| 摘要 |
PROBLEM TO BE SOLVED: To reliably prevent freezing of detention water in each water tube of a heat-exchanger for recovery of a latent heat by utilizing a heater having low capacity. SOLUTION: A heat-exchanger 4 for recovery of a latent heat is constituted that a plurality of linear water tubes 15 are communicated and connected together through a U-shaped water tube 17 to form a water flow passage. The linear water tubes 15 forms a multiple pipe structure formed that an outer tube 21 is fitted in an inner tube 20. The outer tube 21 is formed of stainless having excellent corrosion resistance and the inner tube 20 is formed of copper having higher thermal conductivity than that of the outer pipe 21. The U-shape water tube 17 is communicated and connected to the inner tube 20 and a heater 22 is arranged in the U-shape water tube 17. The heater 22 heats the U-shaped water tube 17, and when heat is transmitted from the heated U-shaped water tube 17 to one end part of the inner tube 20, heat is immediately transmitted to the other end side of the inner tube 20. This constitution uses a heater having low capacity for prevention of freezing. |
