LATENT HEAT RECOVERY DEVICE, WATER HEATER, OPERATIONAL METHOD OF LATENT HEAT RECOVERY DEVICE

摘要

To provide a latent heat recovery device capable of reducing the acidity of drain discharged from the same, a water heater having such a latent heat recovery device, operational method of such a latent heat recovery device.SOLUTION: A latent heat recovery device 10 is provided that comprises: a heat exchanger 12 heating an object W by latent heat generated when steam included in combustion gas C generated by combustion of fuel F with combustion means 30, is condensed; and a catalyst part 11 in contact with the combustion gas C before introduced to the heat exchanger 12, wherein the catalyst part 11 has an adsorbent reversibly adsorbing nitrogen oxide and a reduction catalyst reducing the nitrogen oxide. A water heater 1 having such a latent heat recovery device 10 is also provided. The operation of the latent heat recovery device 10 is provided with a reduction period in which the catalyst part 11 is maintained under the first condition that the adsorbent is apt to adsorb the nitrogen oxide during the period of time that the object W is heated, and the catalyst part 11 is maintained under the second condition that the reduction catalyst is apt to reduce the nitrogen oxide during the period of time that the object W is not heated.SELECTED DRAWING: Figure 1