Thermo-Chemical Engines: Unexploited High-Potential Energy Converters

Thermal engines, and in particular closed power cycles, are currently a focus of attention of many researches mainly because they represent the only way to exploit renewable thermal energies. To contribute to boosting the exploitation of available thermal sources, this work investigates the higher potential offered by a complementary technology, based on the use of reactive working fluids instead of inert ones: the here-called “thermo-chemical” engine. Such a power cycle enables the simultaneous conversion of thermal and chemical energies into power. With a theoretical approach, we analyse engine performances considering different stoichiometries and thermodynamic characteristics of reactive fluids and different operating conditions. It is shown that the use of specific equilibrated reactions occurring in the gaseous phase might lead to extremely powerful and highly efficient energy conversion systems, in the whole current domain of application of power cycles. Moreover, we demonstrate that, differently from classical thermal machines, a thermo-chemical engine allows for the efficient and powerful exploitation of low temperature heat sources and high temperature cold sinks which in general characterize renewable thermal energies.