| 摘要 |
PROBLEM TO BE SOLVED: To improve heat efficiency by reducing an exhaust gas temperature in a vacuum-type water heater having two hot water circuits of hot water for hot water supply and hot water for air-heating.SOLUTION: A vacuum-type water heater includes a first vacuum-type water heater 5 including a burner 2, a first heat exchanger 3 for hot water supply, and a first heat exchanger 4 for air-heating, and a second vacuum-type water heater 8 including a second heat exchanger 6 for hot water supply and a second heat exchanger 7 for air-heating and constituted to heat a heat medium by an exhaust gas of the first vacuum-type water heater 5. The first heat exchanger 3 for hot water supply is connected to the second heat exchanger 6 for hot water supply in series to be supplied water from the second heat exchanger 6 for hot water supply, and the first heat exchanger 4 for air-heating is connected to the second heat exchanger 7 for air-heating in series to be supplied water from the second heat exchanger 7 for air-heating. |
