Patent ID: 7891415

Claim:
A fuel cell system comprising a heat exchanger having a heat exchange part, wherein the heat exchanger comprises: a heat supply medium channel comprising a plurality of heat supply passages; a heat recovery medium channel surrounding the heat supply medium channel; and one or more fins in a peripheral part of the heat recovery medium channel and in parts of the heat recovery medium channel between two adjacent heat supply passages, wherein the heat exchange part is arranged such that, during operation, a heat supply medium passing through the heat supply medium channel exchanges heat with a heat recovery medium passing through the heat recovery medium channel, wherein the one or more fins form a wave pattern, and a pitch of the wave pattern of the one or more fins in the peripheral part of the heat recovery medium channel is smaller than a pitch of the wave pattern of the one or more fins in the parts of the heat recovery medium channel between two adjacent heat supply passages, wherein cross-sectional space available to accommodate heat recovery medium flow in different sections of the heat recovery medium channel is proportional to an amount of heat to be transferred from the heat supply medium to the heat recovery medium in each of the different sections, wherein each heat supply passage has a vertically elongated cross section and a predetermined width, and the heat supply passages are arranged parallel to one another in a transverse direction with spacing therebetween.