Prospects of Increase of Small Micro Turbine—CHP Systems Efficiency by Perfection of the Thermodynamically Cycles

The paper summarizes the results of research into the concept for small residential CHP systems based on Low-Power Micro Turbine Generators (MTG) to meet the requirements related to main key indicators: Initial Costs (IC) $400–500/kW; lifetime of at least 10 years, low Operating and Maintenance Costs (O&MC) and so on. The paper illustrates the possibility to meet these requirements by designing MTG based on unification with mass production low cost automobile turbochargers and other parts of ICEs. The analysis of the reasons for the inadequate thermal efficiency of such MTGs has been conducted. The limited possibilities for their improvement have been shown by moving from simple conventional Brayton cycle (S-cycle) to more complex cycles. At the same time, the potential and benefits of the Inverted Brayton cycle (IB-cycle) are established, especially for Low-Power MTG. Presented for discussion are the fundamentals of the concept for CHP systems based on low-power MTG. They must be adapted for mass production, must use different fuels (gas, biogas, biofuel, biomass, waste, etc.), must work together with rapidly developing alternative energy sources (Solar PV, wind turbines etc.) and have the required environmental safety.