Abstract
The thermodynamic mechanism of self-heat recuperative and self-heat recovery heat circulation system for a continuous isobaric heating and cooling gas cycle process without chemical reaction has been studied in terms of the exergy analysis by using energy conversion and temperature-entropy diagrams. The modularization of the thermal gas cycle process which is decomposed into four thermodynamic elementary process modules, isobaric heating and cooling process modules (HR and HT) and adiabatic compression and expansion process modules (WR and WT), and a heat exchange process module (HX) indicates that in four thermodynamic elementary process modules (HR, HT, WR, and WT) both exergy and anergy are conserved except for HX in which the exergy is transformed into the anergy because of the exergy destruction due to the heat transfer. In the self-heat recuperative heat circulation system for the heating and cooling gas cycle process, providing the minimum work required for the heat circulation to compensate for the exergy destruction in HX the process heat is recuperated with increasing temperature of process fluid from T to T+ΔT and then recirculated through HX. The minimum work required for heat circulation, or work input, is converted to heat output, or the thermal energy of which anergy and exergy are the exergy destruction due to heat transfer in HX and the exergy to discard the anergy transformed by the exergy destruction, respectively. For the conventional self-heat recovery heat circulation system by providing heat instead of work the additional exergy to discard the anergy of heat input into the environment is needed with the minimum work required for heat circulation to compensate for the exergy destruction due to the heat transfer in HX, increasing the energy requirement for heat circulation by self-heat recovery.
