The invention is a process and device for exchanging heat energy between streams in a microchannel heat exchanger which can be integrated with a microchannel reactor to form an integrated microchannel processing unit. The invention enables the combining of a plurality of integrated microchannel devices to provide the benefits of large-scale operation. In particular, the process comprises: (a) carrying out an endothermic reaction in a first microchannel; (b) flowing a fuel through a second microchannel; (c) flowing an oxidizer through a third microchannel; (d) combining the oxidizer and the fuel, wherein the fuel and the oxidizer are converted to at least one exhaust product, whereby thermal energy is produced; and (e) transferring at least a portion of the thermal energy to the first microchannel.
