Breaking the Carnot Limit with a Gravity-Driven Work Cycle

Both classical thermodynamics and the Carnot cycle rely on temperature differences as their core working principle, depend on artificial compression to maintain pressure differentials, and are constrained by low-temperature heat source waste heat discharge, with their efficiency limits defined by the Carnot theorem. However, gases in gravitational fields exhibit fundamental differences, possessing natural pressure gradients and energy enrichment. This study systematically investigates the unique thermodynamic behavior of gases in gravitational environments. First, we demonstrate a strict coupling relationship between internal energy and gravitational potential energy in static atmospheres, proving they are interconvertible rather than independent energy sources. Second, we propose a static lapse rate distinct from adiabatic lapse rate, revealing that gravitational fields can form stable temperature gradients. Building upon these pressure and temperature gradients, we construct a gas working cycle requiring neither artificial compression nor waste heat discharge. Under isothermal and polytropic atmospheric models, both work-driven and heating-driven configurations achieve energy utilization efficiencies far exceeding Carnot theorem limits. Isothermal models directly confirm that high cycle efficiency can depend solely on gravitational pressure differentials, while non-isothermal models show that increased temperature gradients enhance efficiency but elevated heating temperatures reduce it. This cycle fundamentally diverges from Carnot cycle's temperature-difference-based working mechanism, achieving thermal efficiency surpassing Carnot theorem limits under identical temperature differentials. Utilizing macromolecular gases enables engineering implementation at heights as low as 100–300 meters, providing novel pathways for environmental thermal energy utilization and energy conservation.