| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a highly efficient water heater requiring no neutralizing treatment for drain water. <P>SOLUTION: In a main heat exchanger 18, sensible heat in combustion gas is recovered without generating drain, and in a subsidiary heat exchanger 19, sensible heat and latent heat in the combustion gas are recovered while reducing the temperature of the combustion gas to that of generating the drain. The drain generated in the subsidiary heat exchanger 19 has contact with externally heated air on a drain evaporator 100. In such construction that the air heated outside a combustion chamber is used for surely evaporating the drain, no need exist for installing a neutralizing device to neutralize the generated drain. Heat efficiency is improved compared with the case of using the combustion gas for evaporating the drain. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
