Complete power cycle exhaust heat regeneration and the second law of thermodynamics

Abstract

A closed condensing power cycle using tetrafluoromethane or R14 and a solid solute as its working fluid is described. The inclusion of a solid solute that yields a positive excess enthalpy of solution with the R14 creates a potential for complete exhaust heat regeneration. The solution reaction provides a temporary thermal reservoir for the cycle's low temperature exhaust heat until that energy is regenerated as heat by retrograde solubility during the cycle's high temperature and low density expansion phase. A slow solute dissolution rate in the solvent's low density state near the cycle's high temperature enables the cycle to utilize all of the regenerated exhaust heat either as work output or by exhausting surplus heat at a second temperature level. The cycle's thermodynamic path establishes solvent property reference points that can be used to determine the maximum positive excess enthalpies of solution required for a solvent to accomplish total exhaust heat regeneration when used as the cycle's working fluid.