A method for creating work by adsorption end desorption of a working fluid on an fiber sorption system which has a plurality of tubular hollow fibers within a vessel which is connected to a work device. Each fiber is in the form of a tubular, elongated body composed of a sorbent material capable of adsorbing a working fluid such as carbon dioxide. The fibers have an inner surface adjacent the hollow interior and an outer surface, one of which has a coating layer which is impermeable to both a working fluid and thermal fluid. The system is operated by passing a thermal cooling fluid in contact with the fibers to cool the fibers and passing the working fluid over the fibers in contact with the surface of the cooled fibers which does not have the coating layer so that the working fluid is adsorbed on the fibers, the adsorbed working fluid is then desorbed from the fibers by passing a thermal heating fluid in contact with the fibers to heat the fibers; the pressurized, desorbed working fluid is then passed to a work device connected to the vessel.