A method of utilizing waste heat to create a pressurized working fluid is disclosed. The method includes providing a vessel containing a sorbent system, introducing a feed of waste heat to a heat exchanger external to the vessel to heat a feed of working fluid, introducing the heated working fluid from the heat exchanger to the vessel to obtain pressurized working fluid, and directing the pressurized working fluid from the vessel to a work component. The method is particularly suited to make use of waste heat an industrial process, (e.g., a chemical processing or petrochemical refining operation) in which low grade heat source(s) are used to drive the sorption system.