Process and system for boosting the temperature of sensible waste heat

Abstract

Sensible waste heat from industrial or other sources is boosted to useful temperature levels by combining at least one Rankine vapor generation cycle with at least one solution heat pump cycle. Waste heat is first utilized to boil off refrigerant in the Rankine cycle evaporator to provide a source of relatively high pressure vapor to an absorber in the solution heat pump. In the absorber, the vapor is contacted with a working solution of absorbent and refrigerant. As the refrigerant vapor is absorbed into solution, its latent heats of condensation and solution are given off at a temperature higher than the temperature of to a process (boosted output) stream the waste heat source. The working solution is then throttled to a relatively low pressure desorber where a portion of the refrigerant is desorbed as vapor from the solution by the further use of waste heat. The desorbed refrigerant vapor is then condensed and pumped to the evaporator for reuse. Working solution is recycled from the desorber to the absorber for reuse. Utilization of the sensible waste heat, first source is maximized by extracting successive portions of heat for use in the Rankine cycle evaporator section and then in a heat pump cycle desorber section. Multiple cycle systems are disclosed which boost the temperature of a portion of the waste heat to even higher levels than possible from the single cycle system.