A novel combined power generation and argon liquefaction system; investigation and optimization of energy, exergy, and entransy phenomena

The present study proposes a novel cogeneration power plant powered by a double-flash geothermal system. A double-flash geothermal system with a high-and low-pressure turbine was employed to produce power. Moreover, a low-temperature ORC with a turbine was utilized to produce power from the double-flash geothermal waste heat, and the pre-cooled Linde-Hampson cycle was included for Argon liquefaction by consuming a portion of the net power output for initiation. The system is simulated using Engineering Equation Solver software (EES) to specifically analyze the process in each state. The system was investigated concerning the first and second laws of thermodynamics and entry loss. Four conventional working fluids were thermodynamically assessed to identify one with the highest compatibility with the system purposes. The findings demonstrate that the system generates sheer work by 235.5 kW and Argon liquefaction by 0.115 kg/s. The efficiency for the first law of thermodynamics, energetic efficiency, and the entrance loss was calculated; namely, 14.37%, 63.5%, and 1.265 MW.K, respectively. The computation for total exergy destruction in the system was 370.68 kW. The most significant exergy destruction emerges in the evaporator, by 73.78 kW. In addition, the study presents a parametric evaluation of the system to perform minimization and maximization of exergy efficiency and entrance loss based on geofluid temperature, the inlet pressure of flash chamber 1, the inlet pressure of flash chamber 2, the outlet pressure of compressor 1, figure of merit, and superheater temperature difference. Further, the condensers were substituted with thermoelectric generators to condense the turbine output fluid and produce power. The total output power from the thermoelectric generators was calculated as 18.853 kW, singlehandedly elevating the exergy efficiency by 4.23%. Ultimately, single-and multi-objective optimizations (weighted sum) were carried out. eta(I) was 15.01% with w(1) = 1 weight coefficient in Thermal Efficiency Mode, eta(II) was 66.12% with w(2) = 1 weight coefficient in Exergy Efficiency Mode, and G(loss) was 1.136 MW.K with w(3) = 1 weight coefficient in the Low Entry Mode.

Automated summary

This study proposes a cogeneration power plant powered by a double-flash geothermal system, which can produce power and liquefy argon. By analyzing the process in each state and evaluating and optimizing the parameters, the efficiency can be improved and energy loss can be reduced.