1. Technical Field
The present disclosure relates to a heat exchanger for heat exchange between mediums having different levels of thermal energy, a method of producing the heat exchanger, and a fuel cell system.
2. Description of the Related Art
Heat exchangers such as a plate heat exchanger and a double pipe heat exchanger are traditionally used to exchange heat between two fluids (mediums) having different levels of thermal energy.
The technology of the heat exchanger is applied to a heat exchanger that is disposed in a fuel cell unit, for example. The heat exchanger disposed in the fuel cell unit heats an oxidant gas, which is used for power generation reaction in the cell, with heat of a combustion gas generated by combusting unused gas that is not used in the power generation (see Japanese Unexamined Patent Application Publication No. 2013-211202, for example).
The heat exchanger disclosed in Japanese Unexamined Patent Application Publication No. 2013-211202 includes an oxidant gas channel through which the oxidant gas to be heated flows, a plurality of guide plates that allow the oxidant gas to flow in a serpentine shape, an oxidant gas inlet member through which the oxidant gas enters the heat exchanger, and a plurality of oxidant gas outlet members through which the oxidant gas is supplied to a fuel cell assembly. The heat exchanger further includes an opening, which limits the flow of the oxidant gas, at a downstream end of the oxidant gas channel, which is positioned downstream of the guides. The distances between the opening and the oxidant gas outlet members are equal. With this configuration, the heat exchanger having the oxidant gas channel extending in the serpentine shape allows the oxidant gas to be equally supplied to each fuel cell.