NOVELTY - A heat-transport system (400) has reactor (421) which has catalyst (I) which generates a return fluid from feed fluid and heat exchanger (I) which outputs the heat, reactor (461) which has catalyst (II) which generates feed fluid from the return fluid and heat exchanger (II) which inputs the heat, feed fluid path (410) which is formed between and connecting reactor (421) and reactor (461) and in which the feed fluid generated by reactor (461) flows, return fluid path (450) in which return fluid generated by reactor (421) flows, and expander arranged at path (450).    USE - Heat transport system used for removing and transporting electric power generation exhaust heat from solar thermal power generation to system for freshwater manufacture.    ADVANTAGE - The heat transport system is simple, economical and has improved reliability, and enables effective removal and usage of exhaust heat of solar thermal power generation in freshwater manufacture.    DETAILED DESCRIPTION - A heat-transport system has reactor (421) which has catalyst (I) which generates a return fluid from feed fluid by exothermic reaction and heat exchanger (I) which outputs the heat generated by exothermic reaction, reactor (461) which has catalyst (II) which generates an feed fluid from the return fluid by endothermic reaction and heat exchanger (II) which inputs the heat used for endothermic reaction from outside, feed fluid path (410) which is formed between reactor (421) and reactor (461) which are connected and in which the feed fluid generated by reactor (461) flows, return fluid path (450) which is formed such that connecting reactor (421) and reactor (461), and in which return fluid generated by reactor (421) flows, and expander arranged at path (450).    DESCRIPTION OF DRAWING(S) - The drawing shows the heat-transport type solar thermal power generation system.    Expander (200)    Heat-transport system (400)    Feed fluid path (410)    Reactors (421,461)    Gas-liquid separator (425)    Feed fluid tank (430)    Return fluid path (450)