VACUUM TYPE WATER HEATER

To increase thermal efficiency, reduce annual energy consumption and running cost and reduce CO2 while controlling a device from being complicated and increased in size.SOLUTION: A vacuum type water heater includes: a sealed can body 2 of which interior is held to be atmospheric pressure or less; a heat medium liquid tank 4 formed in a lower part in the sealed can body 2 to store heat medium liquid 3 therein; a decompression steam chamber 5 formed in an upper part in the sealed can body 2; a hot water heat exchanger 6 disposed in the decompression steam chamber 5 to condense and liquefy steam generated inside the decompression steam chamber 5 by exchanging heat of the steam with water; and heating means 7 disposed in the heat medium liquid 3 in the heat medium liquid tank 4 to heat and evaporate the heat medium liquid 3. The heating means 7 includes: a main heater 8; and an auxiliary heating device 9 of which output power is larger than the main heater 8. The auxiliary heating device 9 is disposed on a lower side in a vertical direction of the main heater 8.SELECTED DRAWING: Figure 1 【課題】 装置の複雑化と大型化を抑制しながら、熱効率が高く、年間エネルギー消費量とランニングコストの低減及びＣＯ２の削減等を図れるようにする。【解決手段】 内部が大気圧以下に保持された密閉状の缶体２と、缶体２内の下部に形成されて熱媒液３を貯留する熱媒液槽４と、缶体２内の上部に形成された減圧蒸気室５と、減圧蒸気室５に配置されて減圧蒸気室５内に発生した蒸気を水との熱交換により凝縮し液化させる温水熱交換器６と、熱媒液槽４内の熱媒液３中に配置されて熱媒液３を加熱蒸発させる加熱手段７とを備える。加熱手段７は、主加熱器８と、主加熱器８よりも出力が大きい補助用加熱装置９とを備える。補助用加熱装置９は主加熱器８の鉛直方向下方に配置されている。【選択図】 図１