| 摘要 |
PROBLEM TO BE SOLVED: To provide a highly efficient water heater, in which a neutralization treatment of drain is not required. SOLUTION: In a main heat-exchanger 18 the greater part of the sensible heat of the flue gas is recovered without producing drain, and the running water is heated. In a sub heat-exchanger 19, the temperature of the flue gas is dropped to a drain generating temperature, the sensible heat and latent heat are recovered, generated drain is evaporated in the downstream of the flowing water, and only the latent heat is released to the flue gas. Thus, only the sensible heat is recovered as far as possible in the heat exchangers 18 and 19 to heat the supply water efficiently by the conducted heat. The drain is not discharged to the outside of the water heater 10, accordingly, a device for drain neutralization is unnecessary. |
