Thermodynamic and economic analysis of a micro-combined polygeneration system coupled with solar energy and fuels for distributed applications

A novel micro-combined polygeneration system based on solar energy and fuels is designed with aim to simultaneously satisfy energy demands of electricity, heating and cooling in distributed areas. Integration solar radiation with conventional natural gas-fired power systems is conceived to eliminate existing disadvantages of low efficiency and high cost for fuel-only and solar-only plants. Thermodynamic and economic analyses are evaluated to explore performance of proposed systems with three working fluids. Energetic and exergic efficiencies are individually 0.839 and 0.4536, 0.8721 and 0.5852, and 0.8656 and 0.5825 for N₂-, He- and Ar-based micro-combined systems under specified power capacity of 100 kW. Solar collector field, compressor, turbine and combustion chamber exhibit four largest exergy destruction, followed orderly by heat exchanger, generator, condenser, evaporator, throttling valve and pump. Preliminary economic analysis indicates that levelized electricity costs of N₂-, He- and Ar-based micro-combined systems are 0.112, 0.103 and 0.101 $ kWh⁻¹ with corresponding payback periods of 4.563, 5.090 and 5.138 years. Parametric analysis reveals that five operating parameters (compression ratio, turbine inlet temperature, solar collector field outlet temperature, generator outlet temperature and split ratio) exert noticeable influence on thermal efficiency of micro-combined systems. In conclusion, proposed micro-combined polygeneration system achieves efficient conversation of thermal energy into electricity, heating and cooling at a rational energy utilization for distributed areas.