摘要 |
In a method and evaporator device for evaporating a low temperature liquid medium, such as hydrogen for example, the hydrogen is first evaporated and at least partially superheated in a forward-flowing first channel, and is then directed to flow back in the opposite direction in a second return-flowing channel. The second channel is especially interposed between the first channel and a passage through which flows a heat-providing medium such as a hot exhaust gas. Thus, the superheated hydrogen flowing in the second channel serves as an intermediate layer for heat transfer from the heat-providing medium through the hydrogen in the second channel to the low temperature, initially liquid hydrogen in the first channel. The heat exchange surfaces in contact with the heat-providing medium are not directly adjacent the extremely cold surfaces in contact with the in-flowing low temperature liquid hydrogen, and the superheated hydrogen acts as a buffer between the hot side and the cold side of the evaporator. As a result, the evaporator has a very low structural weight, and condensation and icing problems can be avoided even when using a hot medium and a cold medium having extremely different temperatures.
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