Systems and methods for using an endothermic fuel with a high heat sink capacity for aircraft waste heat rejection

A fuel circulation system for rejecting waste heat produced by one or more operating systems carried on an aircraft, the system comprising:

• a fuel reservoir for storing a reserve of an endothermic fuel that contains an effective amount of branched alkanes so that the endothermic fuel achieves a net endothermic effect when the branched alkanes undergo in endothermic catalytic cracking;
• one or more operating systems that generate waste heat while performing their intended functions during operation of the aircraft;
• a jet engine configured to selectively receive and combust a variable quantity of the endothermic fuel contained in the fuel reservoir;
• a fuel delivery conduit for delivering an endothermic fuel flow originating in the fuel reservoir to the jet engine;
• a fuel return conduit for returning at least some of the endothermic fuel flow not combusted in the jet engine to the fuel reservoir;
• and
• a cracking catalyst cell in fluid communication with either the fuel delivery conduit or the fuel return conduit and exposed within a flow path of the endothermic fuel flow, the cracking catalyst cell comprising an immobilized compilation of a cracking catalyst that includes a superacid operative to induce catalytic cracking of the branched alkanes at a temperature between about 20° C. and about 80° C., and wherein the cracking catalyst cell includes an amount of the superacid to catalytically crack the branched alkanes present in the endothermic fuel and to increase a heat sink capacity of the endothermic fuel flow.