to external flow of water is first effected from one of divided flows and then from joined flow after it has passed initial part of heated gas flow downstream. EFFECT: enhanced efficiency. 25 cl, 35 dwg